Don't feel too bad, I tuned a guys car who had over 7 grand in a STS kit. 05 LS2 GTO with a T56. Modified STS kit with better intake piping and a big fmic. A-holes at STS sent 80lb injectors for their Garrett T04E 60-1 kit. Ya for scaling 80lb injectors on the E-40 PCM for a 420 rwhp car Car only made 420 rwhp on 7lbs of boost with 15 degrees of timing and mid 11's afr.

 

#1 need valve springs
#2 get afr @ 11.5
#3 get timing @ 17* at wot
#4 you can definetly raise boost level to 14-15psi w/no problem at all given the 317's on a 5.3l

 

i think my engine is just too low compression with the ls1 heads, would it be safe to go up to 14psi boost? once the meth kicks the car is running 10.3 AFR, i also have my old NOS kit the was on the car before.. so now im going to get the COMP Cams head upgrade kit which has new springs, lifters and pushrods and increase boost, would it be safe to spray 100hp wet with 10psi?

ideas....

 

also im running the stock STS turbo which is a 62 i think, do i need a bigger turbo?

 

You need a clue and a better thought out setup, but mostly a set of valve springs and a tune worth a ****.

 

1. new valve springs/ push rods
2. drop the meth
3. good tune

Check all your piping for boost leaks. Make sure boost is verified using a mechanical gauge. drop the meth because at somewhere around 9.0-9.5 compression(guesstimate) you shouldnt need meth at all on 10psi with a proper tune. that brings us to this, if you are really that low on compression i would start tuning for 10psi without meth and start bringing the boost on. You will see it getting better when the boost goes up due to the low compression. I am thinking it made "peak" power at such a low RPM because of your valvetrain. for all we know those ls1 valve springs could have 400k miles on them. Get these problems fixed/checked etc then let us know back.

 

valve springs need to go. forced induction actually pushes the valves open so you NEED stiffer springs.

most guys running 5.3s with the truck heads will run up to about 16 psi

you really need a real tune and the springs, first and foremost.

 

Not arguing just actually thought of this for my situation. Im running 7lbs and making 414/392 till 6k when it shifts on stock ls1 springs with 183k on them with no problems. My thoughts were the only springs that would be affected would be the intake ones being held open a lil longer due to the boost press, am I wrong?

 

ive read stock ls6 springs,, i kno there diff from stock truck ones.. but the ls6 was pused to 20lbs with a 88mm ,, build thread in here somewhere.. but def upgrade the stock truck ones to atleast ls6 ones..55 bucks brandnew..

 

what do you guys think of the COMP Cams Valvetrain upgrade kit part# 54200 it comes with with new sold lifters, or should i get only springs, also im thinking of increasing the boost to 15 psi

 

gota pull the heads to swap out lifters.. up to u.. i never swap out lifters... id use that money somewhere else..

 

Lunati dual valve spring kit 73925k1lun can be had for $210-220 and is a awesome set of springs unlike the mexican made associate spring junk in most dual kits.

Valve spings Dual Spring

Spring O.D 1.306

153 lb @ 1.810

400 lb @ 1.150

max lift .660

Lunati Intro Series valve springs are manufactured using the finest chrome silicon valve spring wire and manufacturing processes available. These springs were designed for use in your hot street machine or Saturday night bracket car. With a maximum lift capability at 0.660-inch, the Lunati kit serves the majority of popular camshaft applications.

The kit is complete with dual valve springs, steel retainers, locks, valve seals and spring locators and represents a drop-in installation for many popular LS applications. Lunati’s retainers and spring locators are CNC-manufactured from 4140 alloy steel. The locators pilot onto the valve guides and locate the inner diameter of the inner valve springs, preventing them from abrading the spring pockets in the aluminum heads.

In common with all dual-spring retainers, these new Lunati types have a group of steps machined into their underside (which locate the upper registers of the valve springs) and a bore machined to accept the 7-degree valve locks. The locks are equipped with inner bead locks and the 7-degree interference angle between the locks and the retainers is favored by many who believe it causes the locks to clamp the valve stems tighter. Through careful CAD and FEA design efforts, Lunati engineers have developed a new valve spring retainer design using wear-favorable alloy steel, yet nearly matching the weight advantage of Titanium.

For street/strip longevity, Lunati’s lightweight alloy steel retainer is unbeatable. Viton steel-jacketed valve seals complete the kit. The steel jackets ensure the valve stem seals remain tight around the valve guides and also protect the seals should the inner springs come in light contact with them. The Viton material is ideal for resisting heat and oil, particularly some of the more aggressive oil additives that cause ordinary seals to swell and distort.

 

first off I agree with every setup is different but we cant tell without a graph or seeing what its doing on the dyno. 2nd, I cant tell why yall think he has 317's. I didnt see where OP mentioned he had 317's. In fact in the original post he said it had ls1 heads. I know it dont seem like a big deal but 317's @ 71cc's would net him around 8.7cr and ls1(806,853,241) @66.6cc would net more like 9.3cr on a stock 5.3. So I am guessing you wont need to boost to the moon to get any power. This is a very vague way of telling me there is a different problem I.E. springs, boost leaks, poor reference, valve events, poor tune etc.... Good luck OP

BTW OP please post a graph

 

the turbo van.....with the stock 5.3, 317's, z06 cam, run a 72 mm turbo at 18 psi on 91 with water/meth. It makes around 700 to get the et's at the 6500 lb race weight. Even with the cam....it only makes 5800rpm.

Im surprised no one posted about the turbo......sts.....lol......probably a 60-1.....

 

1. get valve springs
2. drop the meth
3. get a good tuner

 

Get your AFR's up to the low/mid 11's. you're drowning it. And get some valve springs.

 

it would be pushing the intakes open while the exhausts are open too

 

a camed 5.7 with exhaust can make that power. Check your timing maps and fuel maps.

 

imo so far all the suggestions in this thread are good and things i would do if i was you, and i would not worry about your heads since they should put you at 9.1 comp ratio.
but i do not believe what has been stated so far is your problem.
i believe due to that fact you made peak power at 4800rpm and your using a very small turbo that you are having high backpressure issues, which can amplify every other problem that you have (like valve springs), i would install a pressure gauge pre turbo to verify what your backpressure is before doing anything else (with a check valve so you know what it peaked at)
second thing i noticed is you did not mention anything about your trans, stock auto trans barely hold stock power, so its also very possible that your having trans slip combined with everything else thats happening
has your tuner street tuned your car at all? first your car should have never seen a dyno without first street tuned and if it was street tunend first then your tuner should have know there is problems with the car

 

A bolt on 5.7 can make that LOL. Honestly, I think it's just a lowsy, mismatched setup. Something major is up here especially at 10 lbs of boost. I really don't think we have enough info to help you out with the problem. And I think I remember you saying you didn't have a boost gauge?? A boost gauge is like $70! Get one on there and you'll know what your making for boost, not just relying on the tuning software.

You using stock plugs or have you gone colder? Not revving past 4800 leads me to believe you have a major ignition problem. Any CEL?? Are all the coils actually firing? The turbo is not going to magically make the car not rev past 4800 so check all your basics first.