hak

I have installed an STS turbo system on my 2002 LS1 6sp. I installed the system in 2008 with a 7# wastegate spring. I was very satisfied with the 455 rhp it produced and have enjoyed the fun for several years. This year I decided to add more fun so I installed a Comp cam .61 lift, Patriot springs, Smith Brothers thick wall push rods, Melling high performance oil pump, Katech C5r timing chain, 10# spring, and a Kenne Bell boost a pump. For all that I get 480 rhp. My tuner, who is the very best Dr. Phil, said he tunes a lot of these STS systems and they all have a problem with the turbo exhaust housing being too restrictive. He suggested that a buy and install a larger exhaust housing which I intend to do.
I am looking for all suggestions to get the most hp out of this STS system.
Thanks,
Howard

indirocz28

Find out the sizes of your turbine housings. They will read in .xx a/r. That tells you the size. if you are running a .6x a/r- go up to .86 a/r. However, keep in mind that changing the a/r for the turbine housing changes the spool range, and if you have a larger compressor wheel you may not want something like a .96 or 1.00 a/r turbine housing.

hak

Thanks for your help.
Can I buy these turbo housings directly from Garrett ?

Hammer

I have a forged 383 with stock heads/cam running 10-12 lbs putting down 670 rwhp using the stock housings the GT32 turbos came with 5-6 years ago.

Jim

StatmanRN

STS apparantly used a variety of makes and sizes, but all were on the smaller side to help reduce the lag inherant in a rear mount system. Mine uses upgraded slightly larger BBW bullseyes.
Power seems low for 10# boost. Lots of people have made more than that with the STS supplied turbos.
How is the IAT? And was the system actually tested for back pressure upstream? Do you have 1 wastegate or 2?

indirocz28

I agree, this car should be close to 6xxhp on 10#s.

Yes you can buy the turbine housings from garrett. They range from $80-$260 depending on turbo and size.

Check for leaks and high intake temps as mentioned before. Heat is a killer while trying to gain performance.

hak

I have one wastegate . It is one of STS first systems. I bought it in 2007. The exhaust a/r is .36. My tuner does a lot of turbo tuning, he did not check back pressure, but could tell from the way it died that it was the exhaust housing. What does IAT stand for?

hak

Thanks again. My tuner did not tell me the IAT, but I know he checks it.

indirocz28

IAT is intake air temp, and if your exhaust turbine housing is .36 a/r then HOLY HELL, that thing is TINY. WOW! That sounds way to small in my opinion...

Ashc2025

I'm running the exact same turbine housings, and with 7# springs. We threw a boost controler on it and pumped the boost up with no trouble, they actually hit about 10 Lbs on accident and we dropped the RPM immediatly, but i was at about 5k. (We were tryign to hit 7#) But the dyno read about 560 ish if I remember right.

There is a lot of backpressure, it's almost a little irritating in the lower RPM when your putting allong at 25MPH or so. Pops quite a bit. One thing I did was wrap the pipes from the headers back. I'm running stock shorties too. I have a set of .68's for the turbine side, but the turbo lag is pathetic, almost unusable unless you're on the strip.

hak

I have been looking for something around .56 for the exhaust housing. Where did you buy your .68 ?

johnglenntwo

I have to check my housings, but, they originally said they were good for 700. I have an 02 Z06 with a original 2005 STS system. I'm sure I've seen 600lbt on a 30.6BP day @5000rpm @8.5lb (In 4th gear it felt like 3rd). It was tuned at 543/525 @7lb with 42lb inj and a boost a pump. Also, I think they went to the smaller housings for CARB approval, and quieting. I also have to say it ended up working out pretty well. In the summer I can carefully use the 7lb in 3rd gear. In the winter it goes up by itself and 4th gear does the same job without having to worry about the wheel spin! I could have died figuring that stuff out!

johnglenntwo

It is a/r .48 and that seems consistent! But, I also found some oil on one of mine that wasn't there before so I'm glad I looked! My pump is original and I have been running it on low, but, after 7-years I have finally found out not to.

Also my turbos don't spool until 3k, yours should come on around 2.5k, or so. I don't miss it with high flow cats, smokes umm right away.

redneckvette

smokes umm with right away.[/QUOTE]

Uhhh?

lingenfelter200

Why don't you go for Precision Billet CEA 6266 Turbo 750hp with your setup as my friend did with his C5
He is using Precision Billet CEA6766
http://www.youtube.com/watch?v=5ykStxanS2s&feature=plcp

johnglenntwo

Uhhh? [/QUOTE]

Typo!

Also check these out, since, with the larger turbine housing and high flow cats you would need quieting.

http://i123.photobucket.com/albums/o...sulekg/002.jpg

They are spring loaded and I now have added some holes, since, they were cadillac quiet without them. I also went back to the stainless steel unpainted plates, and it looks better. I listened to somebody online and they were wrong. And you need the backpressure to get going! STS said the smaller housings are more fun even though they couldn't make as much power. My supertraps are more fun, and more dynamic, plus they can be swapped out in 5-minutes!

johnglenntwo

Are these really a direct replacement in a STS system?

lingenfelter200

No, it's HP Performance turbo kit. I was talking about the turbo performance, to install it in his kit.