# Intercooler piping size



## Mervic (May 1, 2002)

What will be the ideal pipe size for turbo piping with less than 10psi of boost? Is there a general formula to get the right diameter of pipe for a given boost pressure? I am thinking of getting 2" diameter size since it is low boost application.


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## 1 WICKED SE-R (Apr 13, 2003)

just get 2 1/2" and you'll be fine
you can never be too big, but you can be too small

being a little on the piping is not gonna hurt anything


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## SE-RtinMI (Nov 3, 2002)

Mervic said:


> What will be the ideal pipe size for turbo piping with less than 10psi of boost? Is there a general formula to get the right diameter of pipe for a given boost pressure? I am thinking of getting 2" diameter size since it is low boost application.


2" is more than sufficient for a T25 or T28. If your going to run more boost than 10psi it would be a good idea to run 2" on the hot side and 2 1/2 on the cold side.


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## lshadoff (Nov 26, 2002)

You've got to balance the ability of the piping to carry the compressed air to the intake system (small diameter=increased pressure drop) against the volume of the piping between the compressor and the intake (large volume=increased lag).

For low boost, 2" piping between the compressor and the intake should be large enough to have an acceptable pressure drop (maybe 2-3psi) with low lag.

Lew


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## javierb14 (Jul 9, 2002)

2.0 in. from the comp to the IC and 2.5 in. from the IC to TB works well. we have "transitioned" to 2.5 in from the comp outlets on T25/T28's and T04E's, and there isnt much more lag....its hardly even noticeable. going with 2.0 in. will support 10psi power levels on a smaller turbo just fine. :cheers: personally, i like to match up the diameter of the piping with the IC inlet/outlets, TB size, and compressor outlet.


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## Rodrigo (Mar 26, 2003)

javierb14 said:


> 2.0 in. from the comp to the IC and 2.5 in. from the IC to TB works well. we have "transitioned" to 2.5 in from the comp outlets on T25/T28's and T04E's, and there isnt much more lag....its hardly even noticeable. going with 2.0 in. will support 10psi power levels on a smaller turbo just fine. :cheers: personally, i like to match up the diameter of the piping with the IC inlet/outlets, TB size, and compressor outlet.


what about if you go 2.5 all the way? will it affect anything


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## NotAnotherHonda (Aug 7, 2003)

i have 2" piping on my 1.6 turbo, and the lag isnt even there it seems like...currntly, i have a t25 at 7 psi, but ill see how the pipings is after i turn up the boost a little


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## Chillboy (Oct 8, 2003)

Is there a formula for this? I'm looking at getting mine replaced too, for cosmetic reasons only. I believe it's 2.5". Would that be best suited for a T3/04E GTR based turbo on a 2.5L at 17psi?


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## NotAnotherHonda (Aug 7, 2003)

Chillboy said:


> Is there a formula for this? I'm looking at getting mine replaced too, for cosmetic reasons only. I believe it's 2.5". Would that be best suited for a T3/04E GTR based turbo on a 2.5L at 17psi?



just keep 2.5"...how was it working for you before? how was lag? how was the power? did you always have it at 17psi?


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## dave_f (Dec 11, 2002)

I am running 2" hot side and 2.5" cold side. I think 2" all around would be also be fine. 
-dave


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## James (Apr 29, 2002)

me too (2 hot 2.5 cold)! I don't think it matters because you've got the intercooler in between... I just always assumed you would have the least pressure drop this way.


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## Chillboy (Oct 8, 2003)

NotAnotherHonda said:


> just keep 2.5"...how was it working for you before? how was lag? how was the power? did you always have it at 17psi?


I run 11 most of the time, but I can run 17 with pump gas. Comes on at 3K and full boost around 3600, I just thought I'd ask cuz I'm not sure if we're sandblasting and rewelding what's in there or redoing it all and it seemed like a good time to hijack. Sorry carry on...


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## OPIUM (Aug 18, 2002)

2.25 all the way around on the RB (stock boost)


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## Rodrigo (Mar 26, 2003)

OPIUM said:


> 2.25 all the way around on the RB (stock boost)


I am just gonna go 2.5 all around so that later on in the future my :dumbass: ass dont say dam i should have goten 2.5 from the get go.


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## dave_f (Dec 11, 2002)

2.5" will be fine, the only drawback is that it is a little harder to route 2.5" pipe vs. 2". you might have to do a little more trimming here and there to get it to snake around just right.
-dave



Rodrigo said:


> I am just gonna go 2.5 all around so that later on in the future my :dumbass: ass dont say dam i should have goten 2.5 from the get go.


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## Rodrigo (Mar 26, 2003)

dave_f said:


> 2.5" will be fine, the only drawback is that it is a little harder to route 2.5" pipe vs. 2". you might have to do a little more trimming here and there to get it to snake around just right.
> -dave


my main concern since i am doing my own intercooler piping is that the piping that goes from the intercooler to the turbo and intercooler to throtle body goes under the car and i dont waNT it to be too big to the point that the clerance is minimal.
Does anyone know the piping size of the hotshot intercooler kit?


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