Intercooler piping diameter??

[crzycav86]

What's the best size for intercooler piping on the ka?

I'm using a z31 turbo up to 9 psi and a fmic. Logic tells me to have a larger hotpipe and a smaller coldpipe if I want uniform air velocity, but what's the science behind intercooler piping? What size do the major brands use?

Discuss..

[gabossie]

Anywhere between 2-2.5" is pretty standard. 2" is pretty small, but you get into larger pipes (3") and spool time increases.

[:: orion ::]

Z31 exit is 2"...

I've seen people reccomend 1/4" bigger than turbo exit for the hot pipe, and another 1/4" bigger for the cold pipe..

So for you: 2.25" hot pipe, 2.5" cold pipe, then a 2.5" --> 2.75" coupler for the TB. Or bump the cold pipe up to 2.75" for the last foot, if you can find 2.75" piping.

- Brian

[crzycav86]

Z31 exit is 2"...

I've seen people reccomend 1/4" bigger than turbo exit for the hot pipe, and another 1/4" bigger for the cold pipe..

So for you: 2.25" hot pipe, 2.5" cold pipe, then a 2.5" --> 2.75" coupler for the TB. Or bump the cold pipe up to 2.75" for the last foot, if you can find 2.75" piping.

- Brian

So why do you want the cold pipe to be bigger than the hot pipe? Won't the air already be traveling slower after it passes through the intercooler and becomes more dense? why make it travel even slower?

P.S You mentioned the same thing in FA when I did a search 2 minutes ago.

[:: orion ::]

Hehehe...

As the air cools, it expands...so it can maintain the same velocity in a larger pipe.

(Plus, bigger IC piping aids in off-boost response...)

- Brian

[nizmo240sx_22]

I'm not a physics major, but I think that defies thermal expansion.

[gabossie]

That's what I was thinking. Cold air is MORE dense than hot air.

[:: orion ::]

Hehehe...I forgot the ...oops.

Let's try this again:

As the air cools, it expands...so it can maintain the same velocity in a larger pipe.

But the real reason is...bigger IC piping aids in off-boost response.

(Sorry, the sarcasm was lacking in my original post)

- Brian

[Redline240]

So if i wanted to use a 3" cold pipe then i should probaly use a 2.75" hot pipe...now i'm pretty sure the outlet on a T3/T04E 50trim isn't 2.5", probaly 2.25" so is there any reason i shouldn't go from 2.25"-2.75" or even 2.25-3 and have both hot and cold pipe the same size?

Redline

[andrave]

crazycav, I'm in houston, do you have IM?

[crzycav86]

Thanks for the help.

crazycav, I'm in houston, do you have IM?

yeah... crzycav24

It's in my profile.