Sts
Thread Starter
Teching In
Joined: Feb 2005
Posts: 34
Likes: 0
From: california,
Sts please help I'm having fule probs with my sts kit on my 00 gmc. I did my first dyno pull yesterday and got three different pulls. first was 302hp368tq 2nd was 310hp 457tq 3rd was 269hp304tq. I know my hp shouldbe better than that. this is on a 5.3. I also have the high boost kit with meth inj but I havent tried either untill it runs good. I also have nelson performance tune and 373posi. nelson says i need a fuel pump and 42# injectors. any help would be great. this is my 1st turbo.
Last edited by luv4pits; Feb 10, 2005 at 02:10 PM. Reason: diden't finish ?
310/457, is that correct. Way too much torque for a stock 5.3 at 5psi. I think they should be in the 325/375 range. If you need pump and injectors, you shouldnt be running hard on the dyno. The lower numbers for the 3rd run could be from higher intake temps. Get with Allen and he will get you fixed up.
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12 Second Truck Club
Joined: Feb 2002
Posts: 5,574
Likes: 0
From: Sacramento, CA
I think you just need more tuning.
On 5psi with a cam and headers on an otherwise stock 5.3L I made 343rwhp and I can't remember how much TQ but it was around 370. I don't know if we were using any methanol on the run or not but I can tell you that the AFR was perfect but we didn't know how to tune well at the time so who knows what the #s could or should have been. Higher? Lower? Not real sure.
I'd say get the injectors and such in and work on the tune. The 6.0L guys are about 360-380rwhp on 5psi so you should hopefully only be about 30rwhp peak lower than those guys
Keep us posted and if you want any advice don't hesitate to ask. Just form the question better. :p
On 5psi with a cam and headers on an otherwise stock 5.3L I made 343rwhp and I can't remember how much TQ but it was around 370. I don't know if we were using any methanol on the run or not but I can tell you that the AFR was perfect but we didn't know how to tune well at the time so who knows what the #s could or should have been. Higher? Lower? Not real sure.
I'd say get the injectors and such in and work on the tune. The 6.0L guys are about 360-380rwhp on 5psi so you should hopefully only be about 30rwhp peak lower than those guys
Keep us posted and if you want any advice don't hesitate to ask. Just form the question better. :p
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Teching In
Joined: Feb 2005
Posts: 34
Likes: 0
From: california,
Thanks for the replys. I'm not much the computer guy so sorry about the ?. My Air Fule Ratio was 10.9 at 4000 rpm but climbed to around 13.5. It pulls like crazy in 1st but then it falls on it's face. I can't wait to get it running good at this boost so I can try the high boost switch and the meth inj. Thanks again
TECH Enthusiast
Joined: Oct 2003
Posts: 729
Likes: 0
From: Bakersfield, Ca.
I couldn't recommend for your truck. Call Thunder Racing tomorrow. If they can't help you, they know who can. Synergie is good too and they are in Nor Cal. Both are sponsors and carry STS kits and known for their good customer service.
Good luck.
Good luck.
12 Second Truck Club
Joined: Feb 2002
Posts: 5,574
Likes: 0
From: Sacramento, CA
The 8.1L Marine injectors will work great. They are rated at 43lbs and run about $400-$420. Most buy them from Arizona Speed & Marine. The fuel pump is a simple inline 255lph pump (about $150-$170). I got mine from Thunder Racing I think.
You really can't use any other injectors in yuour truck because they are different than the LS1/SVO style injectors and would require modifying the harness and clips to get other types to work.
You really can't use any other injectors in yuour truck because they are different than the LS1/SVO style injectors and would require modifying the harness and clips to get other types to work.
I never had my truck on the dyno, but it felt like what you are saying. Ran great 1st and 2nd, but fell on its face in 3rd. It was leaning out with the stock injectors. 02's read .900+ and then fell into the .700's in 3rd running out of fuel.
Since I upgraded the injectors, it now pulls great in all gears and 02 sensor voltage stabalized.
Since I upgraded the injectors, it now pulls great in all gears and 02 sensor voltage stabalized.
Thread Starter
Teching In
Joined: Feb 2005
Posts: 34
Likes: 0
From: california,
Thanks for the help. I just ordered the multec 2 43# inj from az speed & marine and nelson is sending out another tune. I called le-toy motorsports and it was a dynojet dyon used on my truck. He said it puts load and calculates in the weather and everything. Thanks! Hopefully I have more #s in the coming weeks.
TECH Fanatic
Joined: Apr 2003
Posts: 1,109
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From: Albuquerque, NM
Keep an eye on your boost levels both on the dyno and running down the road. I had lots of trouble building boost when the truck was cold or after the turbo cooled off from sitting/waiting.
GTech is a nice reference but I would not trust it too much.
GTech is a nice reference but I would not trust it too much.
14 Second Truck Club
Joined: Dec 2003
Posts: 1,188
Likes: 0
From: Houma, Louisiana
You may be getting false knock. 99 and 00 Had issues with false knock. Mine was pulling about 7* timing and killing my power. I swaped to an 02 PCM and it solved all the problems. Call Allen, he can fix you up.
On The Tree
Joined: Feb 2004
Posts: 184
Likes: 0
From: Salt Lake City
Talk with Allen, if you have the fuel there but you're still leaning out it's probably the tune. Do you have access to a GM Diablo Predator or another ahnd held, that would let you know real fast if your'e getting any knock retard.