98Zeric

I contacted VS Racing for recommendations for a turbo to go with, In the email I included all the details of my truck and what the intended use of the truck, They replied with their 80mm T6 1.32 AR 96/88 turbine wheel. I don't know much about turbos, obviously, but that size seemed little bigger then what I thought I should look for, But I bought it anyway haha. So for peace of mind, I'd love to hear some feedback on the sizing.
Vehicle is a RCSB CHEVY, Awd, auto w/ 2800 stall, 80/20 (DD/TRACK), the motor is a built 398, 11-11.50 compression, SS2 cam.
thank you

theunderlord

That T6 housing is huge, nothing wrong with that of course, but it makes packaging a little tougher. T4 would have been a little easier to cram in there, you didn't mention what year truck? GMT800? 900? That size Turbo is capable of 4 digit HP numbers no problem, so start getting $ for that trans build. You thought about piston ring gap at all? Also, that CR is pretty darn high for a forced induction engine.

ElQueFør

I run a T6 S475 in my 90 OBS RCSB. LQ4 with SS2 cam. T56 Trans and 4.88s.

I LOVE the performance of that turbo.

That compression ratio you speak of for your combo is not ideal for boost. Compression makes power. But boost makes more.

98Zeric

GMT400, the truck is a 94, lol I'll replace the 60 for a 4l80e , the compression is on the high end for sure. I don't plan to run much boost, I am concerned with ring gap, I was hoping with lower boost would help

98Zeric

hmm, maybe I should consider lowering compression. Seems thats the concern more then the size of turbo i have

jordoza

If your willing to run e85 then that compression should be fine.

theunderlord

word, you said “awd” so you must mean 4wd? The OBS trucks have gobs of room in the engine bay, so fab, while never a slam dunk should be at least a tad easier.

98Zeric

No, i made it awd, I used the front axle from a 01 escalade and used NP149 transfer case..also converted to dual piston calipers (unrelated to awd conversion) from the 99-06. There is room, i am thinking behind the AC compressor, the turbo is a bit big, but i think I can make it work

98Zeric

Yes, I ran the wire for a e85 sensor. How much boost would consider "safe"?

theunderlord

Very very cool! similar to the red truck they built on power nation years ago, and that Orange wrapped NBS LT Tolman has going on his channel right now. You should make a build thread in the Conversion and Swaps forum if you have pictures of the process.

98Zeric

I do have some pictures

ddnspider

iTrader: (26)

What's the power goal when you said you don't plan to run much boost?

jordoza

that answer comes with the qualifier of how good is your tuner. Ive run 21psi plus on a 12 to 1 engine on e85 but my tune was spot on. The higher your compression ratio the smaller your tuning window but with e85 it's still a fairly large window. whats your hp goal if I might ask.

gametech

iTrader: (1)

A baby sized 67MM turbo is a well known application for an lq9, because of a kit some years back. Such said kit would easily brake boost over 7lbs of boost and insta spool off the converter.

98Zeric

don't really have a power goal,whatever i can safely and reliably make, to the motor..have in mind around 10lbs

Tuning aspect of it is important, Being in the business I'm in, i know of a few tuners, i think I'll be ok with the tuning part.
as i mentioned in the reply above to ddnspider, i don't really have a goal, the most i can get safely and reliably (to the motor). But if i had to put a number around 700hp would be pretty cool

jordoza

I'm thinking 10psi would get you 750+ at the flywheel. That is doable for sure on e85. That is figuring 450 on motor alone. That is a low estimate but I figured for worst heads possible. I always try to err on the low side. Under promise and over deliver. The turbo you bought will easily do way more. 4 digit power is possible with a s480. Rwhp I'd rather not even try to guess since it's awd and the drive train loss is going to effect it alot.

98Zeric

think the motor made around 450 to the wheels in the 99 trans am i had,with auto and 4000 stall. However that was with a tick SNS tourqemax stage 2 cam. I now have ss2 in there now. I agree, it is best not to get hopes to high, lot of variables that will affect overall out come... loss through drive train being one. I have some ported 799 with Ferrea 2.02/1.60 valves. So if the 11.5:1 compression is a wise choose I'll stick with those heads, if i swap out a set with 72cc chambers, compression will be 10.5:1 +/-.. I'll definitely keep my current turbo, from the feed back you guy's have given me

SLOW SEDAN

iTrader: (13)

OP - Please don't put a baby turbine T4 turbo behind 398CI, even the 88/96 turbine is kinda small for that engine size. If sticking with VSR their 85/102 would be about the smallest thing I would want on a 11:1 398.



Not sure why so many people want a lazy engine with a turbo, compression works great with boost.

98Zeric

The turbo i have has the t6 flange,that was my thought for a higher compression, to get away from a lazy motor, however my motor is closer to a compression of 11.55-11.65, I'm beginning to worry my current compression might be to high. i was shooting for up to 11:1... thank you for the recommendation

SLOW SEDAN

iTrader: (13)

Since you ran a flex sensor I assume you have E85 nearby, E loves compression even without an intercooler. 700hp will be silly easy even with the smaller 80/96 turbo.