twisted 45 Report post Posted October 21, 2009 Hey all. Sometimes my exhaust is a lot louder than other times on my 540. My Legacy has a butterfly valve arrangement in the rear can that activates at certain revs, giving it a deeper sound; and am thinking that my 540 must have something similar that must be playing up? The 540 has no cats from factory (two small bmw branded mufflers where cats would be) and has had the center muffler replaced with resonators. Normally it sounds quite muted, but other times it has a real V8 bark. anyone have any ideas? Quote Share this post Link to post Share on other sites
kiwi535 538 Report post Posted October 21, 2009 Hey all. Sometimes my exhaust is a lot louder than other times on my 540. My Legacy has a butterfly valve arrangement in the rear can that activates at certain revs, giving it a deeper sound; and am thinking that my 540 must have something similar that must be playing up? The 540 has no cats from factory (two small bmw branded mufflers where cats would be) and has had the center muffler replaced with resonators. Normally it sounds quite muted, but other times it has a real V8 bark. anyone have any ideas? not that i am aware.....prolly related to throttle position and surrounding environs..... Quote Share this post Link to post Share on other sites
twisted 45 Report post Posted October 22, 2009 (edited) not that i am aware.....prolly related to throttle position and surrounding environs..... Nope, Definitely not. My Job is testing software, and i have applied the same kind of analysis to this and there is definitely an issue here that is random in nature. My first thought was clogged cats, clogging/unclogging but then i crawled under and no cats! Only pattern that seems to be prevalent is that the car will be well warm when it starts doing it. I'm confused tbh! Edited October 22, 2009 by twisted Quote Share this post Link to post Share on other sites
BM WORLD 1270 Report post Posted October 22, 2009 maybe some of the baffels are rusty and moving around etc . Quote Share this post Link to post Share on other sites
twisted 45 Report post Posted October 22, 2009 maybe some of the baffels are rusty and moving around etc . Could be just the excuse i need to do the whole exhaust huh? Quote Share this post Link to post Share on other sites
Yuen 16 Report post Posted October 25, 2009 The exhaust flap on the E36 328 can be seen by crawling under the exhaust - you'll see a hose leading to the actuator near the exhaust tips. Would think an E34 would have a similar system if it had one. Quote Share this post Link to post Share on other sites
SiK-E34 0 Report post Posted November 12, 2009 The exhaust flap on the E36 328 can be seen by crawling under the exhaust - you'll see a hose leading to the actuator near the exhaust tips. Would think an E34 would have a similar system if it had one. I used to work in a BMW garage back in aust, i seen alot of e36 beemas with this feature, mainly on the twin tip exit mufflers, the actuators opened when car was warm and at higher revs, its possibly a back pressure feature. I could be wrong but please dont hesitate to correct me. Quote Share this post Link to post Share on other sites
