fstr n u

Any advice would be great, positive or negative.

Car is a 1998 Chev Camaro Z28 with the 346 LS1. Running a set of TSP PRC Stage 2.5 5.3L heads (combustion chamber 62cc vs 66cc stock LS1 head), Comp Cams 230/224 111LSA cam, LS6 Intake, Long Style Headers, Ported stock throttle body. Moser 12 bolt rear end 3.90 gears, rebuilt 6 spd tranny and the list goes on.

Installed STS GT-67 turbo kit on car w FMIC (no meth inj yet). Within 100 miles, engine went kaput. Cylinder #7 now missing some of the piston.

Need to sort out what to do while keeping costs to a minimum. Goal is to run 650-750 crank horsepower max. Can this be done on an aluminum LS1 (346ci/383ci/393ci) engine with forged internals and PRC stage 2.5 5.3L heads with a proper cam and meth injection? My car with h/c/i was just under 500 hp crank and stock internals.

Any advice would be welcome and appreciated (i would prefer to stay with the LS1 as i can reuse heads and don't require a conversion kit for the LS2 style engine).

RS_SS69

iTrader: (31)

Stay stock cubes, just put in some forged rods and pistons.

Go callies compstar rods

Diamond or weisco pistons

Turn the boost up and have fun. Can easily reach your goal at 10-13psi.

Adam86

iTrader: (10)

I would say you should sell the 5.3 heads and pick up some cheap 6.0 truck heads. Drop that CR and turn up the boost! Plus you'll definitely come ahead on selling those 5.3s.

Bob@BruteSpeed

iTrader: (16)

I agree as it is much better do drop the compression ratio by swapping out the heads, than it is with dished pistons. Basically you want a flat top piston with a lot of material above the top ring. Bob

fstr n u

Thanks for the input guys. I just read an interesting link on the forced induction link on this website that suggests that a properly built forged internalled 347 should be able to meet my goals. A 383ci with forged internals in my mind would be able to meet that goal a little easier. At least i know i'm on the right track.

I will certainly look to meth injection and will look into head options and some of the differences between my PRC stage 2.5 5.3L heads and the 6L heads.

You guys have some crazy *** fast builds going on.

Watch out Bugattis and AWD Lambos with forced induction!

tpunk

iTrader: (8)

You would also stand to benefit from selling your long tube headers and putting stock manifolds back on and wrapping the exhaust to keep the heat in. The turbo will spool much quicker than with the LT's.

fstr n u

Do you know how much that would assist with the turbo spooling? Are we talking 200rpm sooner or 1,000rpm sooner? Would utilizing a stock manifold and smaller exhaust tubing necessitate a different cam at all or cylinder head selection for a rear mount turbo?

Would i be wrapping the tubing that comes off the exhaust back to the turbo, or from the turbo to the intake?

Sorry about my lack of technical knowledge. Still learning about forced induction.

JAX04

iTrader: (17)

search

https://ls1tech.com/forums/forced-in...urbo-saga.html

fstr n u

Thanks for the link. Haven't read it yet, but will as i've got some days off starting later today

robert miller

I agree also put the meth to it D/shot of it...

fstr n u

I"m trying to sort out now whether a 9.0 or 9.5 to 1 setup is better. Any suggestions>

Adam86

iTrader: (10)

Well with boost I've always heard the lower the better. Guess I can't think of any good reason to not go 9:1
Not sure how much extra boost you would be able to push with a .5 point drop in compression, but I would think that it would make any level that much safer.

Adam86

iTrader: (10)

Double...

sbcgenII

iTrader: (1)

tpunk

iTrader: (8)

CR really depends on your goals. No need to lower too much if you aren't going to put much boost on the car. Stock LS1's are fine with 5-8lbs and sometimes more. I'd be worried more with valve float than anything. The stock LS6 cam is actually a rather nice option for turbo cars and will save some money. Every high HP rear mount car has found that stock manis and wrapping the exhaust from the manifolds back is the way to go. The LT's are the biggest problem problem though. Also what are you using in the way of scavange pump? The stock pump from STS is garbage. You will also want to ditch the speed adjustment system for the pump. The oil return to the oil cap is also questionable at best. You will want to come up with a better PCV system than what STS sends as well. Nothing else comes to mind right off. I'm in the middle of getting the last couple peices for my setup right now but I've researched the crap out of it

XtremeDime

iTrader: (16)

I guess Ill be the first to ask....why did your #7 go out? What PSI were you running?

fstr n u

8-10 psi, the piston went completely caput at part throttle at around 3500rpm, before i even hit full throttle. Mind you, my car was dynoed as making 413hp at the wheels prior to this build, so hard to say how much power i made at the time of the "injury".

Schantin

iTrader: (6)

My $0.02. As mentioned above, 6.0 heads would be the way to go. C/R around 9.5 should be no problem with forged internals.... and will help a bit on low end torque before the boost kicks in.

You have a couple things hurting you. 3.90 gears are too much. 3.23's would be better to load the engine and build boost faster. Stock manifolds will also retain heat much better than LT's and will build boost much faster. Wrapping the I-pipe helps too.

If rebuilding, swap the oil cap return to an AN fitting in the pan or timing chain cover. Much more reliable. A vented catch can (ditching the STS PCV bypass is also a better setup. Ditching the stock STS bilge pump for a MOCAL return pump is HIGHLY recommended.

I'd also run a 2-bar SD tune on it with 60lb injectors and a high-volume pump. Conservative tuning and not getting greedy on timing is how to make the engine live happily at 10-12PSI.

I attached a thread I made concerning the oil pump for your reference too.

Good luck. Your goal is definetaly obtainable.

https://ls1tech.com/forums/forced-in...ust-pipes.html

r572cobra

forged ,383,rear mount turbo,11 to 1 compression,what do I need to change to run E85.

JoshuaGrooms83

iTrader: (2)

thought id revive another old thread to get some information flowing again.
so how goes the car these days?