ic piping size
 

ok i thought picking up some 2.5" piping for my d16y7 with a small t3 was a good idea.... until some guys said that 2" would be better with the smaller turbo and stock motor... is this true? should i have opted for the 2" instead of the bigger 2.5?

Re: ic piping size
 

mine is 2.75" :-\

Re: ic piping size
 

think air flow. bigger pipes will have more flow capacity(volume). smaller pipes will pressurize quicker reducing lag because of less volume. you should *try to have the turbo and pipes matched to how much your head will be able to flow.

anywhere from 2 - 2.5" is good. if you're going big horsepower like weir^^ go like 3" or so

Re: ic piping size
 

Small T3 on a D16, your friend is right. 2" is better. Make sure it's mandrell bent though.

Re: ic piping size
 

i got 2" from turbo to fmic then 2.5" to the throttle body

Re: ic piping size
 

2" is the way to go

look at the area of these pipes
A of a 2" circle is 3.14*1^2 = 3.14
A of a 2.5" circle is 3.14*1.25^2 = 4.90 (thats a lot more area)
A of a 3" circle is 3.14*1.5^2 = 7.06 (thats huge by comparison)

i wouldn't use anything over 2.25" unless i was shooting for 350+ whp.

Re: ic piping size
 

And 2" and 2.25" is cheaper. 2.25 for me.

Re: ic piping size
 

Imo any tubing larger than the outlet of your compressor will hurt charge velocity and increase lag.

Re: ic piping size
 

hmm, i have a t3 60/63 and 2.5" piping all the way around and i hit 10psi at 4000... not real bad i think

Re: ic piping size
 

my personal rule is that i match pipe from the turbo to the cooler to the size of the turbo outlet.

and i match the pipe from the cooler to the TB to the size of the TB

Re: ic piping size
 

I did that on my first IC setup. I had 2" from turbo to DSM SideMount and then a 2" to 2-1/2" reducer right after the IC to go to the throttle body, which is 2-1/2". Worked good.

I added a CCA FMIC over the winter and changed all my pipes to 2-1/2", since my TB is 2-1/2" & my IC inlet & outlet are also 2-1/2"... So I have a 2" to 2-1/2" reducer right off the turbo and 2-1/2" piping throughout... I'm still undecided as to whether or not that was the right decision.

Re: ic piping size
 

smaller 2" piping is great for spoolin it up, but i prefer a little lag and better top end.

dyno proven 2" to 2.5" conversion on Alec's ZC was something like 14whp. I think the before dyno was 185whp and the after dyno was 198whp.

Re: ic piping size
 

I just did the same size as my cooler. 2.5". But my compressor outlet is 2.25". I get a bit of lag, but I rather a bit more top-end.