Im getting straight pipes after the cats on my z, but i have the option of 2.5 and 3" straight pipe. Whats the difference in the two?


Want a very aggressive tone,very loud attention grabbing, smooth and not crackly



Thanks i really appreciate it

 

If its an NA car 2.5in dia would probably be better.

 

Thanks!

Why is it that a 2.5 sounds better?

 

Sound depends on more than just diameter. I was speaking strictly on 2.5 being better from a performance standpoint.

 

Phenom um Idk if that's the best answer. Not going to say wrong but lot of grey. I'm actually contemplating a 3.5" single from my PPE headers back.

 

After the merge on the y pipe pretty much everything is for sound..it's been proven to have a 2.25-2.5 inch merge into a 3" collector perform best at the y then personal preference from there back. I prefer the gurgle the 3" exhaust systems make

 

Maybe I'm misinterpreting the layout of OPs exhaust plans. I read it as everything after the cats is coming out (so factory Y, mid pipe, and muffler is gone) and OP is running new pipes from there on each side like a true dual setup. OP can you clarify?

If its like I described and its a true dual layout, I maintain that 2.5 is better. if its a Y pipe into a single pipe then at least 3" would be ideal.

 

Diminishing returns if you go too big and exhaust velocity decreases as well. Since he's describing an OEM system system with factory cats I would assume he is keeping the Y pipe setup. 3" single is all he would ever need. If this was a dual conversation, 2.25" would be fine with nothing over 2.5" max. Keep in mind, even the 'upgraded' Nismo exhaust for these cars is a 2.5" single and that exhaust doesn't make much less power than proper aftermarket exhausts on bolton cars.