Red91vette

iTrader: (3)

I've been doing a lot of research lately and trying to find what turbo I should get for my 402. Basic specs are 6.0 iron block, forged 9.2:1, AFR 225, 236 242 .618 .620 114, stage 4+ T56, 9" rear, full suspension etc. The car is a street car rarely taking to the track. Would love to see 800rwhp on pump,1000rwhp on meth/race gas and 9s at 150 would be nice too BUT it's not most important, keeping this setup simple and on a budget is!

So what turbo on a budget for a 402? T88, S480, ST80? T4 T6? Doesn't master power have a T88 out? I like the price on BW turbos. Suggestions would be great since I am about to get my truck manifold kit started! Thank you!

venom ws7

iTrader: (13)

91mm......

XtremeDime

iTrader: (16)

I would imagine a t6 would be your best bet, a t76 would hold you over ok but you would limit that out really fast. Ever thought of twin t4s??

z28boysteve

iTrader: (9)

For a street car I would go with the turbo I have now, a PT88 good match for a turbo 402 street motor, if you're wanting a bit more, go for the PT88-42 I think it's called... that's the T6 version and it will give you alot more top end potential. the PT88 will give you a quick spool.

Red91vette

iTrader: (3)

Thanks for the replies. A 91mm would be sweet but pricey and more race then street IMO. I'd LOVE to do twins but again, that is more money and I am leaning towards a truck manifold kit that already has the piping done for a single turbo. I can weld and fabricate, I just don't have the tools to make the kit! I am really leaning towards a T88, I don't know if I should go T4 or T6. What about the BW turbos? ST80 S480? I really don't know much about them, some say they are better then T88, some say they aren't as good. I don't need every single horsepower I can possibly get, its a fun street car that can get the job done when needed, no dragster racing in competitions etc. Saving money would be nice since I just started my career and need to look into houses, I don't want to be that guy that has to sell his toy to buy the house. Thanks again.

ssnovaturbo

iTrader: (19)

S88 or GT47. I'm going with a S88 on my 402 in a 64 nova street car. Those are the two everyone on here told me to try. Both will make 800rwhp easily if the setup is right.

Red91vette

iTrader: (3)

Wow those are some big expensive turbos! I think that would be too much for me, both are rated at 1300+! I'm looking to hit no more then 1000rwhp on race just to say I have a 1k horsepower car. I'd run it in street tune 99% off the time at 800rwhp.

What kit are you running? T6 and wastegate size?

z28boysteve

iTrader: (9)

just because it COULD hit 1200 HP on a setup matched to it doesn't mean it will! A PT88 would be just right honestly, the very limit on how small you should go, so perfect for street IMO

Red91vette

iTrader: (3)

Agreed, I know that's max potential power. What's the difference between a PT88 and a GT47-88? Both are about the sane price, then the BW S88 is about 3-400 cheaper! Might just go with that, or a slightly smaller BW turbo, just gotta decide T4 or T6 for my hot parts kit. Thanks!

DrTurbo

iTrader: (3)

Go with a GT88. They are only $1250 and will make 1000rwhp and easily fit in a tight spot compared to the S88 and GT47 which are going to be larger units.

02SSLE

iTrader: (26)

PT 88 isn't a good turbo for your setup. The back preasure will be to high. I had a 403 8.5cr and had 65psi of back preasure with a cutout open. You will need twins or a bigger single.

DrTurbo

iTrader: (3)

Correct the T4 flange is just to small for that big of a motor.

Red91vette

iTrader: (3)

Wow, GT88 seems perfect! T6 flange, great power and pretty cheap! Only question is it worth it to go for the GT91? It's only $100 more, is it a lot bigger in size? What about power?

DrTurbo

iTrader: (3)

No difference in size. The GT91 just simply uses a larger comp wheel.

Red91vette

iTrader: (3)

So which would you reccommend? Is the 91 worth the extra $100 and will I see any significant gains from it?

DrTurbo

iTrader: (3)

You will definitely see gains.....question is do you need it? The 88mm will make 1000rwhp, the 91 will make even more. Where you might see the benefits of the 91 would be more rwhp with lower boost.

Red91vette

iTrader: (3)

Yeah, I like the fact of lower boost and more power. Just hope there isn't much of a lag difference. Sounds good, looks like I will be ordering a GT91 in the very soon future from you guys, thanks for all your help!

KissMySSo1

iTrader: (2)

an 88 would be at it's limit around 1000 rwhp. the 91 would have lower intake temps and make more power. def the way to go. it would spool very easy on a 402 as well

DrTurbo

iTrader: (3)

No problem. Also for you PT88 guys we now have a drop in upgrade that uses the PT88 Turbine housing. 91mm comp wheel and mid-frame comp cover.

Red91vette

iTrader: (3)

I'm liking lower intake temps, and more power for only $100 more? Seems like a no brainer. Thanks for the help.

So I am going with a truck manifold setup, hopefully fitting a 4" downpipe all the way back, I might have to get a turbo K-member for that though. My next questions are

what wastegate? 50mm?
Bov? Size?
Plan on fitting largest OBX A2A FMIC, will that be ok?
What size injectors? I also need to upgrade fuel lines, what ones? Pump is good though.
Need to do some research on the oil feed/return, any help would be appreciated.
Also what computer/tuning do I need? I don't know much about the electronics of boosting a car with the A/F.

Thank you for everyones help! Much appreciated! Hopefully get this project completed over the winter!