what i am looking for is a turbo that spools up before 4300 rpm and can give me 375 to 385 hp to the wheels. i have a streetport doen to the motor and plan on runing haltec. after some phone calls with some tuners these are the turbos i am looking at.

Garrett GT2876R (aka GT25/40R)

Turbine
-Wheel: 53mm w/ 62 trim
-Housing: .64 ar, .86 ar
-Maps

Compressor
-Wheel: 76mm w/ 48 trim
-Housing: .70 ar
-Maps


Garrett GT2871R

Optional "T3/T4 drop-in" style turbine

Turbine
-Wheel: 53.85mm w/ 76 trim
-Housing: .86 or .64 ar
-Maps

Compressor
-Wheel: 71mm w/ 56 trim
-Housing: .60 ar


Garrett GT2871R turbo with GT28R style Compressor

Turbine
-Wheel: 53.85mm w/ 76 trim
-Housing: .86 or .64 ar
-Maps

Compressor
-Wheel: 71mm w/ 52 trim
-Housing: .60 ar (2 bolt inlet and 3 bolt outlet)

witch is better ?
p.s doest any one have a GT35? and if so how fast does it spool up?

 

With all the above mentioned turbos, you're right around the 65% efficiency range at 15psi. Anymore boost, and you're not even on the compressor map anymore. IMO, they're all to small.. You should look into a GT3076R 76.2mm, 56 trim, .60 A/R. You're in about 72% efficiency range at 15psi, which is pretty good. You sure you want to stay with the smaller T3 rear housings?? Maybe a .84 A/R T4 turbine?

 

post in the single turbo forum

 

With all the above mentioned turbos, you're right around the 65% efficiency range at 15psi. Anymore boost, and you're not even on the compressor map anymore. IMO, they're all to small.. You should look into a GT3076R 76.2mm, 56 trim, .60 A/R. You're in about 72% efficiency range at 15psi, which is pretty good. You sure you want to stay with the smaller T3 rear housings?? Maybe a .84 A/R T4 turbine?

I don't have a GT35R turbo, but I can tell you by looking at the compressor maps, they're pretty well matched for a 13BT. I've ridden in a few FCs with a 35R as well and spool was pretty great!

 

you need something externally wastegated.

GT3076 would be the absolute smallest I would go, with the biggest turbine housing you can get for it

 

Don't use any of those on a rotary, you're going to chock the engine up top.
BB Gt35R will do the trick and be at full boost in the low to mid 3000s...
or a 60 trim to4E BB( full boost in the 2900rpm range),but will take around 18 psi to net 385rwhp. The Gt35R will do it around 14psi.

 

What he said..

With the turbos you listed, basically, the engine is going to be requiring a lot more air than what that turbo can put out. It's going to be over working the turbo, in turn heating up air. You'll start pre-detonating.. Not good.

Yes, that should be the absolute smallest you should go with as far as BB GT series turbos. They do make it with a 1.06 t4 turbine. I actually considered it a couple of times, BUT the GT35R is like $60 more.. I really like the T04Z turbo as well..

 

Get the GT35R kit from A-Spec (check their forum on here). Comes with everything including a downpipe so you can rock and roll with the quickness.