Best Size Intercooler Piping?

I am running an sr20det with about 300hp and i need to know what is the best size IC piping to go with, is 2.5" a little big for quick spool?

ive heard of using 2.5" for the turbo to inlet pipe and 3" for the outlet to intake manifold pipe

2.5-3" for the cold size is good as far as the hot size the rule of thumb is usually you want piping that is about 1/2" larger then the outlet size of the compressor housing

does anyone with an sr20det or similar swap know how many bends and what kind i would need for a front mount IC setup (ie how many 90 degress did you use or 45 or 180s etc) as well as possibly pictures of IC piping set ups?

A good rule of thumb is to match the size of your throttle body.. I really don't see any point in running 3" piping when your throttle body is only 2.5"(actually 2.36" or 60mm).. Another point is that you will lose air velocity when using a larger piping due to greater volume, thus a pressure drop.. Great for keeping intake temps down, bad for boost response. Though again this 3" piping is pointless if you have a 2.5" restriction .. i.e. throttle body.

velocity is more important in a n/a car, turbos pressurize the intake so it forces air in, thus negateing velocity. you can dilute the press. by going to big, but i would tend to agree with bart on this one.

I've heard all types of rumors on IC piping.. One of the most infamous being 'velocity stacking'.. Frankly I wouldn't believe any of it even if there were 'dyno proof' to back it up.

Why?

Eddy currents, aerodynamics, and pressure theory are some of the most difficult to prove equations that exist today... Essentially random at the best of times. The best general rule of thumb is that you don't want wild fluxuations in volume or pressure (those two being inextricably correlated), no intrusive objects into the air stream, and try to match the size of the IC piping to that of the turbo outlet and the TB as sil80 mentioned prior to this.

As long as you don't get ridiculous as go with 5" IC piping you will be fine.

-Dan

biggest reason i could see the "velocity stacking" would be using a bad bov that doesnt do its job properly... well kinds but ya im on the same page as you dan....