Web www.M3Forum.net

View Full Version : Weird Engine noise issue finally discovered!


Rated///M
Thu, Jan-27-2005, 06:29:52 PM
For a long time the dealer could not find or hear what this weird engine noise I was talking about. This noise occurs when I rev the motor and while the rpms drop it makes a squealing, scratching sound. Well the dealer finally found out what it was, they said it was my Eisemann Titanium Exhaust connected to stock mids. Since the stock mids are steel and the exhaust is titanium they are heating up differently creating the sound when I let off the gas.

I was wondering if it's just my exhaust that is align wrong or is this normal for the Ti exhaust.

Here is my previous post on it

http://www.m3forum.net/m3forum/showthread.php?t=53380&highlight=weird+engine+noise

Sirius
Thu, Jan-27-2005, 06:34:14 PM
Weird, but makes sense.

M3_shin
Thu, Jan-27-2005, 06:52:37 PM
Are you sure there not just trying to connect it to your modification?? If it is the exhaust....then techinically wouldn't your warranty for that fix be voided?

Beowoulf
Thu, Jan-27-2005, 07:09:39 PM
Are the metal gaskets in place between the midpipe and muffler? If so, I'm not buying it.

ArtM3
Thu, Jan-27-2005, 07:15:14 PM
cough, cough, BS... cough...

Doctor Love
Thu, Jan-27-2005, 07:30:18 PM
If you're really curious take off your Eisenmann muffler and toss back on the stock one, if it still makes a sound, you'll know it's not a metallurgical issue ;)

gr8shandini
Thu, Jan-27-2005, 08:05:15 PM
There's no way that the exhaust is heating/cooling that much that quickly from just getting on and off the gas. It's possible that if the muffler was misaligned, the "reverse torque" from engine braking is moving the whole system around enough to do that, but that's pretty unlikely as well.

BMW F1
Thu, Jan-27-2005, 09:29:40 PM
Sounds like good detective work on behalf of BMW. Hope this now makes u rest easy.
Adam.

Thrill
Thu, Jan-27-2005, 09:36:15 PM
If you're really curious take off your Eisenmann muffler and toss back on the stock one, if it still makes a sound, you'll know it's not a metallurgical issue ;)

I would try this. The answer they gave may be correct. But sounds a little like an excuse not to spend anymore time looking to me.

DaBean
Thu, Jan-27-2005, 09:51:56 PM
Do it only if you can do it yourself.. I don't know how much an exhaust install costs, but you might be in it for a while, doing it two more times...

I'll believe it there might be room for a problem.. the metals will expand at different rates... however, I'm not fully convinced that the sounds come from that right there... and no one else with a Ti exhaust and stock midpipes has reported this...

sullyz
Thu, Jan-27-2005, 10:10:40 PM
cough, cough, BS... cough...

My thoughts exactly.

Rated///M
Fri, Jan-28-2005, 01:44:31 AM
Are you sure there not just trying to connect it to your modification?? If it is the exhaust....then techinically wouldn't your warranty for that fix be voided?


I go to a pretty cool dealership, and they won't void the warranty on it unless they know it's a mod that is causing the problem. The exhaust is just making a sound.

Rated///M
Fri, Jan-28-2005, 01:45:29 AM
If you're really curious take off your Eisenmann muffler and toss back on the stock one, if it still makes a sound, you'll know it's not a metallurgical issue ;)

Haha you know how long that would take???

Rated///M
Fri, Jan-28-2005, 01:47:45 AM
Do it only if you can do it yourself.. I don't know how much an exhaust install costs, but you might be in it for a while, doing it two more times...

I'll believe it there might be room for a problem.. the metals will expand at different rates... however, I'm not fully convinced that the sounds come from that right there... and no one else with a Ti exhaust and stock midpipes has reported this...


Well the thing is, you can barely hear it, but it is there. It could be the exhaust that was not align correctly, but the thing was that I never heard that noise till I got the exhaust installed. :nixweiss:

Beowoulf
Fri, Jan-28-2005, 03:55:07 AM
Why don't you just check to make sure it is not rubbing on the heat shield?