NYSS Guy

iTrader: (1)

This is just becoming comical. You know what, you're right. 160 degree IAT's are not the problem. The pcm pulling a ridiculous amount of timing is not going to hurt power. Stock valve springs aren't going to hurt either.

The scans that you posted are in two programs that I don't have on my laptop, so no I didn't look at them. The point is, I don't have to look at those scans to know that there are some very obvious things wrong with this car. And I can completely understand why you wouldn't want to take advice from people that have been working on and tuning rear mount LS1's for a few years now.

To the OP, since you are going to have to start looking for a shortblock in the near future, take a look at LME. They are a sponsor, and know their stuff.

Out of morbid curiosity, what are your ambient temps when you are making these pulls?

Not many people have mentioned backpressure because the owner of the car mentioned running a .96 a/r. There shouldn't be any issues with backpressure.

Zombie

iTrader: (2)

FWIW, i've measured the back pressure on my setup with a .81 a/r housing and a .96 a/r housing. The housing was the only change to the setup.

.81 a/r housing 15psi boost = 40psi backpressure
.96 a/r housing 15psi boost = 37psi backpressure

Turbo is T76 from innovative with an R trim turbine wheel 1.00 trim, big heavy ****. 3.5" V-band.

I haven't remesured pressure since all my changes, but it's definately lower because i've picked up about 100 rwhp around the same boost level. Went from 127mph to 131mph at 15psi in horrible weather. I'm rolling with the .81 all the time now since it's a bit more fun on the street. Biggest effect on backpressure (this is speculation haven't actually measured it yet) was when I went from 3" exhaust after turbo to 4" exhaust. Necking down the 3.5" outlet to a 3" exhaust turns out to be a good recipe for backpressure and slow spool.

Just figured i'd add this info for anyone who reads in the future.

Public

iTrader: (19)

Many of these kits came with a .61 a/r on the base 60 turbo as reported by others and mine was .61 as well. GT 70 was .81 a/r. Theirs a range that works and i think STS just gets a turbo in that range when its time for more turbos. I would think .96 a/r a bit sluggish and boost coming on a lot later but that's the one housing in the range STS's come with i have not tried.

99camarosupersport

iTrader: (6)

My GT-67 has an A/R of .60? Atleast so the casting says.

JAvenger007

iTrader: (9)

are you sure thats the EXHAUST housing and not the compressor?

99camarosupersport

iTrader: (6)

Actually it's the compressor. On the left looking from the rear of the car. My fault.

darkhorizon

You are retarded, go away.

NYSS Guy

iTrader: (1)

Hey Zombie, this is interesting info. But I don't really know what it means in the real world. I have a similar turbo, it is a little different. So, if I was seeing 37 psi of backpressure at 15 psi of boost....what does that mean? Is it high, low??

Zombie

iTrader: (2)

Too much backpressure = lower power and slower spooling. I've talked to engineermike about this. My backpressure use to be about 3:1 and 2:1 is considered good for a street car. Backpressure causes problems, it's best to reduce it as much as possible with reason.

NYSS Guy

iTrader: (1)

Okay, that is good to know. How do you measure it?

99camarosupersport

iTrader: (6)

Then why for the STS kits are manifolds and 2.5" piping better for boost, where is the breaking point for this in relation to boost/power.
Just going by that logic there it flip flops all i've read about that with these kits.
Logically in my head it seems like more back pressure on these kits would equate to faster spool times period? wrong?

2000TurboVert

iTrader: (17)

I might be wrong, but common sense tells me Less Back pressure.. More flow????

mycar2fast

iTrader: (1)

just to clear things up, I'm the owner of this car, and I'm not dissagreeing with anything I've heard, I'm def ordering some comp 918s and new fuel pump and injeftors, and fmic is also on the way....

NYSS Guy

iTrader: (1)

That's good to hear man. I know it sucks to spend all that money at once, but it will save you in the long run. I'm telling you, these setups are very picky. It only takes one little thing, whether it's mechanical or in the tune, and it throws everything off. You have a few things working against you right now, so you just need to start eliminating the bad things...and you're already doing that.

I would still suggest starting off a little lower on the boost when you get this stuff in. Make sure everything is running right at 5 psi before turning it up. But with the stuff you're getting, you should be able to run 8 psi all day long (with a good tune).

Good luck man, and as I said, pm me anytime. I'm not an expert, but I have learned a lot from my mistakes.

NYSS Guy

iTrader: (1)

By the way, where are you located?

mycar2fast

iTrader: (1)

im in michigan

99camarosupersport

iTrader: (6)

I agree, but wouldn't higher gas pressure be better for these kits?
I'm not sure if you had a sarcastic or smart *** reply directed towards me in that post, but if so it was an honest question.

I've always read about keeping the stock manifolds with this kit and stock Y pipe. Just checking to see if this is really the way to go before i get rid of my longtubes and 3" ory.

2000TurboVert

iTrader: (17)

NO I was not being a smart ***... That was sincere..... I think the stock manifolds is all about HOLDING IN heat, instead of having it dissapated with ceramic coated longtubes......

I dont know much about the back pressure issue!!

99camarosupersport

iTrader: (6)

So I guess I should just stop asking questions and rest assure with the fact that I need to do away with my LT's and massive ORY and go back to stock?

I just hate to do away with one to find out later they had their perks also, I'm too poor to afford LT's again any time soon. lol

enginjoe

iTrader: (11)

It's been proven over and over. Go for it.