Light84vette

Could it be done? Are there pistons or heads out there that can bring the compression down to 8.5 to 1 or at least 9 to 1? If there is how much do they cost? Has anyone else made 700+HP from a stock CID or 382 stroker on boost? NO N20, BOOST, either turbos or Supercharger <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />

wicked 98z

Rob Raymer's '98 Single Turbo Z28
Dynoed @ 707 Rear Wheel HP & 730 Rear Wheel TQ
Best 1/4 mile: 9.94 @ 136.37 w/1.51 60ft
http://www.ls1motorsports.com/Project-Camaro.asp

y2khawk

iTrader: (5)

Mine is 348 cu in
15 psi
~8.75:1 CR

info in sig

MastaAce98

iTrader: (1)

I was curious about the guys that are running 10-15lbs of boost... are you guys studding the block? If not, what head bolts are you using, and what gaskets?

On the pistons, you can get pretty much anything you want directly from JE, SRP, Diamond, or any of those manufacturers of pistons. So, if you wanted an 8.5:1 or 9.0:1 motor, you'd have to start with the pistons. Just take into account the deck height of the block as well as if you milled the heads any or not.

I know of a guy that has a 383 stroker (stock bore) with the Vortech Kit + Aftercooler, but he's only seeing about 6lbs of boost on his, and he had a custom pulley made for the blower. I'm not really sure.

Anyway.... to answer your question on cost, I want to say they're about $700 for whatever kind of piston you want.

Light84vette

I know from other cars that once you get it to 8.5 you could run a pretty high amount of boost. Anyway, I would have to changeout the rods, and the crank also. But Isnt the stock LS1 heads speced at 10.5 to 1 compression? And if I get heads/Cam which says it could bring it to 445HP, does that increase to compression ratio, or just have better flowing heads?

Also when you run 15psi boost or more, would the stock ECM be ablt to handle the increase in boost and alter the spark curve and the Fuel injection pulsation and all that? OR would I have to upgrade to a FAST or accel DFI system?

AP-Engineering

I have a blower / turbo piston in stock for the LS1 engines. #11503, this piston will handle up to 20 psi. Let me know if I can do anything for you.

Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free

J-Rod

LPE has been doing fairly high boost on some of their cars. The big thing is to convert to an earlier style adjustable fuel pressure setup, rahter than the fixed one that is pump based.

As for the ECM, passing the max airflow of the mass-air and going over the RPM limit of the ECM will be your only issues. If you do either you will have to tune for static conditions which the ECM will go to. At that point it makes a lot of sense to go to an aftermarket setup.

Pro Stock John

iTrader: (34)

I am building a 346 + .005 motor with Diamond pistons and 6.0 heads shooting for a target compression ratio of 9.1:1. This is with 70/71cc heads that have been milled to 69cc's FYI.

Note that Harlan's numbers were on a Eddy current dyno, a load-based dyno... (not to swing from his nuts)but his numbers are more like 740-750rwhp on a Dynojet 248 which is what 95% of us use.

I am using ARP main studs and I will be using head studs as well.

Proper fueling will be the key to making combos like this work.

TEA Brent

I can put a cnc'd 77cc chamber in your heads to help you drop your compression. Let me know if I can help you out.

Light84vette

Where could I get 6.0 Heads from? Do they flow just as much as the aftermarket SLP heads? Also I couldnt find any link of LS1 pistons that are that low in compression, the only ones I found go to 10.1 as the lowest.

So are you guys saying that the F-body ECM cant handle the change in manifold pressure and alter the spark and Injection curves? So does this mean I would have to go to an aftermarket Engine managment system?

Also If I go with a 4 inch crank and go to 382CID, Would it have a slight affect on compression? And where could I get them from? I heard of them but I just dont know where everyones getting them from.

Plus how much power can the T-56 Transmission take? It on a 2002 TransAm right now And I'd like to make more power with it, but I would like to know how much can they take? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

Ling_650vette

iTrader: (1)

Check out GMHTP this issue, got a complete Gen III head rundown. And you can find LQ4 heads which are Chevy/GMC 6.0 heads which the comp ratio's 9.4:1 @ a junkyard probably w/ a wrecked truck.

strokedls1

iTrader: (1)

Those 6.0L heads would be key to dropping the compression ratio. People that get a 346 to put down 445hp are uping the compression ratio. Running high boost means replacing everything on the engine. Heads, cam, block, timing chain, head gaskets, pistons, rods, crank....ect. It can add up quick.

Light84vette

What GMHTP? Also would those heads flow just as much as the SLP heads/cam package heads?

DetroitZ

I wouldn't put much stock in SLPs heads. I saw a SS trap 115 with their heads/cam and a 75 shot. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> . Give TEA (a sponsor) a call for a set of stage 1 truck heads

Light84vette

Could you guys please help me out and tell me what the heck these abriviations are? I dont know what GMHTP stands for either TEA? COuld you give me a link and maybe a name of the company that sells them? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

DetroitZ

GMHTP is a GM high performance magazine. TEA is
Total Engine Airflow (270)782-6397 They are a sponsor of this site. Above is a post from them.

Ling_650vette

iTrader: (1)

yeah, GM High Tech Performance magazine. Comes out every other month, really good mag, imo.

And the LS1s comp is 10.1, the LS6s is 10.5. LQ4 is 9.5 and the LQ9 is 10.0. LQ4 and LQ9 heads are similar to LS6s w/ the D shaped ports, but its the compression droppage that makes them ideal for forced induction applications. Only probelm w/ some of them are, the earlier ones are cast iron, which adds weight. But to some people, its worth it. Hope this helps

Ling_650vette

iTrader: (1)

and i personally, dont trust much of what SLP offers as far as "aftermarket" accessories. I'd much rather hit up LPE, ARE, MTI, TEA or someone like that for head work. I dont put much stock in some of SLPs stuff...(funny, being i want an SS lol)

Just look through the sponsers to the right. Lots of options out there, and it really comes down to preferance, and what your wallet says. You're not limited when it comes to LS1 aftermarket, plenty of companies offer heads, cams, exhaust and complete performance packages. Check through the sponsers, and i'll guarantee you, you'll find something you need

Light84vette

Thanks for your help, I will check into it. But I have a question, if you run say 15psi Boost on a prepared LS1, would the stock ECM be able to handle it? I mean adapt to the new boost and then alter the spark and fuel curve? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

Ling_650vette

iTrader: (1)

I dont think so. I dont think it could quite account for the increase w/ the blower. It may be able to tweek itself a little bit, but i doubt it'd be able to optomize it. But, there are companies out there you can go to that offer computer stuff.

I know Ed Wright seems to be pretty popular. And with Magnacharger, Superchips has a setup specifically for them, but you're in the right place to be asking...maybe someone w/ a lil more experience can help