GWR Helmholtz rattle question [Archive] (2024)

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warthogdrifter

11th May 2017, 03:42

I recently installed a full gwr set up with a HH mid. I have this terrible rattle when the car is cold for about 2 miles. After that what I believe to be a bad cat Heats up enough to stop whatever is moving around. I have thoroughly checked everything and found my cat to rattle when I tap it. I called GWR and they told me it's something to do with the HH and that they all sound like this. Is this true? Do all HH mid pipes sound like they are broken until heating up? It's really upsetting that my brand new $1500 exhaust sounds like complete garbage until it warms up. I'm literally embarrassed to give it any throttle until the rattle goes away... Any input from HH owners would greatly help...

Pstone

11th May 2017, 08:50

I have the same issue as well. After 10-15 min the rattles go away. About ready to dump the HH midpipe and just get a resonated one.

bstabile

11th May 2017, 09:38

No issues at all with the HH mid for me.

What did cause a vibration was the mid-pipe bracket joining fore and aft. When first installed the bolt was horizontal at the bottom. It looked like there was enough clearance with the stock brace below it. But I had to reposition the bracket so the bolt was vertical facing the PPF, with the nut facing down so it can be wrenched. The head of the bolt is gripped by the bracket so you'll never need to get a wrench on that. Once I made that change, there is plenty of clearance. There is also plenty of clearance with respect to the frame (PPF).

Problem solved (for me anyway).

warthogdrifter

11th May 2017, 11:23

No issues at all with the HH mid for me.

Problem solved (for me anyway).
I did the same thing initially with that flange and immediately fixed it. This issue is internal and it drives me insane. It sounds so cheap.

warthogdrifter

11th May 2017, 11:25

Bracket***

warthogdrifter

11th May 2017, 11:26

I have the same issue as well. After 10-15 min the rattles go away. About ready to dump the HH midpipe and just get a resonated one.
If the solution is me having to buy another 400+ mid pipe that is completely unacceptable.

JTod

11th May 2017, 11:44

Mine sounds different (worse) until warm as well. I have the GWR catted header, HH, and SuperQ. When I bang on the HH with my hand I hear some kind of rattle that sounds internal. If they said "they all do that" what did they say the cause is? I agree that it is annoying.

warmmilk

11th May 2017, 11:50

My cat rattles when you hit it, but sound doesn't really change much from cold to warmed up

bstabile

11th May 2017, 11:58

Is this a symptom that shows up over time? Or was it like that from day one?

I've got almost 15k on mine with no hint of rattle.

Super Josh

11th May 2017, 12:59

No issues at all with the HH mid for me.

Problem solved (for me anyway).

I'm sorry but I'm having difficulty understanding your description of the part (maybe it's a UK - US thing? :) ). Are you referring to the clamp around the slip joint between the two parts of the Helmholtz mid-pipe? And locating the clamping bolt so that it is adjacent to the PPF so that it won't knock against the under body bracing?

Cheers,

Josh

05RC51

11th May 2017, 13:11

Check out my post... 21136

https://forum.miata.net/vb/showthread.php?p=8468225#post8468225

05RC51

11th May 2017, 13:13

I also had an issue with one of the hangars just ever so lightly touching the pipe and buzzing.

cola571

11th May 2017, 13:53

This is the rattle I had. The back half of my midpipe is currently being warrantied. https://youtu.be/jfvriq5H6B0?t=27s

warthogdrifter

11th May 2017, 14:29

Is this a symptom that shows up over time? Or was it like that from day one?

I've got almost 15k on mine with no hint of rattle.

It's been like this from day one. Initially I was not concerned thinking it just needed to be adjusted. It's still fairly new as I installed almost exactly 3 months ago. In a previous post Brian instructed me to call and get it swapped out. That's when I got my explanation that this noise is normal with HH mids... I really should have and still might pursue it more. I forgot the exact reason as to what the cause is, but if there are people with perfect HH Mids with no rattle I really feel burned.
Is this a symptom that shows up over time? Or was it like that from day one?

I've got almost 15k on mine with no hint of rattle.

warthogdrifter

11th May 2017, 14:31

This is the rattle I had. The back half of my midpipe is currently being warrantied. https://youtu.be/jfvriq5H6B0?t=27s
Mine is not that horrible I would have noticed that haha. It's going on a lift again this weekend and I'm going to take another look.

warthogdrifter

11th May 2017, 14:41

Check out my post... 21136

https://forum.miata.net/vb/showthread.php?p=8468225#post8468225
Did the clamp fix the issue or was it exclusively the muffler hangar causing it?

Pstone

11th May 2017, 16:55

I've adjusted my HH mid pipe multiple times. Have tried removing all bracing, shortened & lengthened the midpipe, still can't get vibration to go away until after the exhaust warms up. It is embarrassing having the car buzzing like a Honda when you try to accelerate beyond 1/10th throttle for the first 10 minutes when cold.

It is pretty disappointing after having spent close to $1700 for the full exhaust with ceramic coating shipped to my door. Within the first few months, the welds of the HH chamber started to fail. I did a full test of the exhaust, and every weld had a leak. This included where the header tubes merge into one, the cat, the HH chamber, and even the Super Q. Was going to cost well over $100 shipping for warranty repairs, so I had a local welder fix and add bracing to the HH chamber. Design, figment, and company that completes the welding may need to be updated. I'm happy that GWR puts in the time and energy to come out with these products, but the end result is lacking for how much it costs.

05RC51

11th May 2017, 17:13

Did the clamp fix the issue or was it exclusively the muffler hangar causing it?

New clamp got rid of it.

Installed the clamp and torqued to whatever the spec on the box was.
Leave the sticky black goo on the new clamp alone, its supposed to be there....
You dont need to separate the pipes to remove the original or install the new clamp.

Amazon
Dynomax 33226 $13+/-.

warthogdrifter

11th May 2017, 17:18

New clamp got rid of it.

Amazon
Dynomax 33226 $13+/-.
Purchased will install Saturday. Thanks I hope it does the trick.

rherold9

11th May 2017, 18:42

New clamp got rid of it.

Amazon
Dynomax 33226 $13+/-.

Thank you. Haven't installed mine yet. Going to purchase one of these so I don't have to deal with this.

It's honestly not a good excuse for GWR to say but all of them do it. It should be fixed for how much their exhausts pieces cost. Whether it's better hardware mounting pieces or the welds not holding up. I don't care how much time and effort one puts into this if they say it's okay "because all of them do it" it's not acceptable, imo.

warthogdrifter

11th May 2017, 21:01

Thank you. Haven't installed mine yet. Going to purchase one of these so I don't have to deal with this.

OKMiata

11th May 2017, 22:09

If it truly is the cat rattling then do what I did an have the cat cut out and weld in a straight pipe. Problem solved and sounds great!!!!

bstabile

12th May 2017, 06:04

Thank you. Haven't installed mine yet. Going to purchase one of these so I don't have to deal with this.

As I have said, not all of them do that. I don't know why you were told it is normal. I have zero vibration once I adjusted the clamp. And that was just an installation issue, not a problem with the product. I've had no weld issues either. Solid as can be so far, after eight or nine months and 15k miles.

bstabile

12th May 2017, 06:35

Cheers,

Josh

Correct. Here is a picture of it (just forward of the HH chamber):

https://forum.miata.net/vb/attachment.php?attachmentid=260884&d=1487394954

This is before I adjusted it. Notice that if I just turned it in place the nut would be at the top, no way to wrench it. I had to remove the bracket and flip it 180 so when the bolt is vertical (on the PPF side) the nut is facing down. If you just turn it without flipping the nut will be facing down but the bracket will interfere with the heat shielding (opposite side from the PPF).

Hope that helps.

EDIT: As I mentioned earlier, you do not need to get a wrench on the head of the bolt itself. It is "embedded" so it can be up top. Only the Nut needs to be accessible.

Super Josh

12th May 2017, 07:52

Correct. Here is a picture of it (just forward of the HH chamber):

https://forum.miata.net/vb/attachment.php?attachmentid=260884&d=1487394954

Hope that helps.

EDIT: As I mentioned earlier, you do not need to get a wrench on the head of the bolt itself. It is "embedded" so it can be up top. Only the Nut needs to be accessible.

Perfect :thumbs::thumbs:

Cheers,

Josh

warthogdrifter

14th May 2017, 16:39

New clamp got rid of it.

Amazon
Dynomax 33226 $13+/-.
Just installed the new clamp it's really nice, but the problem persists. I'm 1000% sure it's the cat. You can hear stuff rattling around when you lightly bump it. Everything else is rock solid and there are no clearance issues.

OKMiata

14th May 2017, 17:57

Just installed the new clamp it's really nice, but the problem persists. I'm 1000% sure it's the cat. You can hear stuff rattling around when you lightly bump it. Everything else is rock solid and there are no clearance issues.

is there a reason you can't cut out the cat and weld in a straight piece? If you don't have emissions checks in Florida, then problems solved. It will be a tad louder but definitely livable. this is what I did with my HH so as to not eventually ruin the cat due to turbo application.

warthogdrifter

14th May 2017, 17:59

I'd rather not go catless. That will throw a code and probably not smell to great haha.

bstabile

14th May 2017, 18:03

It almost sounds to me like there might be some bits of welding slag or other waste material in there rattling around. I don't know how that can possibly be considered "normal" if the sound is not typical. Obviously many of us hear nothing at all rattling around. I think you would be hearing many more complaints if that was a normal condition for the product. I certainly wouldn't be happy about it and I would expect some kind of remediation!

warthogdrifter

14th May 2017, 18:04

I'll call them again tomorrow

mx5mia

15th May 2017, 08:34

I have had my R/S, HH mid pipe on for a couple thousand miles and no vibration yet since new. I installed it onto my stock header.

I did notice the bottom edge of the pipe almost touched the front cross brace. I had to bend the brace bowed down a little to give it some clearance.

Also, the wide flat clamp does not crush the pipe like the old U-shaped pipe clamps that were made from round rods. Put the clamp at the edge of the (outer) pipe joint so it can squeeze the split ends of the outer pipe tight against the inner section.

As mentioned above, I also put the bolt of the clamp in a verticle position with the nut at the bottom. I found the clamp metal stretches a little for a while, so check the torque on it maybe a couple hundred miles after the initial instal.

bstabile

15th May 2017, 09:06

I did notice the bottom edge of the pipe almost touched the front cross brace. I had to bend the brace bowed down a little to give it some clearance.

I put washers on one side of that front brace recently because on routine inspection I thought that clearance was a little tight. I don't know if that compromises the effectiveness of the brace, but I haven't noticed any detrimental effect.

Also, good point about checking the torque (for any new installation). ;)

E39S62

16th May 2017, 00:15

I had to add spacers to the front brace to clear the mid-pipe. The 2.5 on drop brackets sits lower and it made hellacious noise when it banged on the brace!

I haven't noticed any rattling from the cat on my HH and I checked multiple times. I do get some interesting metallic whistling noise on cold start that I can't explain. I've checked all the flanges multiple times for leaks.

JTod

18th May 2017, 14:54

My rattle has nothing to do with braces or clamps. I hear it when I bang on the HH with my hand.

Disappointed that Goodwin doesn't feel the need to chime in here and explain what the issue is - if they are fixing them under warranty they must know.

OKMiata

23rd May 2017, 08:54

So OP, any resolve?

I know you are not keen on removing the cat but doing so will eliminate the possibility of future cat failure and or the possibility it being loose within the pipe. To eliminate the "code" just install a spark plug extender on the second O2 sensor and no code will appear.

Good luck.

dunhamjr

23rd May 2017, 17:52

i am curious too. in the process of buying an NC which has the mazdaspeed rear section, and the boom is killer... the HH pipe seemed like a great option, but not if a rattle/buzz will annoy me instead.

warthogdrifter

23rd May 2017, 18:17

I'm still trying to convince gwr that something is wrong. I made a crappy video and I guess I gave them too much information. Now I have to make a better one to try and prove my case.

orbitaljunkie

25th May 2017, 14:54

Glad this thread exists... I thought I was going crazy. I have the full GWR setup and yeah, so much ****ing rattle when cold that I can't go above 3k RPM. Just ordered the clamp so I hope that helps it, but I'm pretty pissed that this product appears to have this issue considering the price.

txm

25th May 2017, 18:45

Same here. Mid pipe hanger doesnt clear. Had to add spacer. Doesn't clear the ILM braces i got thru gwr. Then the cold rattle started after 5k miles. No help when i sent email asking about rattle.

Had local muffler shop build an exhaust including the 4x17 helmholtz can. Perfect fit, can use braces again, sounds great with no drone. It's not stainless but oh well.

GWR helmholtz midpipe is sitting in the corner of garage. Very disappointed in that product. Their regular midpipe fit great, should have kept it.

TSIGOS

25th May 2017, 21:55

Yeah, I could never get the rattle and buzziness to go away. I took it to 2 different shops who each inspected, disassembled and reinstalled to no avail. One did discover a cracked weld in my SuperQ muffler but that did not fully resolve the issue.

rherold9

26th May 2017, 08:11

It's pretty crazy how we haven't gotten a response from them on this thread with how many people on just one forum alone have the same issue. I can't imagine how many customers actually have the issue and just deal with it. This plain and simply shouldn't be happening and we deserve some sort of an answer, imo. I would have never bought the product if I would've known it would rattle. I wouldn't expect it to have a problem for the price, reputation the company has, and the way they describe it. If mine has the issue I will definitely not sit here and accept it.

Brian Goodwin

26th May 2017, 08:58

I was up 4am today in preparation for a 200 mile journey to the factory to meet with them for hands on look at the way these are made and packaged, QC measures, welding procedures, design questions, etc.

The real head scratch questions come from the fact that we continue to install these here daily and our installs fit consistently with no contacts with any of the braces we sell or stock braces and no weld issues over time. And we see these local installs back daily for other stuff like oil changes and additional mods which gives us lots of opportunity to inspect the installs at regular intervals and our installs are turning out solid month after month, year after year. When we cannot seem to make an install fail here, it makes it really tough to chase down reported issues.

At the same time, I know some customers here had problems and that leaves us baffled as to how our installs here are consistently good and lasting without issue. The original production unit of this midpipe is still on the 2012 PRHT that was my wife's daily driver car for years without issue, then that car sold to a local friend of mine who had it back for all regular service for years without issue, who then sold same 2012 to another customer who has driven it all over the country and seriously racked up the miles and then recently had the car back here after running over a garden rake which tore up the radiator and more under the car(link HERE). (http://www.mazdatalkforum.com/viewtopic.php?f=10&t=2441&start=495) That gave us lots of time under the car looking at that original install yet again, and the exhaust goodies are still perfect. Same story daily with dozens of other installs of the same. So how is it that only customer installs are having issue, is it something that leaves potential contact which then causes vibration and then causes broken welds? Is it a climate thing, our moderate climate here means far less temp swing and thermal contraction/expansion issues are not giving us the range here needed for us to see the same issues? Maybe... It it just too big of an item for the center tunnel, or can we adjust the product to remove more variation in customer installs? Understand that since our installs here do NOT contact the braces or anything else and the welds are not busting on our installs, over 100 installed here to date, that makes it's tough to chase down when we cannot seem to replicate the failure here despite 100+ more installs than any of you will ever see in person. And I cannot imagine how any customer would put more abuse to the system when I have same item on our 300 hp 2007 Supercharged racer with super stiff suspension, 18x10.5 wheels (massively unusual heat load in the tunnel since the supercharger putting down over 300hp at the wheels is effectively a blow torch for exhaust system). Yet that install still issue free too.

I setup a meeting at the factory so I can walk through with them all issues raised by customer installs and look at where we might improve the product to make customer installs smoother and more certain to succeed, etc. Looking at change of bracket, other changes to improve clearance, QC regarding weld inspections before shipment, everything on the table. If we need to change design aspects, will do so. If we simply put too much in the tunnel, more than Mazda ever intended, not sure what we do about that but asking the questions.

So, what I can say guys is looking deep into it from every angle, will make any improvements we can rationally figure out will be helpful. If you are having issue with it, please do work with our sales team to document what is happening and they will work with you. Thanks,

rherold9

26th May 2017, 10:50

Brian,

Thank you for the response. I'm glad you are aware and looking into the issue. I appreciate you taking the time to give us an answer. I know it's not easy with variation of everything I just didn't like people's answers on the forum. Looking forward if you all can figure something out.

I'll be installing the street header and HH next week. I'll be following your guide to the tee on the forums, specifically of using the connecting pipe to raise or lower the exhaust to not hit any braces and such. Hopefully I won't get the rattle

JTod

26th May 2017, 12:24

It's not an installation issue, it's a manufacturing issue. These are not difficult products to install by any stretch of the imagination. When I bang on my HH and it rattles internally it has nothing to do with installation.

I had four different mufflers on my car - RB, FM, Moss and GWR. Only one would not align properly so that the tips were evenly spaced up and down and front to back. The GWR - and no amount of slip joint adjustment would correct it. Again, a jig or manufacturing issue.

Super Josh

26th May 2017, 13:14

I am running a catless header, HH mid and stock muffler and it sounds really raspy. Does anyone think this is normal? Would an aftermarket muffler make it sound any deeper than the stock one? Or because an aftermarket one is more free-flowing and reduces the sound less would it sound even worse?

Thanks all,

Josh

Blutonic

28th May 2017, 00:57

I'm glad topics like this exist, gives me something to look out for next week when I buy Goodwin's RoadsterSport II exhaust and Helmholtz Midpipe. I have a completely stock exhaust and am very excited to up the ante a bit. The car is too damn quiet from the factory!

Pstone

28th May 2017, 07:56

Does anyone run the gwr header and super q with the factory midpipe? I'm planning on pulling the helmholtz this week. I've adjusted mine countless times since I kept being told it was an installation issue, but now I'm thinking it will always have a vibration no matter what.

aroundcorner

28th May 2017, 10:41

I'm running this setup. Sound level is 20-30% louder than stock, deeper note, but will drone particularly when cold. Install is straightforward but you must pay careful attention to the midpipe to Q connection since it is really easy to bend the stock flange and create a leak which will increase drone.

warthogdrifter

29th May 2017, 18:25

The solution might be buying a different mid pipe. It's a real shame and a waste of $500... I guess I'll be selling a hh soon lol.

JTod

2nd June 2017, 10:18

The solution might be buying a different mid pipe. It's a real shame and a waste of $500... I guess I'll be selling a hh soon lol.

Doesn't sound like Goodwin's statement:

"If you are having issue with it, please do work with our sales team to document what is happening and they will work with you"

is jiving with your experience...

warthogdrifter

2nd June 2017, 11:50

Doesn't sound like Goodwin's statement:

"If you are having issue with it, please do work with our sales team to document what is happening and they will work with you"

is jiving with your experience...
I tried and sent a video. I guess they couldn't hear the sound that I can because I was in a noisy shop. I'm going to try and make another video for them but I've been too busy to get the car off the ground. It's frustrating and I've already spoken with them multiple times since the original install.

Amoeba Culture

4th June 2017, 22:52

I'd like a follow up in regards to what can be done. I have no complaints about the drone and the exhaust doing its job, however I have been having the same issues as everyone else here with the rattling.

JTod

6th June 2017, 10:53

Indeed, we should keep this thread alive until some answers are forthcoming. The cold rasp and rattle my the car sound like crap when cold.

MrTeek

6th June 2017, 19:27

Does anyone have an issue with the full GWR setup giving a muted, metallic backfire 'pop' when shifting and applying gas? I just installed my GWR setup with header, mid, HH and it's driving me nuts.

I haven't been able to find much other threads about it, but it's better explained by the post here https://forum.miata.net/vb/showpost.php?p=7993796&postcount=10. Aka a metallic 'fart' sound.:cry:

Again, extremely annoying and disappointing sound from such an expensive exhaust. Anybody else experiencing this? Maybe this is something GWR can also look at from the manufacturer?

P.S. Not intending to hijack this thread just wanted to add to the list of GWR exhaust concerns...:wave:

E39S62

6th June 2017, 22:27

Does anyone have an issue with the full GWR setup giving a muted, metallic backfire 'pop' when shifting and applying gas? I just installed my GWR setup with header, mid, HH and it's driving me nuts.

I haven't been able to find much other threads about it, but it's better explained by the post here https://forum.miata.net/vb/showpost.php?p=7993796&postcount=10. Aka a metallic 'fart' sound.:cry:

Again, extremely annoying and disappointing sound from such an expensive exhaust. Anybody else experiencing this? Maybe this is something GWR can also look at from the manufacturer?

This phenomenon is extremely common and is discussed on a slew of threads here. Do a Google search for GWR backfire or pop and you'll find a trove of threads where people talking about their exhaust popping between shifts or when they lift off the gas to coast.

Some people cite the computer spraying fuel on the exhaust valves as a cooling measure causing unburnt fuel to go into the exhaust. Apparently the massive stock muffler does a better job of muffling these.

Others will tell you to check the gasket seal between the muffler and mid-pipe as a bad seal here will exacerbate this phenomenon. Brian waded into one of those threads years ago and it might be why he's mum here as it was a bit of a $#@$show.

With a rich tune it's even more obnoxious.

dunhamjr

7th June 2017, 15:52

an "easy" test to further confirm the issue being installation vs construction/manufacturing...

pull the midpipe out (yeah i know that sucks)
separate the two segments.
inspect all the hanger.
bang on the CAT section with your hand.
bang on the HH section with your hand.

are any hangers broken or does either section rattle now?
yes. problem exists in the item itself, construction or otherwise.
no. installation problem, try again and figure out what is not tight or the pipe is touching.

so IF i end up buying a HH from GWR, i am going to using it as a set of bongo drums in the living room for an hour or two to make sure the construction is not an issue.:rofl:

Brian Goodwin

7th June 2017, 15:59

Does anyone have an issue with the full GWR setup giving a muted, metallic backfire 'pop' when shifting and applying gas? I just installed my GWR setup with header, mid, HH and it's driving me nuts.

I haven't been able to find much other threads about it, but it's better explained by the post here https://forum.miata.net/vb/showpost.php?p=7993796&postcount=10. Aka a metallic 'fart' sound.:cry:

Again, extremely annoying and disappointing sound from such an expensive exhaust. Anybody else experiencing this? Maybe this is something GWR can also look at from the manufacturer?

P.S. Not intending to hijack this thread just wanted to add to the list of GWR exhaust concerns...:wave:

Every brand of exhaust we offer will unmask the pops, which were ALWAYS there with the stock system. Doesn't matter if you get our Racing Beat setup, or RoadsterSport, or Magnaflow, PPE Header and Midpipe combo, etc. As noted by dunhamjr, if your car is running rich you hear these a lot more...but even brand new and perfectly tuned these are NORMAL...and you hear them if you have a highflow exhaust. There are numerous variables but even brand new the NC had these whether your human hearing could pick it up or not with the stock system. Sample YOUTUBE video (https://www.youtube.com/watch?v=HCVNK2vCHII) with half a dozen NC exhaust brands, all pop more or less depending on how free flowing they are.

As noted by somebody else already, you just did not hear them before because they were so much more 'muffled' with the massive stock muffler. The more you raise the volume and open the exhaust system by changing to more free flowing setup, the more you will notice these...some of you for the first time. This unmasking of the pops is not unique to Miata, it is EVERY sports car. Go on Youtube and search 'sports car exhaust pops' and hear some variation of it with every sports car ever made. Funny story about exhaust 'pops', when the good folks at BMW designed their MINI they wanted to make it feel less econobox and more sports car and they included a highflow exhaust from the factory so consumers could hear the fun pops from the first test drive (search MINI exhaust pops on Youtube for many samples...like THIS ONE (https://www.youtube.com/watch?v=mji*zADWf4VM)....or THIS ONE. (https://www.youtube.com/watch?v=U7sBEHm9e1c)).

Brian Goodwin

7th June 2017, 16:04

Indeed, we should keep this thread alive until some answers are forthcoming. The cold rasp and rattle my the car sound like crap when cold.

Part of the math with Helmholtz is temperature.

TSIGOS

7th June 2017, 22:29

Brian,

I have to chime in here because none of the videos demonstrate the pops when upshifting. The videos that you uploaded are all what I would consider a burble and not a backfire-like pop when upshifting. Nor do any videos on your website demonstrate the same. I have tried everything I could think of to eliminate or reduce the occurrence of the upshift pop without success. Very frustrating to say the least.

Brian Goodwin

8th June 2017, 09:04

Brian,

Think about it...the exhaust system cannot make fuel....it can just let that sound out if your car is dumping it into the exhaust on shifts. Some is normal and in many threads here over the years like THIS ONE (https://forum.miata.net/vb/showthread.php?t=609424&highlight=shift+pops), and THIS ONE (https://forum.miata.net/vb/showthread.php?t=540238&highlight=pops+exhaust+shift), and THIS ONE WITH SOME EXPLANATION BY TUNER JOE (https://forum.miata.net/vb/showthread.php?t=580419&highlight=pops+exhaust+shift).

The more open exhaust system you add, the more you hear it...but the exhaust is not causing or otherwise making fuel explode in the exhaust. Lot's of good tutorials on this all over the net to explain the basics, like THIS ONE on YOUTUBE. (https://www.youtube.com/watch?v=bgS3PA5r0vY) Plenty of descriptions of same behavior in many threads here for every brand of exhaust (https://forum.miata.net/vb/showthread.php?t=580419&highlight=pops+exhaust+shift). If you have more than the normal pops sometimes it is the tune, sometimes dirty injectors, sometimes bad EGR or dirty TB or bad PCV, .....but it's not the exhaust system downstream magically making fuel and making it explode. You have heard the classic "don't shoot the messenger" right? Well, the exhaust system is the messenger for what is going on upstream at your motor. You list 'Dynotronics Tune' in your signature and I have linked you to where Joe says he can turn that off; so when you say you have 'tried everything', does that include actually talking it over with your Tuner? Kids sometimes intentionally knock out all the cats and then map it rich to release bangs of fuel on upshifts (another YOUTUBE HERE) (https://www.youtube.com/watch?v=VTFl76wMpzM)....not recommended but it will hopefully help you understand your car may be running rich, and either way it's extra fuel you hear and the exhaust system does not cause your car to dump fuel between shifts.

Cookie Monster

8th June 2017, 12:35

Brian,

To be fair, in that video that Brian posted, there was no upshifting at all so obviously you're not going to hear any pops.

I don't get it... you bought a sports car, put an aftermarket exhaust on it, and then complain it pops? If you don't like it, go back to stock? :dunno:

I love the pops. Mine bangs out pops on upshifts even with the stock midpipe. I'm extremely tempted to get the Racing Beat catless straight pipe and ask Dynotronics to see if I can get bigger pops/flames, but the car is already way too loud and I already got a ticket for my exhaust a few months ago so probably not a great idea.

Either way, I don't think blaming Brian for the popping is fair. I am not commenting on this rattle issue with the HH stuff since I don't have any experience either way, but come on.

Chuck H

8th June 2017, 12:47

With a rich tune it's even more obnoxious.

Agree with these guys. Any free-flowing exhaust on a manual transmission NC makes those pops on upshifting. You can also get them just letting off the gas to idle then getting back on the gas. It's a fueling thing, nothing to do with the exhaust. The only difference is that the stock exhaust is so quiet that you can't hear the pops.

My setup is a PPE long tube header, PPE midpipe, and Enthuza dual exhaust and I get the pops on almost every upshift. They're actually worse when just "granny shifting" then when winding it out. If you shift fast enough, they're not as obvious either, but when you're just doing relaxed cruising around town, they seem to be the most pronounced. :dunno:

I think a tuner could minimize them if that was one of your tuning goals. Might effect throttle tip-in performance, though.

rherold9

8th June 2017, 13:32

Idle and revs to 4k so far I have no issues with rattling. I have not been able to drive on the setup except a quarter mile while I'm troubleshooting rear top mount rubbing issue..

I used the clamp recommended in this thread. Nothing rattles when shaking the exhaust when on the car.

On another note. foly huck. The Street Header + HH + Street Single sounds amazing just to a few 4k revs in car with windows down in my garage. It's loud but not terrible. It also has a really great tone. The tone is what I was looking for. Not ricey which is nice. I literally cannot wait until I can really drive this...

JTod

8th June 2017, 13:32

Part of the math with Helmholtz is temperature.

What is causing the internal rattle that several of us have been experiencing?

Pstone

10th June 2017, 13:02

Helmholtz readjust number 6. I pulled the exhaust hanger off the car that holds the center rubber hanger. Heated it up and bent it 3/4" away from midpipe. I also cut off the end of the center hanger from the midpipe. If I pull the exhaust hard, these were the only two remaining spots that would come in contact. I also picked up this lap joint clamp to help stop any exhaust leaks.

http://www.jegs.com/i/Dynomax/289/33226/10002/-1

Under 50% throttle I could hear some blow by. I tested the whole midpipe off the car and had 3 small exhaust leaks. 2 in welds, and one on the cat. I have already had some of the welds rewelded since they started to fail after a couple thousand miles.

Letting JB weld setup on the exhaust leaks I patched. I'll report back if the repairs resolve my issues. I yanked on the exhaust and couldn't get it to touch any part of the car. If this doesn't work, then I'll get a custom midpipe made.

Super Josh

10th June 2017, 14:52

I tested the whole midpipe off the car and had 3 small exhaust leaks.

That's an interesting approach, do you mind if I ask you how you managed to test it off the car?

Josh

tulhutch

11th June 2017, 23:03

I just installed GWR Hemholtz mid pipe and roadster street muffler,. There was two points that initial installation caused rattle. One was the connection point bolt needs to be twisted upward to almost difficult to tighten down. The other is with the stock cross braces needed to be stepped on and bent just a little for the pipe to clear underneath. After those two corrections very good results with excellent exhaust sound. Have not put headers on yet[emoji57]

tulhutch

11th June 2017, 23:43

Need to clarify that my modification was on a 2006 MX-5 not a BMW.

warthogdrifter

12th June 2017, 03:46

Part of the math with Helmholtz is temperature.

Thus, the math is just not working optimally before it gets to temp....and nothing that can be done about it, nature of the beast. We could spec the valve to work when cold...but then it would not be optimal when car reaches normal temp. So, obviously we need to spec normal operating temp for the math to work on long drives, etc. Here on the west coast we get to temp in just about five minutes of normal driving, those in the midwest winters will take a lot longer.
I understand what you are saying. Every exhaust system I've ever seen has needed a warm-up, but I've never heard one sound almost broken before it reached temperature. I would have opted for your RS mid pipe if I had known.

warthogdrifter

12th June 2017, 03:49

The pop question is a little off topic and completely normal.

warthogdrifter

12th June 2017, 04:09

I'm not to knock your product. I wrote a good initial review and I still stand by it. I just wish you were a little more honest about the HH, so I didn't have to waste my time troubleshooting a problem that couldn't be fixed.

My initial post:
https://forum.miata.net/vb/showthread.php?t=632728

rherold9

12th June 2017, 09:45

I'm waiting to actually put load on the car besides moving it around the garage, drive way, and a quarter mile on the street but I had none of these issues. I have a large storm channel curbing to get into my garage and I do not rattle with load, clutch held at engagement point for a second or two to get up them.

The brace mid to rear of the car looks like it could rattle but has not yet. It's close to touching. Not sure how people are having issues with the seal clamp bolt?

Are you sure you all are shoving that mid pipe piece in as far as you can? I sprayed some penetrating oil and pushed it hard in to get it to sit up more.

Only thing I'm worried about at this point is welds if people's are already having that issue...

Pstone

12th June 2017, 14:34

Well, none of my fixes helped the issue. Still get metal vibration between 3-4k rpms for the first 15 minutes. It's been 90 degrees in Minnesota lately, so it's not a temp difference compared to California causing the issue.

tulhutch

13th June 2017, 08:31

I meant to describe that this was on a 2006 MX-5, not a BMW mini.
Have you checked the light weight heat shield material above the mid pipe? I noticed that it comes unhooked easily and hangs down on or near pipe.

rherold9

13th June 2017, 09:43

Was able to drive the car about 20-30 miles yesterday. Not one single issue. Car sounds amazing. Literally no drone 3k rpm range even with a street single and street header. I'll need to hear it from the outside but so far it sounds good with windows up or down. I may try the race single once I hear it from the outside.

Side note: you can for sure feel the power difference for sure... even if it's running rich and still adapting it's got a tin bit more oomph.

JTod

14th June 2017, 23:45

Side note: you can for sure feel the power difference for sure... even if it's running rich and still adapting it's got a tin bit more oomph.

Hopefully your car remains rattle free but my HH rattle didn't start right out of the gate. It was a slow progression, not unlike the vendor's response to the issue on this forum :bang:

Chuck H

15th June 2017, 07:13

I know this is fairly basic troubleshooting, but has anyone taken the front and/or rear half of the HH midpipe off the car and shaken it, banged on it, etc. to see if they can isolate it to the pipe itself or something that it rattles against when installed?

That should help narrow it down to whether it's the cat, the resonator itself, the connection between the pipes, or a clearance issue when installed. :dunno:

Pstone

15th June 2017, 09:22

Yep, I've taken them off, apart, banged, shaked, can't get any vibrations. Double checked the super q and that was good too. Must be a certain frequency at 3-4k rpms that causes it. Wish I had a way to put load on the car and be under it to determine the issue.

My last ditch effort is to remove both factory chassis braces. I had spaced out the front with washers since it looked close to the header, but that didn't help at all either. If that doesn't work, I need to see if GWR can try shipping a new HH to test. Would rather not spend a ton on having a custom one made since I did spend $1700 for this full exhaust.

rherold9

15th June 2017, 09:42

Hopefully your car remains rattle free but my HH rattle didn't start right out of the gate. It was a slow progression, not unlike the vendor's response to the issue on this forum :bang:

That doesn't make me feel any better :rofl:

JTod

19th February 2018, 01:48

Slightly edited quote above - as a person with a rattling Helmholz I'm interested in what conclusions were made after this site visit? I've read references to a redesigned part but the unit shown on your website look just like mine.

Maurtis

19th February 2018, 10:58

I am still fighting an exhaust rattle too. I recently added a Max Power header and HH midpipe to my existing Super-Q. When I got it back from the installer there was a HELLACIOUS racket on both startup and heavy acceleration.

After some diagnosis and adjustments to nearby heat shields and with 500 miles on the setup the rattle has calmed to barely audible on cold startup idle but even after being warmed I still get a rattle on heavy acceleration. I spent a month crawling around under the car looking for issues but could not find anything new so I buckled and took the car to a nearby shop. I have the car at the shop right now but they cannot find anything making contact that would rattle on acceleration.

I am replacing my top soon so hoping the installer who is much more knowledgeable about Miatas than my local shop will have an idea.

I am perfectly fine with a rattle under heavy acceleration while cold, while not preferable I am fine with it if that is as designed. But a persistent Ebay-fart-can rattle any time I get on the throttle hard, that does not work for me. I would hate to have to start swapping out midpipes to diagnose the issue, but that might be where we have to go.

rherold9

19th February 2018, 13:25

So, I got the dreaded rattle. It was rattling on the factory braces. The stock hangers slowly stretched over time and we're hanging too low. I replaced the middle hanger with a polyurethane and no issues at all anymore.

JTod

19th February 2018, 13:44

My rattle seems to be internal to the HH, bang on it with your fist and hear a rattle without nearly enough movement for hangers to be an issue.

Pstone

19th February 2018, 15:16

I think mine has to do with the cat or it's shielding as well. I still get a rattle at mid to heavy throttle.

warthogdrifter

19th February 2018, 16:51

Mine has never gone away. Something inside my cat rattles like crazy from day one, but they wrote it off as they couldn't hear the sound. Now in getting a o2 code post cat. I changed the sensor and wire now I'm pretty sure the cat is failed component. Also super Q broke one of its supports at about 8k miles of use. I'm going to have it fixed at a local weld shop. Their warranty involves me shipping it back (at my expense) to CA so the factory can do the same thing. Ridiculous! 2/3 components have failed at about one year now I'm just waiting for the headers to break in some way.

warthogdrifter

19th February 2018, 16:56

I already advised my brother to buy exhaust for his ND elsewhere. He got an HKS and is super happy with it.

Mr Holiday

20th February 2018, 01:47

Part of the math with Helmholtz is temperature.

What valve?? The only valves I have seen in exhaust systems have been on motorcycles to alter the back pressure at different RPM's.
I thought the main reason for the HH is to eliminate droning?
Is there a temperature operated valve to open/close the HH???

Cheers

AZ Sun Lover

20th February 2018, 05:50

Hmm...

My first comment is about the Pops in the exhaust system. I found out if I shift below 3k RPMs I don't get any pops. Also when I shift above 3k RPMs if I slowly release the gas pedal between shifts I don't get any pops.

Exhaust mods to my 07 GT 6 MT, an Goodwin max header (w/ small runners) OEM mid-pipe with pre & post bungs welded in. (See link below) The header & mid-pipe were coated black by PPE. (After photo was taken) I then had a friend extend the O2 wires because they are SS and I don't trust my skills soldering SS to copper wires. The wires are rapped in high heat insulation with the rear one running behind the heat shield in the trans tunnel. The last third is an Magnaflow 16668 system modified by Jason @ Enthuza. I tried the full GWR system w/ the Q. I will just say it was not to my liking.
The OE mid-pipe cuts the volume so much more and no more P-0421 codes‼️ :jump: Lesson learned the hard way. :sad:
Plus GPS gear pulls are better with the OE mid-pipe. Blue Meanie can concur.
My .02 cents if you go back to the OE mid replace the OE resonator with an 5" round x14" Magnaflow and what ever muffler you like.

My experience,
AZ

https://forum.miata.net/vb/picture.php?albumid=943&pictureid=5978

Chuck H

20th February 2018, 08:58

Cheers

It's not a valve, per se. That's how Brian describes the Helmholtz effect. A Helmholtz resonator cancels out certain sound frequencies based on the volume of the chamber and the volume of the neck that leads into the chamber. But the effect also depends on the speed of sound in the air in the neck, which is temperature sensitive. So it's designed to cancel the drone frequency at normal exhaust operating temperature, not necessarily at cold start temperature.

JTod

20th February 2018, 11:33

Still looking for a response from Goodwin about whether the part was redesigned and why and what remedies there are for those with rattles...

Maurtis

20th February 2018, 14:33

I tried to video my rasp/rattle on throttle the other day, but the mic on my phone was not picking it up. Your video with the FM muffler picks it up better. Mine sounds like yours. It looks like I have a different cat on my HH midpipe, though, it does not have any shielding? Maybe they updated the design?

A link to your video for reference: https://www.youtube.com/watch?v=1t_81GEAgik&feature=youtu.be

Watching my own in-car videos from my phone, the exhaust sounds freaking awesome. Maybe I just need to wear ear plugs when driving to muffle the higher pitched rasple, LOL.

My local shop could not find any issues either :( They could hear it on the test drives, but could not find any contact points for an external rattle. I ordered one of those larger Dynamax clamps just in case it helps at the slip joint and will hopefully get a better diagnosis when I take it to someone who really knows Miatas, instead of my local shop.

warthogdrifter

20th February 2018, 14:38

A link to your video for reference: https://www.youtube.com/watch?v=1t_81GEAgik&feature=youtu.be

My local shop could not find any issues either :( I ordered one of those larger Dynamax clamps just in case it helps and will hopefully get a better diagnosis when I take it to someone who really knows Miatas, instead of my local shop.The larger clamps are a waste of time. I tried them and had no improvement.

warthogdrifter

20th February 2018, 15:03

Hmm...

Exhaust mods to my 07 GT 6 MT, an Goodwin max header (w/ small runners) OEM mid-pipe with pre & post bungs welded in. (See link below) The header & mid-pipe were coated black by PPE. (After photo was taken) I then had a friend extend the O2 wires because they are SS and I don't trust my skills soldering SS to copper wires. The wires are rapped in high heat insulation with the rear one running behind the heat shield in the trans tunnel. The last third is an Magnaflow 16668 system modified by Jason @ Enthuza. I tried the full GWR system w/ the Q. I will just say it was not to my liking.
The OE mid-pipe cuts the volume so much more and no more P-0421 codes[emoji844] :jump: Lesson learned the hard way. :sad:
Plus GPS gear pulls are better with the OE mid-pipe. Blue Meanie can concur.
My .02 cents if you go back to the OE mid replace the OE resonator with an 5" round x14" Magnaflow and what ever muffler you like.

My experience,
AZ

https://forum.miata.net/vb/picture.php?albumid=943&pictureid=5978Your picture link does is not working could you try to upload it again?

warthogdrifter

20th February 2018, 15:08

https://photos.app.goo.gl/XDpepJ8J7HbDS1Ln1

https://photos.app.goo.gl/5vRifraPuAmXYIBc2

https://photos.app.goo.gl/4gwJbAxpivK2VlS83

Pics of the broken super Q

warthogdrifter

20th February 2018, 15:20

I like the weld O2 bunges on the OEM mid pipe idea. I'm going that route. Apparently I lack the skill to do a "customer install" to make the HH not sound like garbage internally. I can manage to install a T700-GE-401C engine into a MH-60R Seahawk at work, but can't seem to master a pipe and 4 bolts. It's really insulting that the vendors response was we are all essentially "doing it wrong"

LqdSilver

20th February 2018, 15:36

Mine came from the clamp. On start up, it would rattle when cold then once warm rattle is gone. I stuck a tiny piece of metal from an old bracket in between pipe and clamp and have not had the rattle since.

dunhamjr

20th February 2018, 16:41

Your picture link does is not working could you try to upload it again?

hmm. link works for me.

i was just posting AZ's pics in another thread about this same idea... maybe these links work for you.

https://dl.dropboxusercontent.com/s/4j6z8uofst05069/exhaust-oem%20midpipe%20o2%20bung-user49345_pic5976_1308179189.jpg

https://dl.dropboxusercontent.com/s/69l82atqw5nm361/Exhaust-oem%20midpipe%20o2%20bungs-user49345_pic5978_1308179189.jpg

JTod

20th February 2018, 16:44

You wouldn't know it from the product page or the lack of vendor response in this thread but apparently the HH has been redesigned - pics on entry 201 on this thread show the support installed in the middle rather than the end of the tube:

https://forum.miata.net/vb/showthread.php?t=589527&page=9

warthogdrifter

20th February 2018, 17:43

hmm. link works for me.

i was just posting AZ's pics in another thread about this same idea... maybe these links work for you.

https://dl.dropboxusercontent.com/s/4j6z8uofst05069/exhaust-oem%20midpipe%20o2%20bung-user49345_pic5976_1308179189.jpg

https://dl.dropboxusercontent.com/s/69l82atqw5nm361/Exhaust-oem%20midpipe%20o2%20bungs-user49345_pic5978_1308179189.jpgI see them now thanks a bunch

Maurtis

20th February 2018, 19:06

https://forum.miata.net/vb/showthread.php?t=589527&page=9

Yup, that is how mine looks. I ordered mine last month (01/2018). No shielding around the cat.

warthogdrifter

20th February 2018, 22:27

I knew it was my cat from day one. It's really aggravating they denied the issue and had the part re worked without ever getting back to me.

JTod

21st February 2018, 00:21

I can manage to install a T700-GE-401C engine into a MH-60R Seahawk at work, but can't seem to master a pipe and 4 bolts. It's really insulting that the vendors response was we are all essentially "doing it wrong"

No amount of midpipe manipulation will result in even fore to back and top to bottom exhaust tips on my Super Q, it was clearly jigged wrong during welding or something. I've had four mufflers on my car - Cobalt, RB, FM, and Super Q and only the Super Q couldn't be installed with squared exhaust tips. To say nothing of the ratttling HH and now I have some fumes emanating from the engine compartment which I suspect is a GWR header leak due to a bad weld. $1,500+ well spent :mad:

Mr Holiday

21st February 2018, 01:16

Chuck;
Thanks for clearing that up. Brian's description had me wondering if there was some kind of mechanical valve in the HH that was giving the guys problems.
Now I know that's not the case.

Thank you

AZ Sun Lover

21st February 2018, 05:13

hmm. link works for me.

i was just posting AZ's pics in another thread about this same idea... maybe these links work for you.

https://dl.dropboxusercontent.com/s/4j6z8uofst05069/exhaust-oem%20midpipe%20o2%20bung-user49345_pic5976_1308179189.jpg

https://dl.dropboxusercontent.com/s/69l82atqw5nm361/Exhaust-oem%20midpipe%20o2%20bungs-user49345_pic5978_1308179189.jpg

Hmm...Thanks for the help, I went to my wife's laptop and the photos worked for me...?

I see them now thanks a bunch

I put to 02's straight up because they are hidden from the smog police plus they won't get ripped off by running over something. Stranger things have happened!
If you cut off the two "L" brackets from the OE header then weld them on the aftermarket header, then attached the upper half and part of the lower half of the heat shield (you need to do some trimming of the lower part of the heat shield.) The smog police can not see that the OE header has been replaced! I was gonna to do that but here in AZ they only depend on the cars computer / OBII system and don't do a visual check. OBI systems still get a visual check.
I also move the tab 180 on the heat shield between the ABS brake system and the header to move it closer to the header.

warthogdrifter

21st February 2018, 23:31

Hmm...Thanks for the help, I went to my wife's laptop and the photos worked for me...?

AZI am going to get the O2 bunges welded on Friday I'll let you know how it goes. If there is enough clearance to have them go straight up I will literally use your pic as reference when I get mine done. I'm going to pull off the HH tomorrow and make sure your locations will work for me.

AZ Sun Lover

22nd February 2018, 02:27

I am going to get the O2 bunges welded on Friday I'll let you know how it goes. If there is enough clearance to have them go straight up I will literally use your pic as reference when I get mine done. I'm going to pull off the HH tomorrow and make sure your locations will work for me.

1. Pull off the RS mid, remove the 02's from the mid.
2. Losely install the OE mid. Look closely at where my 02's are placed in the photos.
This is where you mock up / place the 02's where they clear. Remember when the OE mid is installed fully the bottom of it will be flat and level. The front 02 should be where it is in the RS, I used a sharpie to mark and pretended the sharpie was an 02.
3. The rear is just as easy, just placed the rear 02 between the trans and the transmission tunnel, straight up. You should have more than enough room. I worried that the 02 might hit, but remembered the transmission and motor torques along with the exhaust system. There's absolutely no way the 02 will hit anything if installed correctly. The rear 02 went where the impressions in the heat shield cross.
4. Remove and drill with a step drill bit. I drill the front 1st then emptied the shavings out the front. You don't want the metal shavings going into the cat, front and rear.
The rear is just as easy but you will get into the glass insulation. After you have drilled the rear you will need to trim some of the tin back to be able to weld in the bung. I used a small hammer to form the metal in a little.
5. Just made sure the mid is flat and level and the bungs are welded in level too! (The front one can lean back a little for more clearance if need be.)
6. I'm 100% sure you will be happy with this mod‼️
As I went from hating the exhaust system to loving it. :D
Again if the system is still a bit noisy just replace the OE resonator with an 5"x14" Magnaflow part # 12866 and I have a spare one if you want one. Don't ask.
Please do let me / us how you like it!
I can take photos from under the car to see how i routed the 02 wires. I routed the wires up and around the right front brake line. You will see when you are under the car. This pulls the wires right to the body of the car and away from the header and exhaust. No wires get any closer to the heat than where you plug them together.
Trust me I had a lot of issues myself using some parts that didn't fit and or were trash! I actually sold my first header because of all the issues I was getting.
After many sleepless nights and laying under the car for hours and taking to many people I decided to give it a second shot. I will say the RS header is one of the best I have ever seen and or installed.
Back in the 80's I installed a factory Datsun comp header in a 78 280-Z. But that damn thing cost me over $750 back in the day. Plus I had to buy a new head to fit the header. 240-Z had a larger square port and flowed better than the round port of the 260 & 280 Z's. With the cam and head work it sounded like a 327 until it came off the cam. God that car was fun but a pain to find gas that wouldn't ping in our hot AZ summers. It ran like a two stroke that kills mosquitoes at idol or the exhaust tips pure white.

augie05

22nd February 2018, 17:15

I just got mine installed today and was very happy until I saw this thread. It arrived yesterday from GWR and I had it installed by a muffler shop today.

Any idea what percentage of these mid-pipes are having this rattle or other issues??

I can't image GWR continuing to sell a product if it has know issues as identified in this thread. I have been pleased with other GWR products but this has me really concerned.

phoboy

22nd February 2018, 17:30

There were a few design changes to the mid-pipe and chances are you got the new one, so you may not experience the same issues.

warthogdrifter

22nd February 2018, 17:31

I just got mine installed today and was very happy until I saw this thread. It arrived yesterday from GWR and I had it installed by a muffler shop today.

Any idea what percentage of these mid-pipes are having this rattle or other issues??

I can't image GWR continuing to sell a product if it has know issues as identified in this thread. I have been pleased with other GWR products but this has me really concerned.It looks like he already addressed the issue and left the early adopters out to dry. The current version is redesigned. The HH chamber was stupidly braced right at the neck before and it looks like they did away with the cat shielding. My cat rattles like a tin can and looking at the redesign I bet it's because that shielding. Just know unless something catastrophic happens to your new pipe the vendor will try everything to get out of helping you solve a claim. If I could go back in time I'd stay far away from anything goodwin. I thought I'd be a getting quality made in the USA product. What I ended up with was junk and being misled by a good sales pitch.

warthogdrifter

22nd February 2018, 17:49

I just got mine installed today and was very happy until I saw this thread. It arrived yesterday from GWR and I had it installed by a muffler shop today.

Any idea what percentage of these mid-pipes are having this rattle or other issues??

I can't image GWR continuing to sell a product if it has know issues as identified in this thread. I have been pleased with other GWR products but this has me really concerned.My one year old super Q already broken and HH was broken from day one. Going to a local welding shop to rig up O2 sensors on the factory mid and fix the Super Q. The worst part is I bought this full exhaust kit on my last month of deployment. 8 months at Sea and I was really excited and looking forward to the goodwin full exhaust... What a joke! On a positive note the catless headers are really nice and holding up still. So, that means I only wasted $1000 of my $1500 dollars. I wish I didn't sell my flying Miata muffler... it was old and heavy, but well made. Also, it sounded way better than the Q paired with the factory mid pipe. Back then I thought it sounded worse in comparison, but I now realize it was the HH that made everything sound like crap. 280608

Maurtis

22nd February 2018, 19:09

My one year old super Q already broken and HH was broken from day one. Going to a local welding shop to rig up O2 sensors on the factory mid and fix the Super Q. The worst part is I bought this full exhaust kit on my last month of deployment. 8 months at Sea and I was really excited and looking forward to the goodwin full exhaust... What a joke! On a positive note the catless headers are really nice and holding up still. So, that means I only wasted $1000 of my $1500 dollars. I wish I didn't sell my flying Miata muffler... it was old and heavy, but well made. Also, it sounded way better than the Q paired with the factory mid pipe. Back then I thought it sounded worse in comparison, but I now realize it was the HH that made everything sound like crap. 280608

Wow, that was an early one! Mine has the shieldless cat and the HH chamber support is in the middle and not at the neck now.

Armand in Houston is replacing my top next Friday so I am hoping he can help pinpoint the issue on mine. He installed a customer's setup a couple weeks ago and from the video posted it was completely rasp/rattleless, his brand new install sounded much better than mine with a couple hundred miles on it.

If it needs to be a warranty replacement then that is fine, I just want a resolution. That rasp/rattle under acceleration sucks the joy out of the exhaust note.

Maurtis

22nd February 2018, 19:11

I just got mine installed today and was very happy until I saw this thread. It arrived yesterday from GWR and I had it installed by a muffler shop today.

Any idea what percentage of these mid-pipes are having this rattle or other issues??

I can't image GWR continuing to sell a product if it has know issues as identified in this thread. I have been pleased with other GWR products but this has me really concerned.

I would not worry at all, from what I have heard some sound great from the start. I bet those of us with issues are in the minority, just a vocal and frustrated bunch :D

Grats!!!

warthogdrifter

22nd February 2018, 20:14

I would not worry at all, from what I have heard some sound great from the start. I bet those of us with issues are in the minority, just a vocal and frustrated bunch :D

Grats!!!At least our vocal frustration resulted in a positive change. Now future enthusiasts will buy a newly redesigned HH that isn't garbage from day one. We got burned so you wouldn't have to be. For my next Miata (ND) I'll be sticking to Japanese parts for my Japanese car.

JTod

23rd February 2018, 00:07

At least our vocal frustration resulted in a positive change. Now future enthusiasts will buy a newly redesigned HH that isn't garbage from day one. We got burned so you wouldn't have to be. For my next Miata (ND) I'll be sticking to Japanese parts for my Japanese car.

Goodwin has posted to the forums 25+ times this week but sure can't seem to find his way to this thread. The silence is damning and deafening and should provide an indication to others about that company's after sales support.

At a minimum they should pay your local welder to fix the broken weld on your Super Q - I suppose their position is that you hung it wrong.....:bang:

warthogdrifter

23rd February 2018, 01:41

At a minimum they should pay your local welder to fix the broken weld on your Super Q - I suppose their position is that you hung it wrong.....:bang:They wanted me to ship it back to California in the box I no longer have. Shipping would cost me around $140. I know because I've sold a muffler to someone in CA.

Check out this email they sent:

"Thanks for the photos, in order to have the factory repair this we'll need to have you ship that back to them. They will perform the repair and polish the muffler up before shipping it back to you. Please send us tracking as soon as you do so we can help expedite the process."

My reply:

"I do not have the original box it came in any advice on shipping? Also, what would be done at the factory? If it's as simple as welding a new brace next to the broken it might be cheaper to do that locally."

Mr Holiday

23rd February 2018, 01:44

With that being said, what vendor/vendors would you use to purchase a full catless system to the NC?? I don't want something too loud.

Cheers

AZ Sun Lover

23rd February 2018, 04:03

I would like to know how many are getting Code P-0421 with their RS mid?

The first time I installed the header and exhaust system I was getting this code a few times a week and for the life of me I could not figure why I was getting this code when everyone else were saying "No issues here or Not with mine, etc..." I was even told I installed it wrong! WTF :eek: Then I would get a few PM's and the owner would tell me they were having the same issue, but they didn't want to say anything because of retribution. Everyone thought it was because I had Jason build my mid-pipe but they didn't know it was an RS mid. After I started having issues I did have Jason build me a mid but he used the same cat that was in the RS mid. I then sold the RS mid & 1st gen Q. I purchased the mid and Q from a owner in Sun City because his wife told him no way he was doing anything to her car, the mid & Q were new. I then ordered the header and wires. The front wire was to short and the rear fell apart. They were sent back and I was refunded by Goodwin. RB made the wire extensions and there is no way to get a refund from RB. A lot of vendors don't do enough testing before they start selling to the public, RB doesn't even test fit before they sell to the general public! :realmad:
I sent the wire set back to Jason because he thought he might be able to fix them, he has an A&P license along with his welding skills. He is a great guy!

Pstone

23rd February 2018, 10:29

They wanted me to ship it back to California in the box I no longer have. Shipping would cost me around $140. I know because I've sold a muffler to someone in CA.

Check out this email they sent:

My reply:

No response after that coms went dark.
They did the same thing to me when they claimed to try and help with the original HH issue. They claimed to hear nothing in a video I sent them and coms went dark. They pretend to help you then ignore your follow up emails.
Same with me. It was cheaper to have a local welding shop fix the weld cracks and brace the helmholtz chamber. Unfortunately the rattling still persists. There's still pinholes in the header and super q welds as well. I'm ordering new wheels and and brakes this month, so I'll be looking to go through a different vendor.

I wonder if I can buy a new helmholtz midpipe, then ship my defective one back in the same box for a refund.

TSIGOS

23rd February 2018, 11:16

Same with me. It was cheaper to have a local welding shop fix the weld cracks and brace the helmholtz chamber. Unfortunately the rattling still persists. There's still pinholes in the header and super q welds as well. I'm ordering new wheels and and brakes this month, so I'll be looking to go through a different vendor.

I wonder if I can buy a new helmholtz midpipe, then ship my defective one back in the same box for a refund.

Same here. Had the cracked brackets repaired locally but still have the rattle when accelerating (and there is no evidence that of anything touching or any misaligned install - inspected by me and 2 different local installers). It is either an internal buzzing or the midpipe cat shielding.

JTod

23rd February 2018, 11:38

I wonder if I can buy a new helmholtz midpipe, then ship my defective one back in the same box for a refund.

I imagine I'm going to have to pull my header and check it for leaks. Not a trivial task and not something I wanted to do twice. Obvious QC issues with these exhaust parts but to hear Goodwin tell it none of us know how to secure a nut and bolt or hang a muffler.

Kerney

23rd February 2018, 16:58

I was debating a full Goodwin exhaust but Im now rethinking. I read the warranty but I guess that is fairly useless which is disappointing. There was another thread on a dead cat on their catted header tough not to read into this. I work in the automotive field so I understand mechanical things break especially early production. The difference is in how a company handles things. We bought a Honda that had known tranny issues and they warranted a new transmission on our car that had over 100k miles. We've bought 4 Hondas since.

Im just not sure what other options I have as it seems to be 80-90% goodwin on the forum and im always that guy who has issues.

dunhamjr

23rd February 2018, 17:11

Goodwin obviously still makes a good product, even if there are some issues here and there.
They have sold a ton of exhaust product that have no problems, or have easy fixes.
The bad thing is we here from unsatisfied people a LOT more than happy customers.

For other options.
Depending on your goals, reconsider if you even need a full exhaust.

The OEM midpipe is a fairly good piece to stick with if you stay NA.

As for the header, there are other makers. Maybe not as well known on this forum.. but at least consider some of the known ones... racing beat, ppe, obx, and tomei. I am sure there is a brand I am missing. Also consider that MAYBE you have a good fabricator locally that could custom fab you a setup.

For the rear muffler there are tons of options.
Some that I can think of... magnaflow, local built custom, enthuza, cobalt, tomei, racing beat, flying miata, mazdaspeed/dc... and likely many others.

I was not avoiding Goodwin in any way. I just wanted to spend a little less money and wanted a quieter low/no drone option.

So I am going with a Tomei header, OEM midpipe with o2 bungs added, and an Enthuza Single muffler.

Amoeba Culture

24th February 2018, 16:16

I had to chime in because I thought I was the only one having issues with the V1 HH system. The new design looks like a huge improvement. The product itself is amazing, doing an excellent job of being loud when you want and having no cabin drone. I only had installed my max ceramic headers and HH system just a little over a year ago and 5,000 miles later the welds began to form a crack all around the cat and the HH chamber. I have always had a good experience with Goodwin, but I wasn't so pleased with the failure of the V1 midpipes , and the customers who bought the V1 systems being left out to dry. My friend’s mechanic is a welder and he welded back my cat all around and added a bolt so that the HH chamber isn’t hanging on its own and does not form cracks all around again.

http://i64.tinypic.com/2nrqbr9.jpg
http://i65.tinypic.com/2zz3fgi.jpg
http://i63.tinypic.com/2qs2ws9.jpg

Brian Goodwin

24th February 2018, 22:32

Don't understand the choice here, we have warranty service on these guys, contact us during the week.

Welding BOTH ends of helmholtz can will guarantee failure....because it does not account for necessary differential heat expansion. That's why we don't have it welded at both ends like you have done here with that nut.

Farther

25th February 2018, 01:20

Don't understand the choice here, we have warranty service on these guys, contact us during the week.I was looking to purchase one of these but now I am getting scared off. Just to make this as transparent as possible, does the warranty include return shipping and what is the warranty period?

Cypher

25th February 2018, 06:29

Well, I bought one here in the UK last year and so pleased with the effect. When driving under normal acceleration it's better than OEM, however drive it like a boy racer and from 3000rpm to 3500rpm it sounds tinny. As this is only for a few seconds I can live with it.
Perhaps when I have a few more miles driven (only done 1500miles) this may deaden the "waspiness" sound.

John

Brian Goodwin

25th February 2018, 09:11

I was looking to purchase one of these but now I am getting scared off. Just to make this as transparent as possible, does the warranty include return shipping and what is the warranty period?

Warranty is for life, and like most products you send it back to the maker if repair needed....and they cover the shipping back to you.

warthogdrifter

25th February 2018, 13:30

I was looking to purchase one of these but now I am getting scared off. Just to make this as transparent as possible, does the warranty include return shipping and what is the warranty period?

Let me start off by saying I was in the wrong here. I was trying to get my HH warrantied about 7 months ago. Because of a failed email I thought I was left high and dry. In reality it seemed like I never got back to Good-Win's team and they where waiting for a response that never came. I have been talking with Brian and he is making everything right. They are sending me a new HH to replace my defective unit.

I had become so jaded over this ordeal, but in reality I really do love everything I have ordered from him. I am still using the max headers and the super Q just needed a spot weld at a local shop. I am looking forward to having a HH that doesn't rattle because it really does cut drone. The OEM mid pipe is a lot more quiet, but I can feel the loss in top end power and a bit of drone.

Farther, have confidence that you will get a good product. Mine was just an unlucky bad apple. Even though it rattled the whole time I still used it for a year because it cut the drone down so much. That alone should say everything!

I stand by my initial review of the Good-Win products.

Here is my initial installation thread with review:

https://forum.miata.net/vb/showthread.php?t=632728&highlight=warthogdrifter

Pstone

25th February 2018, 13:35

Hopefully he'll be reaching out to the rest of us as well for a replacement of our rattling HH midpipe.

Brian Goodwin

25th February 2018, 15:40

Hopefully he'll be reaching out to the rest of us as well for a replacement of our rattling HH midpipe.

Just one page back I wrote: "we have warranty service on these guys, contact us during the week." Seriously, please contact us this week, if three people contact me on same issue that gives me vast leverage with the factory to make sweeping solutions. Right now over 1000 of these sold and total warranty count by the factory is well under 10 spread over several years, half of those were early crack issues the factory considers resolved with stronger welds around helmholtz can and cat connection, etc. No reports that I know of any issues with latest version, but any earlier editions with continuing issues should be brought to our attention.

Note we don't have a system tied to screen names, need real people to reach out to contact us as real people so we can solve whatever real issues they have. PMs also not a great option, busy season now and our highest priority is taking care of customers contacting us direct, ONE CUSTOMER AT A TIME, which consumes most our time and often means we cannot parachute back into the forums for days at a time where a PM might be waiting. I have given my crew vast power to solve customer issues and maximize customer happiness...please give them a shot to prove it.

Thanks,

Maurtis

25th February 2018, 17:01

Thanks,

Thanks for the reply, Brian. I have been working with your support guys and they have been great about giving me suggestions and things to try.

I have not been able to locate the issue from my driveway and my local shop could not find anything physical either. I am hoping the shop installing my new top next week who know Miatas can help get a definitive answer on the cause, be it an installation issue or something internal. I will definitely let the support team know one way or the other.

Thanks!

Farther

25th February 2018, 21:27

...like most products you send it back to the maker if repair needed...I guess I am spoiled by Amazon. Free shipping and if I have an issue with their product, a UPS guy picks it up and it goes back to the vendor, all on their dime both ways.

JTod

26th February 2018, 16:13

So if a person sends back a rattling V1 HH does the factory reposition the bracing to the current version? Why, specifically, was the bracing position changed? Broken welds?

Maurtis

4th March 2018, 17:46

Thanks for the reply, Brian. I have been working with your support guys and they have been great about giving me suggestions and things to try.

Thanks!

Update, the shop that did my top install (thanks Armand!!!) heard the rasp/rattle right away and did some diagnosing. The rubber mallet test did not turn up any noises from the exhaust but DID cause my X brace to reverberate pretty badly. Looks like one of the welded nuts that the brace mounts to has broken its internal weld. I REALLY hope that is the source of my raspiness.

Until I can get the car to a shop that can cut that nut out and weld a new one I think I am going to try to put some leftover Dynamat on the bottom of the brace. The thinking is that if I change the frequency the brace resonates at, if that changes the nature of my rasp/rattle then I found the culprit. Otherwise if there is no change then I need to keep looking.

jim dreiling

13th March 2018, 18:28

I just installed the Helmholtz mid-pipe. Here is my post, about what I found/did.
https://forum.miata.net/vb/showpost.php?p=8870353&postcount=24372

rherold9

13th March 2018, 22:16

The more I read, the more I see install error, at least for the new version, being the problem

kingjason

13th March 2018, 23:42

You most definitely have to turn this and tighten that to get them right. Not high on the list but eventually I may go catted header and HH mid pipe with stock muffler.

jim dreiling

14th March 2018, 02:02

The more I read, the more I see install error, at least for the new version, being the problem

The biggest problem is realizing how much the exhaust "Grows/expands", at temperature.

phoboy

14th March 2018, 13:16

Install is definitely a bit tricky. The mid-pipe's slip-joint is the key to everything fitting well. A good amount of soapy water helps keep it from locking up so you can more easily adjust it to connect to the muffler. To make things easier, I'd say the keys points are:

1) Lift whole car up to have enough room and to ensure everything is hanging in neutral positions.
2) Plenty of soapy water on mid-pipe slip-joint/hangers to more easily adjust/rotate it.
3) Second set of hands is a good idea to help hold the mid-pipe as you're trying to align it. Otherwise it's tough just relying on the hanger to hold it up as it tends to twist and rotate the mid-pipe.
4) Before tightening down everything, check the muffler tips to ensure they're even. Otherwise mid-pipe isn't rotated correctly.
5) After installed and tightened down, drive around and check for rattles. Go back, lift car and check for any contact issues.

warthogdrifter

15th March 2018, 12:19

I just wanted to post a little update.

My new midpipe had some weld bits inside the HH chamber. It was easy to shake everything out to insure there would be no annoying noises.

I really like how the new versions header to midpipe flange now has recessed mounting holes. This makes it so the springs aren't over compressed on install. Also, the cat has no shield to rattle (my original issue) and the HH chamber is now braced in the middle.

Install was super easy aside from a stud coming off the header. I had spares, so no big deal.

Immediately I noticed the lack of previous annoying rattle sounds. It sounds freaking great now! I was using the stock midpipe and I immediately noticed how much power I lost doing so. The top end rush is back and was very missed. FYI I have catless headers. I imagine the power difference wouldn't be perceivable between the HH and stock mid paired with OEM headers.

Lastly I had one of the two original extended O2 sensor wires go bad. I went ahead and ordered two new ones and this time I made sure to wrap them with heat shielding tape. As we all know the short extension they send you is way too short. Mine was so taught and even though I did everything I could it was way too close to the header. Definitely the cause of failure. I noticed Goodwin sells a longer 1st O2 extension for their PPE header. It is 25" and so much better than the crappy short version they try to push. I had plenty of room to properly route it away from the header. See my pics to see the better O2 wire.

Brian if you read this I know your website says you are on short supply of the 25" extensions. I'm sorry I told a white lie to get the better cable, but seriously the shorter of the short extensions is way too short! You are setting your customers up for failure with them. The 25" version should be the only version.

Check the pics to see the 100% better routing of the 25" O2 extension. 282123282124282125282126282127

phoboy

15th March 2018, 13:42

^ Glad you got your new HH! This thing is easily on my top 5 list of essential mods, so glad GWR was able to sort it out with you.

rherold9

17th March 2018, 09:47

Yup, I think all issues are sorted on the current HH and would highly recommend it. Almost going on a year with no issues. Had no issues with installation by myself on my garage floor. Just be sure you lube the mid connection and adjust the length accordingly. I had the muffler mounted up and then matched the mid to where the muffler should be and cleared everything. The hardest part was pushing the back half of the HH into the slip joint and holding it up in the air at the same time on my own. I would recommend a second pair of hands for ease, but for sure doable on your own.

The only thing I did do was as stated was replace the middle exhaust hanger with a polyurethane one as the oem one was sagging which caused the mid pipe to rattle on the braces

Mr Holiday

17th March 2018, 21:39

Where did you get the polyurethane hanger from??

Cheers

jim dreiling

19th March 2018, 17:35

Where did you get the polyurethane hanger from??

Cheers

Goodwin Racing.
http://www.good-win-racing.com/Mazda-Performance-Part/60-1095NC.html

Maurtis

19th March 2018, 18:00

Well, we THOUGHT it was my x-brace reverberating but after putting my car up on jack stands and climbing under it that was not the case. In fact, with my son revving the motor while I was under the car I could not localize the rasp/rattle/resonance at all. It sounds like my old motorcycle pipes that were attached with springs. The springs would vibrate at certain rpms and you had to give them a half twist to stop them from vibrating.

I took video with the camera at different spots along the exhaust to try and find where it was coming from: https://www.youtube.com/watch?v=czxroqsS97E

I sent the link to Goodwin Support and they are shipping me a new midpipe, hooray! Thanks Brian and company! I really hope the new midpipe solves the issue.

With the glass packed baffles in, the exhaust volume is just about where I wanted it to be. Once I can get the buzzing under control I will be so very happy :thumbs:

Mr Holiday

19th March 2018, 23:28

Thanks Jim!

Cheers

Maurtis

17th April 2018, 18:18

To follow up, I finally had the new replacement midpipe installed that Goodwin sent to me and it dramatically reduced the tinny rasp I was getting, you can really tell on cold startup in the morning.

I do still get some of the tinny rasp on acceleration (especially before it warms up), but apparently that is to be expected from a catless header and HH midpipe. But man, SO much better than it was before.

Huge thanks to GWR for following up with me and agreeing to send out the replacement! :D

cgorrie

17th April 2018, 18:28

Thanks Maurtis. Any chance you might have time to post up another YouTube of your exhaust sound with the newly replaced midpipe? I'm suffering from the exact same rasp that was evident in your original video. Disconcerting that there is still any sign of a rasp with the replacement pipe. :ohno: Thanks!

Brian Goodwin

17th April 2018, 18:38

The midpipe knocks down the drone, the sound absorbing packing in your muffler knocks down the rasp.

Consider bigger muffler if you have more rasp than you want, this midpipe is not designed to do anything about rasp, it's a drone solution.

Maurtis

18th April 2018, 12:02

Sure, I planned on making a video clip with driving samples and DB measurements of each of the different Super-Q baffles anyway once the new midpipe carbons up, so will post a new video soon.

The midpipe knocks down the drone, the sound absorbing packing in your muffler knocks down the rasp.

Consider bigger muffler if you have more rasp than you want, this midpipe is not designed to do anything about rasp, it's a drone solution.

Thanks Brian, good to know. I have the Super-Q with glass packed baffles now but if a different muffler is in order I can work on that later. If I spend another dime on my current exhaust system my wife will probably set fire to the car, LOL! :realmad::rofl:

Super Josh

18th April 2018, 12:45

The midpipe knocks down the drone, the sound absorbing packing in your muffler knocks down the rasp.

Consider bigger muffler if you have more rasp than you want, this midpipe is not designed to do anything about rasp, it's a drone solution.

I have a stock muffler with my HH and it's still quite raspy. What muffler would you suggest then Brian?

Cheers,

Josh

Brian Goodwin

18th April 2018, 13:04

I have a stock muffler with my HH and it's still quite raspy. What muffler would you suggest then Brian?

Cheers,

Josh

Stock muffler has really no packing, pure empty chamber attenuation design that just knocks down volume, so rasp coming down a highflow setup upstream is not captured well by stock muffler.
https://forum.miata.net/vb/attachment.php?attachmentid=41074&d=1178824790

Sound absorbing packing captures rasp, suggest our SuperQ (http://www.good-win-racing.com/Mazda-Performance-Part/60-13372.html) which starts with much smaller attenuation chamber roughly the size of that center chamber you see on stock muffler above....and surrounded each side by fully stuffed stainless mesh/fiberglass absorbing chambers. If you imagine just the center chamber above on that stock muffler is empty and the rest is stuffed with packing, that's essentially what the SuperQ has inside. Result will be a little MORE volume overall because SuperQ is a higher flowing design with bigger pipe in and out of it, but less rasp thanks to the packing.

cgorrie

18th April 2018, 13:54

Sure, I planned on making a video clip with driving samples and DB measurements of each of the different Super-Q baffles anyway once the new midpipe carbons up, so will post a new video soon.

Cool. I'll keep an eye out for the video. In the meantime, have fun with the carbon coating!

And Brian, I have the exact same setup as Maurtis, with your Super-Q on the back end. The rasp is dominating the overall sound of the exhaust and I'm embarrassed driving the car at this point. Have tried for a couple months to troubleshoot it without success. Will be contacting your support folks about the issue. Very much hoping to get this resolved now that it's prime Miata weather here in Denver.

pander

18th April 2018, 21:18

I did order an HH but after reading the posts I changed and chose the Roadster Highflow stainless steel with my street single. The HH maybe very good but it appears that it may have some annoying issues with install and rattles.

Brian Goodwin

18th April 2018, 23:52

Cool. I'll keep an eye out for the video. In the meantime, have fun with the carbon coating!

Unless you have leak at flange into muffler (it would have to be really big for rasp to escape, you could feel puff-puff on your hand), the other answer is install a catted header instead of catless header. Most folks find the SuperQ is more than enough to control the rasp to reasonable levels with catless header setup... but obviously some are more sensitive to rasp and overall exhaust sound level and are more happy with catted header (stock or RoadsterSport). My wife's PRHT used our catted header, the catless setup on my supercharged 2007 was too much for her daily use....even with SuperQ at the back.

Maurtis

20th April 2018, 10:03

I knew going into it that the Max Power header would be louder than the Street header, but I really did not know about the rasp increase too. I wish I had but my fault for not digging further. That is also one of the reasons why I want to get good sound clips since I have the new replacement HH midpipe on. None of the sound clips I heard online actually sounded like my setup IRL. It might have to do with making videos with phones :D

I got a good deal on a slightly used ceramic coated Max Power header at a time when my OEM cat was failing, but if I knew then what I know now I would have just waited and saved for a Street header. A volume increase alone I can deal with since I figured I could get the Super-Q glass packed baffles, which I did.

Going to a Street header now means not only spending more money but also losing power, that hurts my soul, LOL.

FWIW, we were discussing this topic on the Texas NC Miatas FB page and one of the members posted this video to help demonstrate the sound difference between an HH midpipe and an RS resonated midpipe:

https://youtu.be/HgeHvzivMno?t=54s

Riskinator

17th July 2018, 22:49

Okay... I recently bought the entire RoadsterSport MAX POWER MX5 COMPLETE EXHAUST COMBO...with HELMHOLTZ Midpipe. Even went for the ceramic coated header.

It had a horrible tinny sound. Discovered the mid pipe hanger was slightly contacting the exhaust pipe. Odd that it does't fit properly. Anyway, I took the hanger off and "thought" I had it solved as the worst of the sound went away.

But today I did several spirited runs and found a loud tin-raspiness-ricey sound at around 3500 rpm under load. Gawd.... I hate it.

I've been under the car adjusting everything I can think of but to no avail. Any ideas? Do I need to take off this Helmholtz and replace it??? Not what I expected with the $'s spent. Love that there is no drone but this rice-rocket sound is embarrassing.

phoboy

18th July 2018, 12:48

I had a similar raspy ricer sound when I first installed as well, but eventually it mellowed out and now sounds just fine. I think it took well over 1k miles for the midpipe to get a good build up of carbon to smooth out the sound.

I posted a video a while back after about 2k miles on the midpipe in another thread, but it was really to emphasize the drone control and not rasp. Your header is also going to be loader then mine, but I hope it helps alleviate your concerns though.

https://forum.miata.net/vb/showpost.php?p=8678437&postcount=164

notalk

28th August 2018, 20:24

FWIW, 15K mi (2 years) on ceramic street header, HH mid, RSII muffler (w/baffles in). No complaints at all, until about a month ago. Then, developed the the start-up rattle. Goes away when warm, altho can hear a little at idle at red-lights. Comes back when the car has sat a little while (2 hours). Will keep an eye on this thread. See what the long-term prospects are for V2. Have state emissions inspection next June and will want the rattle gone by then. Hoping V2 is the cure-all and GWR will replace mine under warranty.

Mr Holiday

29th August 2018, 11:52

Brian;
Since the Super Q muffler uses a packing material, will that material "wear out" over time?
Any idea what the life expectancy of the Q is?

I'm looking at doing a complete system this winter and don't need the Cat in my area.

Reason I ask is that I am thinking of old motorcycle mufflers like a Supertrap that had replaceable packing, which did wear out.

Cheers

Mr MX-5

9th November 2018, 13:46

Just reading through this thread. Do people recommend an alternative mid pipe for the NC?

JTod

9th November 2018, 15:19

I have a current generation HH mid as my first had a rattle and was replaced by Goodwin. At the time it was thought that the heat shield on the cat was the cause of the rattle. The replacement doesn't have a heat shield. It seems as though the replacement has developed a little rattle as well, as per notalk's experience it goes away after warming up. I have looked for any point of contact that could change with expansion and contraction and found none. I'll just put up with the cold rattle because the ability of the HH to kill the maddening drone is easily worth that small sacrifice.

Mr MX-5

12th November 2018, 23:10

What about the RoadsterSport mid pipe as an alternative to the HH?

KGMonteith

13th November 2018, 15:55

I have the updated HH mid pipe between a MaxPower ceramic header and a SuperQ muffler, and have also added the tailpipe baffle inserts. I don't notice any drone at all, and the car is relatively quiet when cruising but still sporty when accelerating through the gears.

Mr MX-5

20th November 2018, 09:19

Is the updated HH mid pipe less prone to rattle?

Maurtis

20th November 2018, 11:22

Is the updated HH mid pipe less prone to rattle?

I would think so since the midpipe no longer has heat shields to rattle and the HH chamber bracing was moved.

Jpnc3

19th January 2019, 18:25

Is the updated HH mid pipe less prone to rattle?

I just installed my HH mid pipe and not rattle at all (installed max power header and super q) as well.

Im facing a different issue with the system

Chicagojoe53

23rd January 2019, 16:25

What about the RoadsterSport mid pipe as an alternative to the HH?

Yes, has anyone had any similar issues with the non-HH Roadstersport Midpipe?

E39S62

23rd January 2019, 18:16

Yes, has anyone had any similar issues with the non-HH Roadstersport Midpipe?

Both the HH and non HH midpipes made contact at the catalyst with the underbody brace on my FMSC 2.5 equipped car with the GWR lowering brackets resulting in a horrible vibration. I had to use washers to space the brace down to clear it.

I had the heat shield issue on my HH and it was replaced by GWR. Dont recall vibration or noise from other parts of the HH pipe.

Frankly if you are running a catless header and/or forced induction the HH is a no brainer. Made the car drivable with the PRHT up.

Mr Holiday

27th January 2019, 00:27

I just installed my HH mid pipe and not rattle at all (installed max power header and super q) as well.

Im facing a different issue with the system

What's the issue??

Cheers

semimojo

28th January 2019, 16:27

I bought an HH midpipe and had it installed on my 2015 NC along with the Racing Beat catless header and Racing Beat muffler from my 2013 NC. There was a very ugly buzzy tinny-ricer sound on start up that was even worse when revving the engine.

Many people in this thread describe a "rattle", but mine didn't have any sound I'd describe that way. Also I'm not sure if the "rasp" that some people describe is the same as what I am calling a "tinny-ricer" sound, or if that is yet something else. Anyway, the sound is intolerable.

The install looked good. The midpipe and clamps weren't touching anything they shouldn't. The shop removed the muffler to eliminate that as a possible source of the sound, and it subdued it almost to gone. In fact, there was only the barest hint of a tinny sound, not really ricey, that you could still hear without the muffler. So it seems that the muffler may actually exacerbate the noise.

It made us wonder whether the choice of muffler might be critical. It seems like most people go with a Super Q. Has anyone else paired an HH midpipe with a non-GWR muffler, particularly the Racing Beat muffler, on a system with an RB or other catless header? What were your results?

By the way, I had the shop remove the HH and put the OEM midpipe back on. There was no way I was going to drive around with that noise. They drilled the OEM pipe and welded on a bung for the O2 sensor. It sounds fine with the RB header and muffler, but there is some drone, mainly at highway cruising speeds. That's exactly the setup I had before on my 2013, so I'm pretty used to it, but I was hoping to get rid of the drone with the HH.

KGMonteith

28th January 2019, 23:14

I have the MaxPower cat-less header, the HH mid-pipe and a SuperQ muffler, and love the tone -- no raspiness, no drone, just a deep throated roar when accelerating hard up through the gears with pops on downshifts, but relatively quiet when cruising steady state. I get compliments from my fellow Miata club members, such as "best sounding Miata in the club" of 30-40 cars. I initially tried the OEM muffler with the header and mid-pipe, but it was horrible -- sounding like the typical "fart-can" muffler with lots of rasp. The SuperQ / HH combination is the way to go for my particular preference.

https://farm5.staticflickr.com/4880/33037058568_86a07cc8ab_k.jpg

AllthingsMazda

29th January 2019, 01:20

https://farm5.staticflickr.com/4880/33037058568_86a07cc8ab_k.jpg

That's strange, I have the OEM muffler, powermax header, and roadster Sport midpipe. No drone, no rasp, sounds quiet, and tame, just maybe 10% louder than stock when I get on the gas.

semimojo

29th January 2019, 09:40

I initially tried the OEM muffler with the header and mid-pipe, but it was horrible -- sounding like the typical "fart-can" muffler with lots of rasp. The SuperQ / HH combination is the way to go for my particular preference.

Nice looking group of cars there.

Thanks for your feedback regarding the OEM muffler with HH mid. I have one and was thinking of trying it with the HH mid, but you've saved me the trouble.

That's strange, I have the OEM muffler, powermax header, and roadster Sport midpipe. No drone, no rasp, sounds quiet, and tame, just maybe 10% louder than stock when I get on the gas.

You said in your post that you have the Roadster Sport mid-pipe, and your sig says you have the 1.8 header and a 2.5SS motor. We're talking about the HH mid-pipe, RB 1.7 or GWR 1.6 header, and OEM muffler on a 2.0L engine. Very different setups, especially since you don't have the HH, so not really strange that your results are different.

semimojo

29th January 2019, 12:08

What about the RoadsterSport mid pipe as an alternative to the HH?

Yes, has anyone had any similar issues with the non-HH Roadstersport Midpipe?

I have the Max Power 1.6 catless ceramic header and RoadsterSport HighFlow midpipe and Race Single muffler on my 2013. No rattle, rasp, or tinniness. It's all LOUD goodness on the race track, but drones like crazy on the highway.

jim dreiling

29th January 2019, 12:17

I'm running the stock header, HH mid, and an original "Q" muffler. I get the tinny sound on start-up, but it's gone by the time the idle settles down to normal, from the 1800, start-up, rpm.

Maurtis

29th January 2019, 12:39

And it looks like some of the original HH midpipes had included heat shields that could rattle. The v2 design got rid of the heat shields and improved the bracing for the HH chamber.

semimojo

29th January 2019, 12:44

I'm running the stock header, HH mid, and an original "Q" muffler. I get the tinny sound on start-up, but it's gone by the time the idle settles down to normal, from the 1800, start-up, rpm.

Thanks Jim. Tinny sound on start-up that goes away when the revs drop, while still not ideal, might be tolerable. It seems reasonable that a catless header would make the tinny sound louder on start-up, so perhaps not as tolerable.

The current Super-Q may be better at suppressing the tinny sound than the original Q. I would buy either the Super-Q or the RoadsterSport II if I knew they would kill that sound. I'd prefer the lighter and slightly louder RS II if it could do the job, but even the portly Super-Q at near OEM muffler weight is lighter than my grossly overweight RB muffler (31.8 lbs).

gripLust

25th July 2019, 16:33

I'm currently going through this setup on my son's '15 - wish I found this thread a few weeks ago. That's life.

Currently the car has the MaxPower header (no cat), HH midpipe, and Super Q muffler...but it was an evolving process, and still is.

I originally ordered the MaxPower header and HH midpipe to compliment his already installed GWR Street Single. After starting the car I immediately walked in the house and ordered the Super Q; the raspiness was just too much. So bad in fact my son was embarrassed to drive it...and he's 18! :rofl:

A few days later the Super Q shows up, and that helped, but not enough. We installed the included inserts into the muffler tips, and that might have helped a little, but hard to tell. Walked back in the house and ordered the glass-pack baffles.

A side-note on the Super Q: Having the muffler supported on both sides (as opposed to the Street Single) while supporting a somewhat heavy midpipe keeps the midpipe from bouncing around.

A few days later the glass-pack baffles arrived and I went for a drive. Again, it helped a little, but not enough for our taste. Walked back inside and called GWR.

Ended up speaking with Ryan and he was great at explaining the HH. As it's been previously mentioned, the HH was designed for drone, not raspiness. The ideal midpipe would have an inline resonator and the HH, but there's simply not room.

Ryan explained the RoadsterSport Midpipe (5" high flow cat - as opposed to 4" since he races - and 18" resonator) does a great job at reducing drone, and provides a deep tone that shouldn't have any raspiness, so I placed an order and currently waiting.

9 times out of 10 the noise everyone is complaining about is because of the catless header, very rare is it actually a rattle. This is not a problem with GWR header, but simply a characteristic of catless headers. I went through this same headache with my Shelby GT500 when I added catless headers. It had such a LOUD and obnoxious raspiness that it drove me mad. The solution was ultimately to eliminate the X-pipe and have a custom H-pipe installed in its place, and add a the longest inline resonators (basically glass-packs) on each midpipe (one per side). Can't remember if it was Magnaflow, Flowmaster, or Borla...doesn't really matter. That solved the problem and the sound was beautiful. I ended up selling the car to a guy from Anchorage, so I drove from Dallas to Seattle to meet him at the airport, and the sound was never annoying along the way.

That's a long way of saying if you don't like the raspiness the solution is what Brian previously stated, which is packing material as found in the Super Q and in the 18" resonator.

Sound is subjective, so when someone says they have the same setup and they love the sound, that doesn't mean they're not hearing the same exact thing as someone that hates it. Two guys can look at the same woman and one may think she's beautiful while the other thinks she's average. :dunno:

Below are a couple videos I made during my experimenting with exhaust options on the Shelby. In the longer video you can see the resonators as the car drives over the camera.

https://www.youtube.com/watch?v=ZZ7jf38zMO4

https://www.youtube.com/watch?v=8MUkbChy9zQ

I'll report back after the GWR midpipe w/5" cat is installed.

trikwires

25th July 2019, 17:51

Funny, I have the opposite issue. I have a catless OpenFlash stainless header, stock midpipe, and a Flying Miata muffler that is thier Supercharger stainless version. It was slightly smaller that stock muffler only by a a few inches. Went with it over the "normal" muffler they offer because I was afraid if being too loud and regretting my purchase. They don't sell it anymore for some reason... maybe cause the muffler is really too quiet.
I hear it a bit when I get on the gas but it is not much otherwise. It is louder than stock and supposedly flows way better.

Not sure how comparable it is to a SuperQ, but I kinda wish I had it a tish louder. I am swapping in a 2.5L so maybe it will be louder but from what I have heard it only gets a little deeper.

Just thought I would post since it is interesting how what seems to be similar exhausts apparently are not so.

Twodoor

26th July 2019, 08:37

Just installed the full max power setup from Godwin (catless header, HH midpipe, Super Q muffler) in my garage on jack stands... Everything is lined up correctly and no rattles! I loosely installed the header to midpipe nuts, placed the front section of the midpipe on a spare jack stand supporting the cat, then installed the super Q muffler... then lined up the back half of the HH midpipe with the muffler flange and inserted into the front half. I then installed all under body cross braces to make sure nothing was hitting / rubbing. I then tightened everything up and only after everything was tight removed the jack stand under the cat. With the jack stand in place, the hanger on the midpipe was not even installed because I had the pipe high up in the tunnel. After the jack stand was removed I put on the midpipe hanger and everything is lined up perfect.

I just removed the stock baffles in the muffler tips because it was too quiet with them installed.

I am always confused by people putting on a performance exhaust system and then being shocked that it is louder than stock.

Keith

gripLust

26th July 2019, 08:47

I just removed the stock baffles in the muffler tips because it was too quiet with them installed.

I am always confused by people putting on a performance exhaust system and then being shocked that it is louder than stock.

Keith

I've read all 8 pages, and I don't recall anyone being upset about it being too loud (maybe I missed something). The issues are either there's a rattle, or it's too raspy.

Twodoor

26th July 2019, 12:15

I've read all 8 pages, and I don't recall anyone being upset about it being too loud (maybe I missed something). The issues are either there's a rattle, or it's too raspy.

I understand the rattle complaints, and it looks like the V1 with the cat that had an external heatshield was a rattle trap, and the old HH chamber support could lead to broken welds... so pleased to have the V2 of the system! I hope that anyone with a V1 system that had problems got it replaced with a V2 under warranty.

A lot of the complaints now seem to be of the "when I go WOT it is annoying" or "I am embarrassed to drive the car with this exhaust tone"

My other car is a Chevy Bolt... significantly faster than a stock Miata and absolutely silent! If your performance exhaust annoys you, go get some instant torque EV action.

Keith

gripLust

26th July 2019, 12:32

A lot of the complaints now seem to be of the "when I go WOT it is annoying" or "I am embarrassed to drive the car with this exhaust tone"

My other car is a Chevy Bolt... significantly faster than a stock Miata and absolutely silent! If your performance exhaust annoys you, go get some instant torque EV action.

Keith

Again, people are not complaining because it's loud. It would be foolish for anyone to install a race exhaust and be upset that it's loud under WOT. I would say most want it loud under WOT.

What people don't like, and like me did not expect, is the tin-can-raspy-16-year-old-with-zits-that-works-at-Taco-Bell-and-drives-a-ragged-out-Civic sound.

To be fair the sound is beautiful under moderate throttle, but crack it open and the monkeys have a party!

https://photos.smugmug.com/Cars/2018-Mazda-MX-5-Miata/i-j6p6VMT/0/099bd7cd/M/monkey-M.jpg

jim dreiling

26th July 2019, 12:42

Again, people are not complaining because it's loud. It would be foolish for anyone to install a race exhaust and be upset that it's loud under WOT. I would say most want it loud under WOT.

What people don't like, and like me did not expect, is the tin-can-raspy-16-year-old-with-zits-that-works-at-Taco-Bell-and-drives-a-ragged-out-Civic sound.

To be fair the sound is beautiful under moderate throttle, but crack it open and the monkeys have a party!

https://photos.smugmug.com/Cars/2018-Mazda-MX-5-Miata/i-j6p6VMT/0/099bd7cd/M/monkey-M.jpg

The Tinny/Fart Can sound goes away as the mid-pipe warms up/matures/ages.

gripLust

26th July 2019, 12:50

The Tinny/Fart Can sound goes away as the mid-pipe warms up/matures/ages.

I've heard about 500 - 1,000 miles for the carbon to build-up. Does it really "go away", or just reduce?

Zala

26th July 2019, 13:20

Guys lots of people that report success with sound quality are leaving the stock midpipe on mix/matched with a header (non-long tube) and/or muffler of your preference.

There are described tradeoffs if you choose an aftermarket midpipe HH or not. So... If you don't like some drone, rattle, or rasp, maybe just leave the stock midpipe on and call it a day. Sounds like you'll deal with one of the negative symptoms if you swap it.

I got some drone in my setup, but I like the sound at full throttle, so I leave it.

jim dreiling

26th July 2019, 14:57

I've heard about 500 - 1,000 miles for the carbon to build-up. Does it really "go away", or just reduce?

Reduced by about 90-95%, so to me, it's gone away, along with the drone.:wave:

gripLust

26th July 2019, 21:21

Reduced by about 90-95%, so to me, it's gone away, along with the drone.:wave:

Good to know. I was going to sell the HH for 1/2 price (basically brand new), but I'll hold on to it a little longer and see how he likes the RoadsterSport HighFlow.

It also looks like there may be room for the muffler shop to weld in a straight-thru resonator like this one if it needs a little more hush...

https://www.magnaflow.com/products/10416-performance-muffler-magnaflow-4-round-centercenter-straight-through-performance-muffler

Just need to get under the car and look at measurements once the HighFlow arrives.

Nc1l5

1st March 2020, 20:54

I'm currently going through this setup on my son's '15 - wish I found this thread a few weeks ago. That's life.

Currently the car has the MaxPower header (no cat), HH midpipe, and Super Q muffler...but it was an evolving process, and still is.

A few days later the glass-pack baffles arrived and I went for a drive. Again, it helped a little, but not enough for our taste. Walked back inside and called GWR.

I'll report back after the GWR midpipe w/5" cat is installed.

How did this work out for you? I'm trying to decide which mid pipe to go with on my car.
2.5 swap, 1.8 header, rs2 duals

tbearmiata

4th March 2020, 09:13

The Tinny/Fart Can sound goes away as the mid-pipe warms up/matures/ages.

I hope so. I've had mine on for maybe 1500 miles and my wife asks why my car farts/"backfires" all of the time.

semimojo

4th March 2020, 11:16

^--- The "Tinny/Fart Can" sound is not the same as the "backfires" that your wife refers to as car farts.

Some people report that the "Tinny/Fart Can" sound goes away under some conditions. If you're getting backfires, that's going to happen no matter what. That's mostly a function of a more open, less restricted exhaust.

semimojo

4th March 2020, 11:21

How did this work out for you? I'm trying to decide which mid pipe to go with on my car.
2.5 swap, 1.8 header, rs2 duals

gripLust removed the Helmholtz midpipe and installed the GWR high flow midpipe with 5 inch cat. On the several occasions I ran into him or his son since then, they were both happy with the high flow midpipe.

MXTRACAR

4th March 2020, 17:05

I don't recall this tinny sound ever on my HH but then again its been on for a couple of yrs (or more). The only thing I can hear is a bit of burble going down below 200 (deceleration, foot off gas or brake. That sound I wouldn't mind hearing more of but I don't think I'd be a candidate for a "popcorn tune" either. I'm pretty happy with my system now. Just don't want to deck it along side L E O.
:jump::thumbs::jump::thumbs:

indipino65

7th March 2020, 08:47

Haven't seen this thread but it speaks volumes to my situation with the tin can sound.

If I'm understanding this correctly, replacing the HH midpipe with the GWR high flow midpipe with 5 inch cat, would eliminate or reduce the tin can raspy sound. Correct? .

Brian suggested going with a catted header, but mentioned that most folks find the SuperQ as able to control the rasp to reasonable levels. While referring to Maurtis video, it doesn't seem like the SuperQ is able to, which is the predicament that I am in.

It is reassuring that as Jim Dreiling puts it that the tinny/fart can sound goes away as the mid-pipe matures or ages (1,000 to 2000 miles?) I am able to tolerate the sound (first 2 months) because it goes away, after it is warmed up.

I'm hoping it goes away. I'm waiting to hear "how happy" gripLust is with the GWR midpipe with 5 inch cat. After spending $1,700, I'm a bit reluctant to spend another $500. I wish I heard Ryan's suggestion of the RS Midpipe with 5" high flow cat and 18" resonator, a bit earlier. :dunno:

Update: Just saw the new thread and not too optimistic about cutting and welding the midpipe. Was this a fluke or one-time situation? I guess I'm going to have to wait this one out...maybe in 2 more months, it will sound better.

tbearmiata

7th March 2020, 10:42

^--- The "Tinny/Fart Can" sound is not the same as the "backfires" that your wife refers to as car farts.

Thanks for the info.

jim dreiling

8th March 2020, 14:16

Haven't seen this thread but it speaks volumes to my situation with the tin can sound.

If I'm understanding this correctly, replacing the HH midpipe with the GWR high flow midpipe with 5 inch cat, would eliminate or reduce the tin can raspy sound. Correct? .

I'm not sure I've even put 1000 - 2000 miles on mine, and the tininess is completely gone.

Rich Velardo

9th March 2020, 11:17

The only thing I can hear is a bit of burble going down below 200 MPH(deceleration, foot off gas or brake.

:thumbs: How's this version of reality?

The issue with the HH pipe on mine is only at fast idle on start up. Once the car has run for long enough to let the idle drop it's fine from then on. Even with the turbo it sounds good.

Floridaman

19th February 2021, 21:15

I have a V1 HH mid-pipe with a catted goodwin header and super Q. It was professionally installed by Treasure Coast Miata who advertises on this site frequently.

The dreaded rattle started during acceleration and low rpm's in each gear. It is driving me crazy, makes me not want to drive the car. My wife now refuses to touch it because of the rattle. I had it at the shop for 2 hrs today, they looked at everything and tried a few things, and in the end they said the mid-pipe is rattling. I am really happy that I found this tread today because it is obvious that this is an initial design issue prior to V2. In a previous post to this thread Brian Goodwin said to call his shop for resolution of these issues, warranteed for life, etc, but I got to that post too late for today, will be calling first thing Monday morning.

adibs

19th February 2021, 21:34

Hey everyone,

I have a decent quality sound clip with stock muffler and stock header. New HH midpipe ~ 1000 miles ish at recording.
I will be getting the long tube carted header from goodwin soon but here is a sound clip for people to comment on and perhaps enlighten others about how they feel about the sound.

https://youtu.be/uxJo5sstJm8

Cheers,

Alex

Spindrift

22nd February 2021, 11:19

Hey everyone,

https://youtu.be/uxJo5sstJm8

Cheers,

Alex

Thanks for the vid! Impressed with proof that just the their mid-pipe uncovers some burples and pops!

thenameiszac

22nd February 2021, 18:09

Hey everyone,

https://youtu.be/uxJo5sstJm8

Cheers,

Alex

Love the clip - made me purchase the HH MidPipe.

I just received the HH Race Muffler also so excited to see how both will sound.

adibs

27th February 2021, 13:25

Love the clip - made me purchase the HH MidPipe.

I just received the HH Race Muffler also so excited to see how both will sound.

Thanks, I will update when I get the long tube headers (catted) from Goodwin.
so a new sound clip will be on the way.

DBWard

4th August 2021, 19:56

Most modern cars have a start up routine/program/cycle that makes them much louder for the first few minutes, this helps emissions during the first few minutes, helps the cats get up to temp as quickly as possible.

killbride

6th August 2021, 08:03

So I've been struggling with this rattle/rasp for a few weeks now, ever since installing 1.6 headers to go with my HH mid and super Q. I'm finally confident in saying I was able to fix my issues with the system. I had a marked improvement in sound with the packed baffles installed, and I'd read about those that switched to the resonated mid and eliminated this noise. I figured the only way to go was find a place to put a resonator and see what happens. I really did not want to give up on my exhaust that I'd spent so much time and money on. reverting to the oem mid wasn't gonna make me happy, and the associated drone certainly wasn't either. So my goal was to find the narrowest OD resonator I could, and place it between the slip joint in the midpipe and the bend just after the cat. It needed to be as slim as possible to clear the X brace that covers the slip joint. I have resigned myself to spacing that brace down a few mm to accommodate this, turns out I don't need more than maybe 5-8mm.

I picked up a 10" long, 3.5" OD borla resonator part number (400938), which seemed like it would fit the bill. All the other resonators on the summit site were 4+ inches in diameter, so I paid the premium for this slimmer form factor. Cost me 130 after tax.

Pictures of installed resonator here (https://imgur.com/a/vwsZ6K1)
X brace removed for visibility

So the setup as it sits is 1.6 ceramic headers, modified Goodwin midpipe, super Q with packed baffles installed (and sealed around the edge with aluminum tape). In this configuration the rattle/rasp inherent to this system is almost completely gone. I'd say 95% reduction, under certain loads it's still faintly present, but nothing like it was. It's downright quiet when cruising now. With the baffles removed, some of the rasp returned, so I promptly put them back in. Cold starts are quieter with no hint of the dreaded kazoo noise. It's faintly present before the exhaust has warmed up, but after a few mins it fades and sounds perfect. I'm SO pleased with the results. I'm am no longer embarrassed by my car and no longer worried about irritating the neighbors. I've got my car back! THIS is what I was expecting to hear when I swapped the headers, not the fart can/kazoo nonsense. Will post video of before resonator + packed baffles and after. The difference is quite noticeable. I was very concerned that the tiny borla resonator would not capture enough sound as Brian says in the resonated mid description that an 18" (presumably 4 or 5 " OD) is necessary to tame the sound. Pleased to say a 10" does well enough for me, plus I get to enjoy NO drone at all!

killbride

9th August 2021, 09:56

here is the clearance between the resonator and X brace. honestly, if you are willing to space that brace down a few mm, you could probably fix a 4 inch diameter resonator (much cheaper and would only sit 1/4 in lower than whats pictured). if one is willing to eliminate the slip joint, there IS room for like a 16-18 inch length resonator between the helmholtz chamber and the bend in the pipe. I get why good win doesnt do this, I'm sure it would push the 800 dollar price tag even higher, on top of making the shipping unrealistic. but it CAN be done. you can fit a cat and resonator before the helmholtz chamber without too much fuss

scoad

13th August 2021, 09:18

That's clever, I wish I'd thought to try something like that before just switching out the midpipe for the resonated one because the HH did have a bit lower cruising volume but the resonated tamed the "90s honda" sounds that happened when I accelerated.

If they offered a "best of both worlds" setup like you built, with a small resonator and a HH chamber, I'd be super tempted to upgrade.

Can you share a pic of what you did to the baffles with the tape?

JTod

15th August 2021, 01:02

Thanks for the info killbride, I may do the same.

killbride

16th August 2021, 07:44

here (https://forum.miata.net/vb/showthread.php?t=723456) is a thread discussing sealing the packed baffle tips. credit to these guys for that idea. i used that DEI fiberglass backed silver heat tape available at most auto parts stores. works perfectly. though i did run out and used regular aluminum HVAC tape on one tip, which i cannot recommend. the adhesive melts off the tape and makes a little goopy pile on the tip which is no bueno. stick to that DEI stuff

killbride

23rd October 2021, 10:04

So I figured I'd update this thread with a bit more info now that I've lived with my modified system for a couple months and a few thousand miles of driving. I've noticed a couple of things. First, i think I found another potential source of noise in my particular system. I believe I had a very slight leak at the header to midpipe spring loaded joint. I ran that midpipe/header combo for about 2 months with the oem stud/nut/spring hardware. When I bought my used header, it came with a rusty stud stuck in the flange, which I wanted to remove. but, never got around to ordering oe replacement hardware. I figured the springs were fine, everyone else claimed to reuse them so I did too. That's when I stumbled on this (https://forum.miata.net/vb/showthread.php?t=713447) thread about replacement hardware on the cheap. Dorman part number 03123. I much prefer this hardware, as it is a bolt instead of a stud and nut. Should be easy to remove if necessary. I noticed when I put one new hardware in with and old stud/spring that the whole joint was being pulled towards the new hardware. Not really scientific I know, but it seems like the dorman stuff is putting more pressure on the header donut gasket. This is backed up by the reduced raspy rattle I'm getting. It's definitely reduced the sound a bit further. Nothing super night/day dramatic, but it's noticeable. Once the car is warm, the noise is 99% gone with the top down. Top up, it's veeeery faintly present but it's further reduced from the previous levels. Never though some bolts would make it even better but here we are :dunno: