sage of the 7 paths

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?

FrankV702

iTrader: (14)

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?

btbaus

iTrader: (3)

post in the single turbo forum

FrankV702

iTrader: (14)

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!

arghx

iTrader: (3)

you need something externally wastegated.

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

Turblown

iTrader: (12)

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.

FrankV702

iTrader: (14)

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..

solareon

iTrader: (1)

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.