Intercooler Piping Size

[_8OO5TED_]

I have purchased a GT30R to fit to my RB25DET with all the associated and upgraded fuel/ecu/cooling neccessities but standard plenum.

Will I see any worth in going for 3" cooler piping as opposed to 2.5"? I have the option available to do, what do you guys think?

[pavel]

If you got standard plenum and throttle body I don’t see why you would need 3" cooler piping, as they are 2.5" items. Probably going to create more lag if you do decided to get 3" piping... more room for air to fill.

[mad082]

3" will create more lag, and if you are still using any of the stock 2.5" piping, not really flow any more air.

[_8OO5TED_]

if i was to do it, it would be a complete replacement of all piping for 3"stainless steel all round.

[pavel]

Your throttle body is 2.5", whats the point of having 3" cooler piping if the same amount of air will be going to your intake plenum regardless of 3" piping? all you'll get is more lag if you go with 3", just leave it 2.5" unless you want to upgrade your plenum & throttle body.

[`nigno]

Your throttle body is 2.5", whats the point of having 3" cooler piping if the same amount of air will be going to your intake plenum regardless of 3" piping? all you'll get is more lag if you go with 3", just leave it 2.5" unless you want to upgrade your plenum & throttle body.

Exactly right the volume of air required to fill 1 inch more space at your designated boost level = the increased lag time.

Get 2.5inch piping to your standard TB + Plenum, and maybe 3 inch on turbo side if you have a 3inch inlet on your turbo... I dislike reducers so thats just personal preference. Also depends on your cooler inlet/outlet size too.

[_8OO5TED_]

Get 2.5inch piping to your standard TB + Plenum, and maybe 3 inch on turbo side if you have a 3inch inlet on your turbo...

i like that idea, thanks all.

[2BNVS]

yep with stock plenum i just ran 2.5" piping, made things heaps easier plus was running less power...with the custom plenum w 80mm TB i run 3 inch on the plenum side but still 2.5 on turbo side. got hardly any lag considering the power

ben...