M42 Engine/Exhaust Raspy when temp warm?

[spud814]

Hey guys,

I've been trying to fix my 318is raspy sounding exhaust. It's normally raspy except for when it's early morning and temp is like 50-52 degrees F or lower. Anything over 55 degrees the exhaust sounds very raspy, also after it's warmed up fully it's raspy again. Does anyone know whats wrong, i dont like the sound b/c it sounds like my car will blow up. :) Any advice anyone? Could it be some sensor related to temp is broken?

Thanks
-gil

[clutterbucker]

What kind of exhaust is it? I had a resonated Stromung single tip exhaust on my old E36 M42 and it was deep (four a 4banger) but a little raspy just because thats the way the motor is. Are you sure it's not the motor making that noise....because it's not a particularly nice sounding motor.

[spud814]

Well it's really hard to detect the sound, it sounds like the engine to the cat area. I had a muffler shop take a look at it, and he made a few reinforcements and took out the resonator that was rattling, but this noise is still there. I know how this motor sounds liek b/c my gf has a m42 also with low milege and hers sounds not a bit raspy at all. Again, it's not the muffler it's around the engine to cat area, more towards the front of the car.

[sparticus]

I had the same problem once and had the exhaust replaced at MIDAS but still had problems with the noise. Then I took it to a REAL muffler performance shop and it turned out it was the Cat that was bad. Had it replaced and it's been sounding fine since. How many miles on the car and when was the Cat last replaced??

[spud814]

The cat has been replaced, it sounded worse before. The muffler shop i've brought too is really knowledgeable and have tons of experience. Any other advice, could it be my engine? Does anything cause an engine to sound raspy?