Best exhaust for hp gain/not too loud?

Originally Posted by iwannagofast

get ebay headers for 150 bucks and keep thestock exhaust on... youll get more power than just putting on a cat back.... it wont be loud at all until your at WOT

can't find headers for M56 engine . If you or anyone in here has an idea or know any performance headers that will do for M56, please let me know.

wait till i get my car back from the shop, i'm gonna install some ebay headers i got a few weeks ago if you can wait till i do the install (few days) i might have got the wrong one and you can get mine for cheap cause i'll be buying another i'm almost 100% sure headers will work the exhaust is the same you just have a lower emissions motor has nothing to do with the exhaust manifold. just find out what the stock exhaust manifold part number is and see which set you need. i'll keep ya posted on my headers

Originally Posted by xixixi

exactly just like on our cars have a valve in the exhaust that is closed during idle and up to a certain point only to reduce exhaust noise in the cabin. does nothing for performance lol

lol except you're wrong, go pick up a physics book. I'm not talking about exhaust valves, I'm talking about the diameter of the pipe with respect to pressure and velocity. I believe the z06 has this feature too.

Originally Posted by fibonacci00782

lol except you're wrong, go pick up a physics book. I'm not talking about exhaust valves, I'm talking about the diameter of the pipe with respect to pressure and velocity. I believe the z06 has this feature too.

Are you sure it's not ferrari?

Flow = top end power. Back pressure = low end toqrue... usually. You want to get the best of both worlds. Also like someone mentioned the best way to get gains from exhaust is to make sure it is tuned to the rpm band that the engine uses the best.

M56 motors arent super performers anyway. If u want any noticable power get cams and a tune. Or a supercharger : ). Then get an exhaust.

I heard that even the air boxes/intakes on our BMWs are engineered so well that aftermarket intakes dont make a difference either. GO BMW

Originally Posted by IrocThe325i

Flow = top end power. Back pressure = low end toqrue... usually. You want to get the best of both worlds. Also like someone mentioned the best way to get gains from exhaust is to make sure it is tuned to the rpm band that the engine uses the best.

M56 motors arent super performers anyway. If u want any noticable power get cams and a tune. Or a supercharger : ). Then get an exhaust.

I heard that even the air boxes/intakes on our BMWs are engineered so well that aftermarket intakes dont make a difference either. GO BMW

You are an flipping ****, and I'd appreciate it if you didn't post in this thread again.

Originally Posted by IrocThe325i

Flow = top end power. Back pressure = low end toqrue... usually.

Explain to me how backpressure helps low end torque?

If you were to say that smaller exhaust pipes create more low end torque but also result in less power at high rpms due to increased backpressure, I would buy that.

Originally Posted by hoveringuy

Explain to me how backpressure helps low end torque?

If you were to say that smaller exhaust pipes create more low end torque but also result in less power at high rpms due to increased backpressure, I would buy that.

Listen to this man. He is very smart.

Originally Posted by hoveringuy

Explain to me how backpressure helps low end torque?

If you were to say that smaller exhaust pipes create more low end torque but also result in less power at high rpms due to increased backpressure, I would buy that.

Originally Posted by Iceman00

You are an flipping ****, and I'd appreciate it if you didn't post in this thread again.

WHY IM JUST AGREEING WITH YOU!?... i think.

"If you were to say that smaller exhaust pipes create more low end torque but also result in less power at high rpms due to increased backpressure, I would buy that."

Yeh of course. I should have specified why the backpressure was being caused. If theres a potato in your tailpipe i dont think ull be making more toqure

Originally Posted by IrocThe325i

Flow = top end power. Back pressure = low end toqrue... usually. You want to get the best of both worlds. Also like someone mentioned the best way to get gains from exhaust is to make sure it is tuned to the rpm band that the engine uses the best.

M56 motors arent super performers anyway. If u want any noticable power get cams and a tune. Or a supercharger : ). Then get an exhaust.

I heard that even the air boxes/intakes on our BMWs are engineered so well that aftermarket intakes dont make a difference either. GO BMW

Completely false, read the link I posted, with analysis and dynos.


Backpressure is never good.

i shall read : )
And i was wondering if u knew the best length from headers to put the y-pipe... I think im going to make a full custom cat-back but i want to do it with these concepts that u've brought up.

2" from headers to y-pipe into single 3" with two resonators and a muffler (not sure what kinda yet)...


Nevermind you said closests to the collectors.... ok.

Originally Posted by IrocThe325i

i shall read : )
And i was wondering if u knew the best length from headers to put the y-pipe... I think im going to make a full custom cat-back but i want to do it with these concepts that u've brought up.

2" from headers to y-pipe into single 3" with two resonators and a muffler (not sure what kinda yet)...


Nevermind you said closests to the collectors.... ok.

Yes, unless you have the resources to test for me the optimal distance from the headers

Originally Posted by xixixi

wait till i get my car back from the shop, i'm gonna install some ebay headers i got a few weeks ago if you can wait till i do the install (few days) i might have got the wrong one and you can get mine for cheap cause i'll be buying another i'm almost 100% sure headers will work the exhaust is the same you just have a lower emissions motor has nothing to do with the exhaust manifold. just find out what the stock exhaust manifold part number is and see which set you need. i'll keep ya posted on my headers

hey that would be awesome man, i don't know if anyone has ever done that with an M56, but if you happen to be that guy, i'd love to know how it worked. Good luck keep us posted

lol no i drive a 330xi with a m54 you need to check the stock part number for your exhaust manifold to see what if anything will work. you could even call bmw

I have Headers and the Magnaflow "catback" and i actually felt something after the i put on the Magnaflow.....i can't say how much but something but this setup is sorta loud.