[jyeah]

Hi All,

I was wondering if an exhaust drone for the OEM BMW Performance Exhaust on a 2010 335i with Auto Transmission is normal? It was dealer installed, too.

Symptoms compared to stock exhaust (after 3000 miles):
1. >90 dB loud idling (measured with a sound meter) on cold start (even my fiance remarked, "Your car sounds weird."), it does settle down after 2 minutes and sounds a lot quieter after that
2. Audible low frequency droning sound with slight throttle going uphill
3. Audible low frequency droning sound when cruising on highway around 70 MPH when engine is at ~2K-3K RPM with slight throttle applied. The moment I let the throttle go, the sound droning goes away.

Is this normal?
Because I got it originally because people on the forum mentioned there shouldn't be any drones, I am considering of putting my stock exhaust back on and selling the performance part because the droning tone is very annoying. Not like the pleasant note I get from putting down the throttle.

[Streetluger06]

I have the PE and catless downpipes and I do not notice any drone. My car is quiet by my standards. At 2-3K like highway driving I can barely hear the exhaust unless all windows are up and the sunroof in popped up.

[idrift4wd]

there shouldn't be any drone, but the exhaust is louder. maybe your more sensitive to the noise?

i have a muffler delete...now thats some drone, but now im use to it.

[benzy89]

Do you have DPs?? Some people install resonators to turn down the "noise" of full, catless exhaust.

[jyeah]

The exhaust is definitely louder, no doubt. But the drone is really not present on the stock exhaust and I don't think I'm more sensitive because even my coworker can hear it, too.

I was just wondering whether or not, I should take it to a dealer and have them checked out. Since if it's normal, I wouldn't want to waste my time, but it doesn't feel like it is. Or anyone have the same experience?

[jyeah]

Also, everything else in the car is stock, other than the suspension upgrade and also a PPK stage 2 upgrade as well.

[Lulz_M3]

Drone is not normal but the loud start on a cold start is. When the car first starts it leaves the wastegates wide open, after about a minute it should settle down to a normal idle. I have the BMW Performance exhaust with catless downpipes, you can probably hear me in California when i start my car in the morning.

[TwinTurboXI]

I have a pair of resonators on my PE exhaust... The sound on start ups is much quieter now.

[Lulz_M3]

I have the vibrant resonators installed on my oem midpipes, really helped reduce the rasp but i dont think it made the exhaust any quieter.

[jyeah]

Okay, so the loud sound on the cold start is normal, but the droning is not.

So any ideas on what to tell the dealer on how to fix the droning? It's not like super loud, but it's audible in the cabin.

So the whole story is:

0. Stock exhaust working perfectly fine without audible droning
1. Took the performance exhaust to the dealer had it installed (a month ago)
2. Heard the drone, took it to the dealer again and they did some reshaping work on the exhaust. They said problem fixed so I got the car back but still heard the same droning sound (3 weeks ago)
3. Took it to the dealer again and this time they said it's normal because of boost increase and characteristic of performance exhaust (2 weeks ago)
4. Took it to an independent and they confirm they hear the sound, but mentioned any performance exhaust would cause the droning sound (however, this is an OEM performance exhaust that people said there's no droning)
5. Now I'm looking it to take it to another dealer

What should I tell them if they tell me the problem is normal? Or should I just bring it back to the original dealer and tell them it's not normal and they should fix it?

Thanks all.

[bboy8282]

Maybe take it to another dealer?

[Lulz_M3]

1) Try having some resonators welded in
2) Put the OEM mufflers back on
3) Live with it

Everything else is a waste of time.

[jyeah]

I guess right now I'm deciding whether or not I should just have the stock exhaust put back in and sell the performance exhaust.

Or if I should spend more time and getting the performance exhaust fixed with the dealer without welding a resonator.

[idrift4wd]

Originally Posted by jyeah

I guess right now I'm deciding whether or not I should just have the stock exhaust put back in and sell the performance exhaust.

Or if I should spend more time and getting the performance exhaust fixed with the dealer without welding a resonator.

its really hard to mess up an axle back installation. i mean i dont know what they can actually do to help with drone. cause any other mistake when installing would lead to another problem not drone. (ex welder messed up , not attached to hangers correctly)

look under your car for obvious mistakes.

[jyeah]

Yeah, I already did and it didnt seem like it was a messed up install. The only thing I did find on forums was that for some people, retightening the clamps made the droning sound go away. I just dont know if that's the case and I have an E90, not an E92.

[elim11]

I think people have different level of sensitivity to drone. That is the real culprit of the problem I think. OEM performance is one of the milder choices of exhaust (relatively speaking).

No offense, but it seems like you are more on the sensitive side and maybe the OEM performance exhaust is not a good fit for you.

Best of luck

[jyeah]

Thanks for the input.

I can see how I am sensitive to noise, I love the exhaust sound from the PE, it's just the drone can get unnerving (since at highway cruising, you don't really hear the exhaust note anymore just the droning). It's just some people mentioned that if your stock exhaust didn't have the drone, the PE doesn't either (maybe they're less sensitive) so I'm still debating over my head about this.

So any input is really welcomed.

Thanks,
John

[TwinTurboXI]

As others have mentioned, it's very difficult to mess up installing an axle back exhaust.

Not sure what "reshaping" the dealer could have done, that sounds like BS to me.

Your in LA, find a member with the performance exhaust and take a quick ride with one of them to determine if your drone is normal or not.

[jyeah]

Good point TwinTurboXI.

Does anyone in LA have the performance exhaust and wouldn't mind me taking a quick ride with you? (I know that's a lot to ask)

[bmwmike]

Make sure the exhaust is not leaking. You may be getting sound/drone from that. My Dealer cut the pipe and just used the clamps. I had to take it back and have the dealer properly seal the connections as exhaust was leaking.

[No_curebimmer]

My 'is' has same PE exhaust as yours...absolutely love it, no drone whatsoever, even after installing the catless DPs is awesome (sans the rasp...but different topic).

If you go back to the OEM exhaust, you'll soon may find yourself wanting the PE back. Had this issue with my previous '08 E92...

[Lulz_M3]

Originally Posted by No_curebimmer

My 'is' has same PE exhaust as yours...absolutely love it, no drone whatsoever, even after installing the catless DPs is awesome (sans the rasp...but different topic).

If you go back to the OEM exhaust, you'll soon may find yourself wanting the PE back. Had this issue with my previous '08 E92...

No cure, does your IS have the upgraded BMW PE or just the factory IS exhaust(black tips)? Not sure if you know, but the IS exhaust is not the same, it's about halfway in between stock and the BMW PE.