gti-r t28 vs. s15 t28

[cheez80]

i know this much so far:gti-r t28 has journal bearings15 t28 has ball bearing center cartridge

is there difference in compressor housing sizes? it seems that guys running gti-r hit higher max hp?

*shrugs*

help me sort it outt!

[RMiller]

The GTiR has a t3 compressor housing, while the S15 t28(and s14 t28) has a t04b housing. The compressor flows 33lbs/min(although I think I've seen different numbers depending on the source) and the s15 flows 31lbs/min, according to cheapturbo.com. The turbine has a/r .86 on GTiR vs. .6x on S14/5, which is probably where the power comes from. Check out cheapturbo.com and you will find info you are looking for.

[Hijacker]

i would imagine though with the larger compressor, slightly larger a/r, and journal bearing that the GTiR's T28 spools slower than the S15's. Power versus point of delivery.

I wonder if the GTiR has the same T28 off the skylines.

[RMiller]

Hmmm, maybe it is the same compressor.

Yup, it spools slower and makes the additional power higher up. I don't know how much difference the ball bearings make in spool up, but they are definitely good for transcient response. Like, you give throttle, let off, then give throttle again. Since the turbo just keeps spinning, it starts from a faster speed and builds boost faster.

[cheez80]

ooo, good discussion

thanks guys

would any of you have dyno charts comparing the two?

just curiousss

[gerbort]

ooo, good discussion

thanks guys

would any of you have dyno charts comparing the two?

just curiousss

I 'd like to see that too...

[Beemen550]

well thats nice to know i got a gtir t28 but i didnt know if it was as powerful as the s15 t28 so i wasnt gonna use it, so what is the maximum boost that both of them make? if its 17psi or over i will probably use it but if not im go sell it

[Beemen550]

anyone know what the maximum boost the gtir t28 can handle?

[RMiller]

Probably around 18 psi.