radarcontact

Was looking at RealOEM.com and saw that the exhaust system on the 535i (my 2010 at least) go from the Downpipes to TWO long pieces of pipe with TWO individual-bank cats, then a "center muffler" (resonator?) which is shared by both banks, then off to the rear to meet TWO more mufflers. That's quite a bit!
(Maybe 335i's are the same?? I dunno)


Lots of weight I'm sure, but how much flow restriction??


I'm really kinda curious what would happen to the interior sound level if the 2nd set of cats were replaced with straight tubing and either the rear or center mufflers were deleted. Maybe just one good quality muffler at the end, nothing in between it and the motor??


For me personally, I wouldn't mind having a little more exhaust note, but I'm paranoid about ANY kind of interior drone. I like the car quiet when I'm not stepping into the gas pedal! Maybe I would want to keep my center muffler for that reason. Again, I don't know but I'm curious.


Any thoughts?


What have you done or seen/heard done to a 535i exhaust system?

rice_rocket88

There are plenty of people who have removed various pieces.. you can find some of the clips on youtube, however they will certainly not explain about drone in the inside... it certainly seems hit or miss depending on the muffler you choose and or the pieces you remove.

I removed the muffler and went to quad tips. The mufflers weigh a ton, and certainly put a little backpressure in compared to the "new" mufflers. I wasn't really concerned necessarily about performance vs the looks I was bored. The sound level increased by maybe double the stock muffler with the secondary flap opened. Although to me it was so quiet to begin with. I don't have any drones or problems.. and have thought about removing some other pieces of the exhaust, but in the end since I don't really "need" my car to be faster I haven't pursued it. Good luck!

radarcontact

Thanks for the response!

So, you removed the rearmost mufflers (at the bumper) and replaced them with nothing (just tips)?

That's interesting...again, thanks!

rice_rocket88

I cut it right around the axle.. routed and hung it.. then cut the bumper to fit dual mufflers.. it's very much like the umnitza quad tip option.

radarcontact

Nice!!

anthracite

Most people I have spoken to say that downpipes are the best mod to do and keep the 2ndary cats. If you remove the 2ndary cats then you want to add resonators somewhere or you'll get a lot of drone. I agree the stock exhaust seems like a heavy design, but I guess it keeps noise down vs having a single 3 inch pipe.

Steve K.

radarcontact

Yes, I've done the Downpipes and, yes, it makes a world of difference. Hardest mechanical work I've ever done in my life...16 hours under the car on a creeper. Ridiculously tight. V-clamps should be outlawed! Lol.

Thanks!

chea

Only a few options for bolt on exhaust options and they are all 1k plus. I already ordered a exhaust tip and 2 vibrant resonators to do a muffler delete. The dp really did make my wastegate rattle way worst.

Boost7

I did a quad setup for a 535i, kept the secondary cats since we live in Ca. Exhaust is pretty tame, roar when you mash it, no annoying rasp, no drones. The car response much better since the exhaust is opened up now. I'll post up some pics in a bit when I get to my other computer.

Boost7

Here are some pics - All Vibrant Exhaust parts