Exhaust Rattle

[bokyo1987]

I recently started to notice an annoying rattle when the engine is under load which starts at a little under 2000rpms. I decided to re-adjust my downpipes as well as bend the heatshield and they went away... or so I thought. I did the golf tee mod two days after the fix and the horrible rattle came back. So I plugged the tube back in and the rattle was greatly diminished. I can still barely hear it rattle at the same rpm range, but it's very, very faint. If it's truly the downpipes hitting the subframe/heatshield, wouldn't it keep rattling regardless of whether the flapper is open or not? I also remember an e92 owner describing a similar problem which vibrant resonators supposedly took care off... Anybody have any clue as to what's causing the rattle? TIA

[n54pete]

Also interested, I have rattle under > 1/2 throttle from 1-2k rpm, not sure what causing it, tried repositioning dps, no luck, bought another set of better figment dps, will swap when warmer

[edisapimp]

Sounds like snakes in your exhaust. Watch out because I think those kinds are poisonous.

[cheshirecat79]

Get under the car and move the exhaust by hand. It should contact whatever it's tapping.

[MRWILT]

I had a similar problem.... I really hope its your exhaust. Mine was the dreaded wastegate rattle on the turbos. Same exact description. Luckily because of the defect, turbos are covered up to 80K miles if it is determined that it is infact your wastegate. Took mine into the stealership expecting to get robbed 1.5 weeks later two brand new turbos and an invoice for $0.00. However I have no mods (yet). hope all goes well gents!

[Dackelone]

Are you sure its not the bracket on the midpipes?


#5 & #6...

[bokyo1987]

Originally Posted by cheshirecat79

Get under the car and move the exhaust by hand. It should contact whatever it's tapping.

I actually tried that a couple of times. It took quite a bit of force to move them, but they weren't hitting anything. Kinda wish it did just so I can pinpont the source though...

Originally Posted by MRWILT

I really hope its your exhaust.

Me too, man! I don't really hear it when decelerating. Nor do I hear anything after giving it a quick rev with the vacuum canisters plugged in. I'll give it another check though!

Originally Posted by Dackelone

Are you sure its not the bracket on the midpipes?

Hey, Dackelone! I was really paranoid about that the first time I re-adjusted the downpipes, so re-tightened them. Tight enough to get little dimples on the midpipes lol. I might just end up taking the whole bracket off and see it does anything.

Thanks for all the info, folks! Hopefully I can figure this out sometime soon... It's really starting to bug me

[edisapimp]

Does it do it only when it's warm or it does it all the time?

[bokyo1987]

Originally Posted by edisapimp

Does it do it only when it's warm or it does it all the time?

It's been getting warmer here lately and I just started to notice it lol. Can't replicate it while in park or neutral either. The odd thing is that it seems to only happen around 2000rpms under load. Sometimes I downshift while cruising and get nothing

[edisapimp]

If you can get a sound clip it would help with the diagnosis. I know that would be difficult because you have to be driving to duplicate it. But consider that you have tampered with the exhaust in a lot of different ways, and you have parts from another car (mids) on yours. Empirically I would say that some part of the exhaust is what is doing the rattling. It could easily be a gasket that's only stressed when on boost or under load, or something that expands when the car is warm that you can't see when you try to look while it's cold. Could be an exhaust hanger or bracket, could be as simple as a loose nut washer or bolt. What I find interesting is that you said the noise got worse when you did the golf tee mod, which means more noise made your vibration worse. That's a good clue as to the problem in my opinion.

Start from one end and work your way to the other, you'll find it.

[bxsinster]

mine had a rattle under load and i needed a new motor

[Swadeness]

Take a close look at number 6 in the pic from @Dackelone Sometimes the bolt will bottom out and tighten but it won't actually tighten fully against the mid pipe. With a decent bit of force that bracket can move and spin. Its quite deceiving because everything looks fine just looking at it and giving the exhaust a good shake. Mine sounded very similar to what you guys are describing and I thought for sure I had a waste gate issue. I ended up finding it by looking under the car as I played with the throttle and sure enough I could see it rattle. I ended up having to cut down a washer to fit inside the bracket to act as a shim. Good luck!

[bokyo1987]

Thanks for all the advise, folks! Will be getting underneath the 1 again soon to try and pinpoint the source this coming weekend.

[edisapimp]

keep us updated

[M3Dreams]

Originally Posted by bokyo1987

Thanks for all the advise, folks! Will be getting underneath the 1 again soon to try and pinpoint the source this coming weekend.

Did you find the source of this issue. I am experiencing a similar rattle only under load, and it started happening right after having n55 mids installed by an exhaust shop. Is there an easy way to tighten this bracket. I believe the bolt to tighten it is on the top side and not easily accessible. Is there a special tool for tightening this bolt?

TIA

[bokyo1987]

Sorry, man. I couldn't pinpoint the cause so I ended up re-clocking the DPs, bending the heat shield a bit, and re-tightening the t-bolt to the point of denting them a little. The rattling disappeared after all that, but I'm not sure which part actually caused it.