So. I live in the GREAT state of minnesota and we dont have emissions. I have a 91 318is with the M42 motor. Being that i dont have a HUGE moral delema polluting the air with my car, what would stop me from getting a 2.5 or 2.25 inch pipe custom bent from the header back running to one muffler? I understand that there would be very little backpressure... but i feel like my valve springs are capable enough to not get any float like big V8 guys. Also... i was looking underneath my car... and the pipe that i would get bent wouldn't really have many bends in it at all.... it would be fairly straight. I wanna hear everyone's input good or bad.... but back it up.
Exhaust!
- Thread starter drifty30
- Start date
A 2.5 inch exhaust on a little 4 banger could very well make the car slower. You are correct in saying that the backpressure will be reduced fairly significantly. However, you need backpressure in order to build low end torque. If you remove a significant amount of backpressure, the engine may breathe better at high rpm, but your torque may actually suffer significantly. On an engine the size of yours, I would not do this unless you have extensive modifications and need the extra flow capability. As with cams, gears, carburetors, manifolds, and most other things on cars, bigger is not always better. Instead of upping the pipe size, you might just look at a new muffler instead.
I put the Dinan exhaust and cut out the cat . We have no emissions in Hawaii either. I did keep the resonator because the muffler guy said It might be too loud . Well with the cat cutout and the Dinan exhaust its alittle loud , so I'm glad I kept the resonator . Its especially poud when going up hills and putting a load on the engine. I agree with the others to stay with the stock diameter but choose a free flow muffler .
Have you put in a chip yet ? its easy to install. It took me 1/2 hour and the results are nice. According to the dinan website , the 318is with the muffler and chip will net you 20 horsepower..
Have you put in a chip yet ? its easy to install. It took me 1/2 hour and the results are nice. According to the dinan website , the 318is with the muffler and chip will net you 20 horsepower..
The stock pipes (on my 325i anyways) are already pretty big. I could probably safely say that on e30s unless your packing some serious HP a new exhaust isnt gonna do much except change the sound. A new cat would help a bit, but IMO unless your stock exhaust is shot I dont think its really worth it to put a new one on.
i'm right by the highschool whats your name? in response to the whole "you will loose low end torque" arguement, i know i will.... but then again what low end torque is there to speak of with my motor anyways.... its only 1.8 liters. Despite all "negative" aspects i'm gonna go and do it anyways.... i'll keep you all posted. i also saw this video that changed my mind as to whether i should do it or not.
http://www.altechcorp.com/Z3/Movies/magnaflow.wmv
http://www.altechcorp.com/Z3/Movies/magnaflow.wmv
my name is in my sig.
If you're set on doing it I say go for it. If you need a muffler I would check out summit racing... sorry to sound like an AD, but for $15 you can't go wrong.
EDIT: BTW that exhaust in the clip is REALLY raspy.... I would get a glasspack palced before the muffler to reduce the rasp.
If you're set on doing it I say go for it. If you need a muffler I would check out summit racing... sorry to sound like an AD, but for $15 you can't go wrong.
EDIT: BTW that exhaust in the clip is REALLY raspy.... I would get a glasspack palced before the muffler to reduce the rasp.