what specs?

[S13Sil-line]

I have an RB25DET, and am replacing the turbo. I'm building the car for drift and want a fast spool up. What compressor trim and turbine housing would be best?

50 a/r trim, 60 a/r trim.48 housing, .63 housing

[Project240]

Generally speaking, you want a larger compressor A/R and a smaller turbine A/R. More power in the middle of the band while sacrificing some breathability at high RPMs. Maybe a .63 or .60 comp A/R, and a .48 turbine A/R or something not much bigger.

[hannibal]

I assume youre looking for a T3/T4T3 turbine is available in 0.48, 0.63, 0.82 A/RT4 comp is available in 0.50, 0.60, 0.70 A/R, IIRCT04E comp wheel is available in 50, 54, 57, 60 trim

[S13Sil-line]

No I want a T3. Not a T3/T4. I know already know whats available. I want to shoot for 300hp with a fast spool up.

[hannibal]

What compressor trim and turbine housing would be best?50 a/r trim, 60 a/r trim

"a/r trim" is a meaningless term.

My $0.02...Since most people say the 0.63 turbine A/R is a good compromise between lag and top end flow, I would think the 0.48 A/R will provide quick spool up. Top end might suffer. The 60 trim and super 60 wheels look good on the compressor maps.

Project 240, can you explain how/why a larger comp A/R provides less lag?? Ive been thinking a larger A/R would increase lag.

[BoostFab]

No I want a T3. Not a T3/T4. I know already know whats available. I want to shoot for 300hp with a fast spool up.

you are spending $, why not spend on a turbo that have more potential down the road, when you have more boost urges. i think a t3/t04e (or Super-60) would be a nice one. just regulate the amount of boost to the power level you want. IMO, it's better to run moderate boost to meet your power goal on it, rather than over work the smaller turbo to yield the same amount of power.

my $0.02