sajadius

Hey I just straight piped my one side may I ask what u asked ur mechanic to create the dual exhaust? How did he run 2 pipes out and also what tips did you use.

JDeezyNYC

Sorry just seeing this message now. I ran the pipes right after the resonator into two, one on each side of the spare tire well. The passenger side was a tight fit with the battery well. My mechanic welded on quad tips, similar to an M5.

JDeezyNYC

hope this helps

Eurobahn BMW

Sounds great!

ucsbwsr

Title is pretty misleading as straight pipes usually means, well, straight pipes, as in no mufflers, resonators, or cats ...only piping.

What you did is essentially a muffler delete and since you still have the 2ndary cats, oem resonator, and I am assuming, primary cats in place they will offer substantial sound deadening. True straight pipes will yield a VERY different result.

I am pointing this out to avoid future confusion between straight pipes and muffler delete for newcomers who may see this thread.

That being said it looks like your fabricator did a clean job, mig welding can be sloppy and is usually done carelessly by most muffler shops. Also the oem dual IN single OUT resonator is bespoke for the 535i (compared to 135i and 335i) and IMO the main reason the 535i sounds so different compared to the smaller N54 chassis.

Evan

JDeezyNYC

yea you're right. I'm considering ditching my 2ndary cats (keeping primaries) What can I expect from this?

ucsbwsr

A little bump in sound. With the primary c-converters and oem resonator in place it will still be very quiet. If you later remove the primaries your exhaust will flow MUCH better and be even louder. The oem resonator does a really good job of keeping rasp and drone down so if it is left in place it should never to crazy loud, although exhaust preferences are pretty subjective.

Evan

JDeezyNYC

Thanks bud, I would only consider it for power increase. Right now the car sounds perfect to me. Do you think it's worth the small power increase ? (if any?)

Your wagon is sick BTW

ucsbwsr

Thanks for the kind words about the wagon.

If you want power then focus on downpipes first as they are the most restricting. The oem 335i cat-back system has been proven to flow very well and support 700whp levels so I would expect similar performance from the 535i catback. IMO the only issue with the oem system (or "performance" systems) is they sound terrible. But if you are only worried about performance catless downpipes and stock cat-back will be your best performance bang for the buck. You can try playing around with

The best of both words is a custom single 3" or 3.5" system. High flow and great sound.


Evan

shawn.ahmadi

just a question for anyone whos gone straight piped, did you notice any loss in low end torque or changes in back pressure. im currently running umnitzas quad exhaust and was looking to do a resonator delete as well or even a cat but im afraid a cat delete will throw codes and I don't wanna get those o2 sensor sims