Small T28 vs. Big T28

[pboglio]

Anybody out there know what the exact difference is between a small T28 and a Big T28? FP stated a few years back on their website that they used a 62 trim compressor wheel and a 79 trim turbine wheel on their small T28. Now the only 62 trim wheel I've seen a map for is the Garrett "Disco Potato" rated 35 lb/min @ 14.7 psi and 38 lb/min choke flow. My FP small T28 exhaust wheel has 10 blades and the FP big t28 pictures I've seen had 9 exhaust blades. Is the only difference in the exhaust wheels? Thanks.

Gene

 

[98eclipseRS]

First off its not a "small" t28 its just a t28. And again its not a big t28 its a big28 they are different. So let's get started here, a t28 is just slightly bigger wheels in a t25 housing, think 16g compared to big16g not that much difference. Personally I think a t28 is a waste of money but that's another story. A big28(what fp sells) is basically the equivilant of a 16g in a t25 housing. The housings themselves are extremely ported and the wheels are significantly larger than the standard t25 or t28. So to answer your question no the wheels are not the only difference. The ehaust housing is larger and the compressor housing is ported to beyond and back, and the wheels are much much larger.

 

[pboglio]

Zach,

Thanks for the clarification. But stating that the wheels are much much larger is kinda vague and no you didn't answer my question. What is the compressor wheel trim for the FP Big28? These are the specs I've seen stated:

FPT28/28
62 trim compressor, 1.86"/2.37"
.48 A/R Compressor Housing
79 trim turbine (10 blades), 1.86"/2.09"
.49 A/R Turbine housing not ported

FP Big28
"?" trim compressor,
.48 A/R Compressor Housing
76 trim turbine (9 blades), 1.85"/2.12"
.49 A/R Turbine housing, 7 cm ported.

My FPT28/28 is reaching its upper limit (319 w.h.p. via Dsmlink). I just don't know if the compressor wheel has more in it or if the turbine wheel is causing high backpressure and holding back the turbo. If the only difference is the exhaust wheels than a turbine wheel clip would be a cheap fix for me. From seeing detailed pictures of a FP Big28 exhaust wheel I would guess it has less backpressure since it runs 1 less exhaust blade than a FPT28/28. One question though, why would you say a T28 is a waste of money? Have you ever run one before? Maxed out it looks like a 380-400 crank h.p. turbo with very quick spool up, whats not to like.