I searched and just found to old and poor info about this ...

My car came with 3 pipings custom made but they are beat... so im making another IC pipings... But i dont know if i need then 3" or 2.5"... im currently building a 2.4 engine with a 6266 turbo kit... so guys what you think is better ??

I know more ppl want to know this too so the guys that know what they are talking tell us this..!

 

3" will have no benefit unless you're making about 1k+ HP, it will add lag and reduce overall intake velocity. But if you already have the couplers and clamps to fit 3", it would save a little $.

 

it will add lag ??

1000 hp ?

i see some 600 hp cars use then but i need to know whats better

 

If memory serves correct, I recall a comparison test conducted by David Buschur that revealed no advantage of 3" IC plumbing over 2.5" around the 700whp level.

 

2.5".

3" Won't add "lag" per say but midrange power will suffer by a few horsepower. Probably a 5-10hp loss.

 

2.5" is perfect.

 

3" pipes take more time to fill with air=lag vs. 2.5". If bigger pipes don't add lag, I would love to know the reason cars aren't using 4-5" I/C pipes. The test David Buschur did was comparing a 3" vs. 3.5 exhaust and said no benefit in power was made until 700whp + being louder.

 

so 2.5 is the perfect size... !!??

 

^^ What he said!