"High Flow" Custom Exhaust suggestions...

[bmwman91]

Nice welding Boyracer, that is awesome!  I think my 6 year old Supersprint is dying, and i will need something else soon.  What angle is the O2 sensor bung at?  You really want it above 2 or 10 o'clock or else water from cold starts can hit the sensor and kill it real fast!

[DRtothE]

Shipping to the US might be the killer, but would you be willing to fabricate sell and ship your invention?

If not would you submit your design to fabricators here in the states to use?

My custom exhaust + exhaust manifold secondaries:

[Boyracer]

Guys, don't get too excited about few bends and pipes

I have not dynoed it yet and even when I do it, I cannot say for sure what gain (if any) is from cams and what is from exhaust system. It propably helps on high revs and hurts on low.

Also, exhaust is quite loud and I doubt you would want to use it on road for any period of time. My car is propably going to be close to Supertouring race car in comfort when I'm done while trying to keep it road legal...

[Ricer Ennemi]

I have a 2.25" pipe from cat to muffler(broke my exhaust during a 4 persons 75 mph 4 wheel jump).The exhaust shop had no 2"piping.
I bought 4\1 perf headers(dont know why!)The exit size of these headers is 1.75".I also bought a 2.25"Glass Pack to replace cat and resonator.

I achieve 16:493 1/4 mile on stock '91 318is.I just removed the headlight
(In front of the airbox),no spare tire...I will put my headers,make them shit through 1.75" pipe into my 2.25" GP and then 2.25 to good muffler.

Then I'll tell you my new 1\4 mile time(hope for 11.9).