Intercooler piping size
 

Hey guys, I've been looking at intercooler kits on the market but i don't know if I should run 2" or 2.5"!

I'll be running a T25 turbo (2.5" inlet, 2" outlet) and I don't want too much restriction but I don't know if any problems arise from running piping that's too big! Any quick advice? :D

Thanks!

edit: how does 2" pipping from turbo to ic then 2.5" from ic to engine sound?

That's pretty much what I'm running. Works just fine for 400hp.

Most of the engineering/science behind it is you want the speed of the air to stay below Mach 0.4. Temp has the biggest influence on the speed of sound (humidity does too not but a huge factor).

Generally you can get away with running smaller hotside vs coldside for this reason. (speed of sound is slower at colder temps)

With that in mind... for your power goals 2.0" all the way would probably be fine.

I run 2.25 hotside and 2.5 coldside. I think the FM kit does 2.0 hot and 2.5 cold...so that would be fine for your setup. Running 2.5 coldside is nice because the TB uses 2.5" coupler for it.

Thanks! My turbo kit its well on its way thanks to many of the users on this forum

Me too. 2" hot side, 2.5" cold side. 2" hot side is nice because it's slightly easier to route through tight areas. I'm running power steering and A/C. I believe there is less pressure loss in the pipe itself as well. It may be minimal anyway.

2.5" cold side works well also because my intercooler has a 2.5" cold side outlet. This combination nets me about 1 psi, maybe a hair less, total pressure loss.

I use a 2.25in kit with a reducer on the tb, and the compressor, to go up/down sizes.

I forget how I measured it but I too see 1psi max of pressure loss. I do also have a begi #3 IC which is fairly small.

I also went with 2.25" all the way with reducers on the TB and compressor. So far I like it.