I have a bar and plate style ic. Core measurements are 24x12x3.5 end tanks have 2.5" openings, compressor outlet is 2.5". Question being, will it make a difference if I were to open up the IC to 3" openings? Better flow maybe? Any better IAT's? Or just leave as is and step up after intercooler to TB, thanks.

 

I would step up after ic, I doubt you would see much gain in return for your time.

 

it would help, not sure how much.
i had 3" in and out on mine, i changed the out to 4" and flipped one endcap so we have top entrance, bottom exit so it uses more of the core.
my turbo outlet is 3" and throttle body was 4" so it made sense.

 

Did you gain anything that you could tell after going to the 4" exit?

For that matter, has anyone gone from 2.5 to 3" intercooler and seen the an appreciable gain, not changing anything else?

Going larger on the exit side does make sense. I have access to equipment to install the larger pipe, just want the effort to be worth while, thanks for the input! Anyone else???

 

never ran it any other way so i dont know.

 

Why don't you setup a temporary pressure gauge at the turbo outlet at just upstream of the throttle body to measure your pressure drop through the 2½" piping and interncooler. If you don't have much more than 2-3 psi drop then don't mess with it.