bser01

I've got a front mount turbo kit for my gto ready to install with a pt 76 gts
.96 turbine A/R and .70 compressor A/R. This will be put on a completly stock ls2. I've been told this is the best match for a stock cube engine, but will it be overkill for a non-forged motor? If i do decide to forge the motor it'll be about 2 years down the road. Since i will not be forging the motor boost response and not peak hp will be my primary focus. At what rpm will a pt76gts spool at with a stock ls2 motor? Would there be a better suited turbo that will spool significantly faster and still make 550-600 rwhp on a stock ls2? I will be pushing 8-10 psi max. Those are my goals for now because at the moment i don't feel like doing a crazy transmission/tire/fuel system upgrade but would like more power on occasion. Will a tc76mps fit my needs better or should i down grade to a 66mm turbo? Thanks in advanced for any help. Please throw some other options out as well if you think a different turbo will fit my needs better.

bser01

anyone wanna help, or am i going to get the standard, You need to search, response? I've seached and i didn't find what i was looking for.

Subliminal Hit

iTrader: (63)

seriously the info is all here and any question you could possibly think of can be found with patience. IMO a 76mm would be the smallest turbo I would run on a 364. Thats about the limit for a t4 turbo as far as backpressure goes from what I've read. A st76 would be great for that ls2 from forced inductions(t4), but a 76mps and a 76gts would work fine also. The 76gts will supposedly support another 40-50whp. And don't worry about spool time. Those are all fairly all small turbos and with a fm setup you will start seeing boost around 3000rpm in most conditions.

bser01

well reading compressor maps doesn't look that hard, can someone show me where i can access a database of compressor maps so i can pick one for myself? Specificly I'd like to compare the st76, 76mps, and 76gts, but would also like to look at a few 66-70 maps as well. From what i saw just initially looking at forced inductions.com if i don't plan on pushing more than 12-13 psi (which i don't) a 66mm turbo would still be operating very efficiently, plus i'd have near insta-boost.

bser01

i recall reading a post that suggested the 76mps will spool 4-500 rpms quicker than a 76 gts. Can anyone verify this from real world experience? If this is the case i will probably be looking into trading out my gts before the install/tune. From looking at compressor maps i see no reason why a 66-70mm turbo wouldn't do what i want on a non forged engine and still have room left over. Those saying a 66 is too small for a 364 i would like to hear some justification to this arguement.

Zombie

iTrader: (2)

with 6.0 liters you do not need to worry about spool time with a turbo as small as a t76. My rear mounted 76R with a ..96 a/r housing spools fast enough to loose traction on drag radials anywhere under 100 mph.

bser01

hey zombie i appreciate the feedback but that isn't really the answer i was looking for. I've seen many people talking about not worrying about spool time but they are concerned about turbo spooling at full throttle and on the drag strip. I have no intrest in racing at the strip, this will be a 100% street car. I'm concerned about part throttle response and quick spooling ability. A turbo that doesn't spool until 3500-4000 isn't acceptable for me as a street car, I'd like my power to come in quite a bit sooner.

Websy21

iTrader: (34)

I am interested too, I have the 80gts PTK kit.

Zombie

iTrader: (2)

My repsonse still stands, a t76 is small and spools fast on a 6.0. I hope you are planning on using an auto trans since you're concerned about lag. manuals spool really slow compared to an auto. I can stab the throttle in any gear and be at full boost before someone with a manual trans can finish their downshift (I can do it in 3rd then downshift to second while WOT for even faster spool). It takes me from 60-67 mph to go from 18" vac at light cruise to 20psi in 3rd gear (1:1), about 1 second (if I get traction and I usually don't). Spools faster if I'm in gear and under some load. I'm actually considering moving to a 1.15 a/r housing to soften the hit due to traction issues. Anything over 1/3 throttle results in boost building.

Websy21

iTrader: (34)

How do those high gears work for you? I thought that most use 3.50's and curious how they factor in for you. They obviously would help out for cruising on the highway with your th400 if you do that at all. But how do they perform on the track, spool, etc?

Zombie

iTrader: (2)

My best track time is in my sig. The car sees way more street time than track time, hence the choice in gears.

Websy21

iTrader: (34)

Thats what I figured, seems like you have no issues at all with spool time and power. Having an end result of frying the tires off I am curious b/c I think that the th400 is the best way to go for many reason's except for the obvious one of no o/d if you do some highway driving. Now most that ahve serious cars like these trailer to track and don't take on long hauls but some do and go with the 4l80e. I am torn b/w the two and if money was no object I think I'd go with the 80. Just curious, with those gears, what are you revving at when cruizing on the highway say at 60-70 or so. Thanks

nz12's

iTrader: (4)

http://www.turbobygarrett.com/turbob...o_tech103.html

there in there look for them

bser01

bump for some more opinions of a possible quicker spooling turbo, Also my car is a manual trans. Thanks guys.

67Firebird455

iTrader: (27)

I ran the MP T70, spools faster than a 76 trim, and still suppors 550 or so rwhp.

BlackySS13

I've got a TC76 on my 6.0L Silverado SS and boost comes in right around 2600 and full boost by 3200.

DrTurbo

iTrader: (3)

Yes we have had great sucess with the TC76's. They will make great power and spool very nicely. We have them in stock as well.

bser01

Ok guys i spoke with the boys at ForcedInductions and I'm going to swap out my pt76gts for a tc76. I'm needing to sell my 76gts but i can't post in the for sale section yet. Anyone looking for a 76gts? It has a .96 turbine .70 compressor. This turbo is brand new and has never been used. It came with my turbo kit which is why i'm swapping it out without using it. I'm wanting $1200 shipped OBO. Pics available upon request.

DrTurbo

iTrader: (3)

I heard the conversation about your car, and as low as your wanting your setup to spool, this is the best choice.

bser01

here is a pic of the turbo, additional pics and information available shoot me a pm if you have any questions.