[RollingInDubs]

So, installed the AA EL midpipe. Drove the car for about a week and discovered the diffuser has melted. It's also starting to melt above the tips too.

The clearances are there, nothing looks different vs a stock M2 from a clearance/distance position. There is no areas of apparent contact either. I'm not sure what's causing it but I just dropped money on a new RKP diffuser to start all over again.

I'm beyond frustrated. I'm not saying it's not something on my end with the install but the directions were followed to the letter by people that have put exhausts on before and aren't rookies. This is a new problem to them too.

I'm not saying AA is to blame but I'm not exactly sure what could have been done different here. There isn't exactly a lot of leeway on moving this exhaust with the factory hanger/clearances.

Also, you can maybe make the argument that perhaps muffler placement is too close, but the melting above the tips?!? That's not a spacing issue. That's something else.

[Nicname]

First time I'm hearing this but this plus the tinny start up noises plus the 2 month wait makes me wonder if single midpipe was the way to go

[Midtown2020]

I’m getting cold feet too. I don’t want to make an upgrade only to introduce problems. Sorry to hear about your issues OP.

[CanadianComp]

Damn that sucks!

Just wondering though why AA Midpipe would be to blame if it looks like the melting is happening near stock muffler? Does installing mid pipe slightly change location, push back the muffler closer to diffuser?

Or hotter exhaust gases due to all the wiggles in the midpipe

[Driver87]

I had mine ready to ship a few months ago and canceled it when they called for delivery options. Wasn't feeling confident with the information I was reading.

I ordered the EL non res and muffler.

Went with the akra, obviously not the economic choice but I love the way it sounds and the fit was perfect. Videos don't do the audio justice.

[Nicname]

Originally Posted by Driver87

I had mine ready to ship a few months ago and canceled it when they called for delivery options. Wasn't feeling confident with the information I was reading.

I ordered the EL non res and muffler.

Went with the akra, obviously not the economic choice but I love the way it sounds and the fit was perfect. Videos don't do the audio justice.

You went with the entire evolution setup? No CEL's with the link pipe right?

[to_riffic]

possible that wherever you made the cut to mate the EL to the stock box, that it's pushing the muffler back further instead of being "neutral". I don't think that's AA's fault.

[RollingInDubs]

Originally Posted by to_riffic

possible that wherever you made the cut to mate the EL to the stock box, that it's pushing the muffler back further instead of being "neutral". I don't think that's AA's fault.

I thought of that. However, the tips are in the same position as stock. If the muffler was too far back, the tips would be out farther than they are supposed to be.

There's at least an inch gap all the way around between diffuser and muffler. See attached picture I took. You can see the distance between the muffler and the melted diffuser.

[Greg094]

Ugh, I just went out on my lunch break to look at my car and it looks like I have the exact same issue…has only been installed on the car for ~2.5 weeks. I'm really confused as to what could have caused this…

[sai_dee]

Is this the resonated or non-res version? Wonder if it only affects one or the other.

[ONLYACTIVE]

Originally Posted by RollingInDubs

So, installed the AA EL midpipe. Drove the car for about a week and discovered the diffuser has melted. It's also starting to melt above the tips too.

The clearances are there, nothing looks different vs a stock M2 from a clearance/distance position. There is no areas of apparent contact either. I'm not sure what's causing it but I just dropped money on a new RKP diffuser to start all over again.

I'm beyond frustrated. I'm not saying it's not something on my end with the install but the directions were followed to the letter by people that have put exhausts on before and aren't rookies. This is a new problem to them too.

I'm not saying AA is to blame but I'm not exactly sure what could have been done different here. There isn't exactly a lot of leeway on moving this exhaust with the factory hanger/clearances.

Also, you can maybe make the argument that perhaps muffler placement is too close, but the melting above the tips?!? That's not a spacing issue. That's something else.

Sorry to see this happening but it's the 1st time we have ever heard of this, the local guys here have no issues and have not had any other complaints. We at AA try to be as transparent as possible because if there is an issue we always try our best to resolve it. We will reach out to some of our locals here and have them come in so we can check the exhaust. In the mean time if anyone discover what may be the cause please let us know.

[NISFAN]

That's weird.

Potentially, removing the secondary cats makes the entire exhaust hotter ( rather than concentrated at the cats), maybe?

Or, the steel used has a higher coefficient of expansion than the stock mid pipes.

This in conjunction with the extra pipe length which will no doubt expand more because there's more of it.

Probably means you need to cut the exhaust a little shorter than what AA suggest to allow for additional expansion.

[BMW DIY Guy]

Just double checked mine.. single channel AA mid with resonated ABs, *cough* catless DPs *cough* with the standard exhaust.

I do NOT have this issue.

[Betaone]

It also happened , but not as bad as in your case . The exhaust expands a lot when it gets hot . In my case the installer had held the exhaust too far back to make the 4 tips stick out more . After positioning the exhaust further back it no longer touched the bumper . Unfortunately in your case you will have to buy a new bumper ( about 1.000 € ) and clean with sandpaper file the exhaust to clean it . While you're at it, paint it black. I have traveled 30,000 km after proper placement and have not had the problem anymore

Translated with www.DeepL.com/Translator (free version)

[ESB]

I'm afraid I realized that I've joined the club.

Pictures attached.

Although I noticed today, I don't know how long ago this happened. I originally got it installed in March and drove around a ton. Then in May I painted the diffuser black using the recommended products on various threads about it. At the time I didn't notice any issues (looked underneath for several days after the install and no issues then either).

Then today I got underneath again for the first time in about 5 months and noticed the damage.

I'm at a loss for why/how it took so long to happen for me when you guys noticed the damage within a couple weeks of the midpipe install.

I also don't know how big of a problem this is. I can't notice it unless I get underneath to take a look.

[AlpsRider]

There's really only one answer. Extra heat is being transferred to the muffler. Why is a can of worms.

[inTgr8r]

Originally Posted by AlpsRider

There's really only one answer. Extra heat is being transferred to the muffler. Why is a can of worms.

no, that is not the case.
changing pipes cannot increase heat.
Heat is what the engine puts out & unless the pipes were insulated, the heat to muffler should not change

This is 100% installation related.
The exhaust will lengthen by more than 1" when hot, due to metal expansion when heated.
If there is not enough gap from muffler to diffuser then the pipe will grow in length and make contact.

As mentioned in one of the posts above... since one of the pipes is longer than OE, there is more material, thus greater expansion than stock.
I would measure the stock gap before install, then add a bit to allow for increased expansion.

If the tips are not extended out far enough, I would address that separately.

[Driver87]

Short steel prices are up right now

[scarygary]

Originally Posted by inTgr8r

no, that is not the case.
changing pipes cannot increase heat.
Heat is what the engine puts out & unless the pipes were insulated, the heat to muffler should not change

This is 100% installation related.
The exhaust will lengthen by more than 1" when hot, due to metal expansion when heated.
If there is not enough gap from muffler to diffuser then the pipe will grow in length and make contact.

As mentioned in one of the posts above... since one of the pipes is longer than OE, there is more material, thus greater expansion than stock.
I would measure the stock gap before install, then add a bit to allow for increased expansion.

If the tips are not extended out far enough, I would address that separately.

Yeah you seem correct, here are some pics of mine with AA axleback

[turnsignalslol]

Originally Posted by ESB

I'm afraid I realized that I've joined the club.

Pictures attached.

Although I noticed today, I don't know how long ago this happened. I originally got it installed in March and drove around a ton. Then in May I painted the diffuser black using the recommended products on various threads about it. At the time I didn't notice any issues (looked underneath for several days after the install and no issues then either).

Then today I got underneath again for the first time in about 5 months and noticed the damage.

I'm at a loss for why/how it took so long to happen for me when you guys noticed the damage within a couple weeks of the midpipe install.

I also don't know how big of a problem this is. I can't notice it unless I get underneath to take a look.

Sorry for bring up a dead post, but I have the same issue with the AA single midpipe. I'm thinking the culprit is the less than satisfactory cuts that me and my friend made with a sawzall which may be pushing the exhaust back. The thing I'm wondering is that if the fitment wasn't perfect, wouldn't the exhaust just not be able to fit onto the bolting points? Were you able to fix this issue? I want to get a CF diffuser but don't want to risk it melting

[ESB]

Originally Posted by turnsignalslol

Sorry for bring up a dead post, but I have the same issue with the AA single midpipe. I'm thinking the culprit is the less than satisfactory cuts that me and my friend made with a sawzall which may be pushing the exhaust back. The thing I'm wondering is that if the fitment wasn't perfect, wouldn't the exhaust just not be able to fit onto the bolting points? Were you able to fix this issue? I want to get a CF diffuser but don't want to risk it melting

I hate to admit this since I love my car and don’t want to neglect it, but I never went through the effort of (1) re-adjusting the midpipe (I wasn’t the one who installed it and don’t know how) or (2) replacing the diffuser. I definitely wouldn’t replace it before re-adjusting the midpipe.

With that said, the problem hasn’t gotten any worse. It’s still sad and ugly to look at when you deliberately look for it, but it’s not easily visible.

[turnsignalslol]

Originally Posted by ESB

I hate to admit this since I love my car and don’t want to neglect it, but I never went through the effort of (1) re-adjusting the midpipe (I wasn’t the one who installed it and don’t know how) or (2) replacing the diffuser. I definitely wouldn’t replace it before re-adjusting the midpipe.

With that said, the problem hasn’t gotten any worse. It’s still sad and ugly to look at when you deliberately look for it, but it’s not easily visible.

I want to try and readjust it but I also didn’t really install it (my friend did most of the work) and the last time I tried adjusting it, I ended up bending the heat shield too far in to where it started making contact with the driveshaft ☠️

Whenever anyone sees my muffler, they always ask why it’s just smeared in black haha

Also same, there’s no way I’d buy an expensive CF diffuser without taking care of this issue first. What I’m confused about is that my muffler tips don’t even stick out that much, so I don’t know how it’s even making contact. There’s about an inch gap in between my muffler and diffuser, but that may just be because most of it already melted off