GrandmasterCow

iTrader: (5)

HEy, I've been building my turbo kit now and I was curious at what my CR might be so i can figure out how much boost i can run.

6.0L 317 Heads
2003 MLS 5-layer metal head gaskets
LS6 Manifold
85MM TB
Diamond Pro-Select Ring Sets (1.5mm x 1.5mm x 3mm)
Eagle Standard Weight “ESP” H-Beam Connecting Rods (6.125")
LS2 Timing Chain
Diamond Racing Street/Strip Flat Top Pistons (Bore 3.905/Stroke)

67Firebird455

iTrader: (27)

You'll be looking at about 9.3:1 with those 2cc dish pistons, 3.905 bore with 3.622 stroke. Should be awesome for boost!

67Firebird455

iTrader: (27)

Same compression the ol 408's gonna have in the 67! You must be doing something right then buddy!

67Firebird455

iTrader: (27)

If running a 0 deck and .042 gasket instead of .055 and .008 deck, bumps it up to 9.7:1.

hellbents10

iTrader: (10)

Depends on the setup, and the cam. Need more info. input...input...input. hahaha

GrandmasterCow

iTrader: (5)

haha stock 98 camshaft. I'm not sure what the 5-layer MLS metal head gaskets compress too.

I bought the PTK hotside and I've built everything else. All goes on today and Friday (tomorrow for turkey day going to be booz'n it up and eatin' lots of turkey)

Also, how much boost can i safely run when i first get this setup together? I am planning on runnin a meth kit, but I'm probably going to keep low boost and work out kinks then get the meth and see how things go.

67Firebird455

iTrader: (27)

2 bar will be just fine on that motor, shifting below 7 grand. Enough power to definitely hurt yourself man.

CALL911

iTrader: (17)

9.7:1 should be good for mid to low teens in the boost. You probably don't want to go high teens in the boost though.

GrandmasterCow

iTrader: (5)

Thanks, it's all going through a stage 4 trans.

what would the biggest bottleneck for boost be? my piston choice? this originally was a n/a motor but i changed plans and went turbo instead, thats why i have those pistons. now i saw online a 2bar MAP sensor, should i go with this sensor? also, i've done some research about the MAF vs SD option and i think i'm going to keep MAF for now.

CALL911

iTrader: (17)

The CR will limit you the most honestly. Thats a decent CR for boost, but if you wanted high teens to 20+#'s of boost you should have setup for a lower CR like 8.5:1 or so. If your motor is setup right, you could easily have more power than you know what to do with without going crazy high in the boost (like 18+#'s). 2 bar MAP sensor will help make things easier for a good safe tune, and keeping your MAF will be fine I think.

My old LT1 is still using a MAF, and only the 1 bar MAP sensor the car comes with from the factory, and I was still able to have a good safe tune at 15#'s of boost (8.8:1 CR) on the stock PCM, with pump gas and still made 614 RWHP. The LSX cars are MUCH easier both to tune, and make power with.

67Firebird455

iTrader: (27)

Agree, compression is gonna kill you. You'd be able to run more boost without running ridiculous fuel on top of meth. I'd be happy even at 9.7 because NA it's going to run slightly better than an 8.5 motor. Being able to run 14.7psi (2bar) will knock the **** out of you either way. It'll stay together... run it.

Websy21

iTrader: (34)

Its all preferance, my 408 is being built with some 317 heads and 8.5 cr for my turbo so I can run shitty 91 octane and no meth while being able to run more boost. I do have a meth kit and while most likely run it when I crank it all the way up for the track. Good luck

CALL911

iTrader: (17)

Thats pretty much the rundown of things. Run a lower CR say 8.5:1 and you can safely run high amounts of boost, and will need less octane or need of methanol to keep you safe. The downside is the lower the CR, the lower the NA power of the car, so it might be more of a turd down low until the boost kicks in. Personally I think this can be a good thing, as you won't be really a turd, and in that time frame you'll have traction until you build the RPM's and MPH to the point at which the *** load of boost kicks in and then you are gone like no-ones buisness.

The higher the CR, the more NA power, but the less boost you can run safely. Higher octane is needed, and or methanol injection, but you still will be limited to doing things safely.

Optimally, find the target boost amount you are looking for, and then have your motor/CR setup for it. I knew I would be somewhere in the 13-17#'s of boost range in my car, so we made a good safe CR of 8.8:1. This would probably support 22#'s of boost safely, but I wanted to be on the safe side. I still need 93 octane, and methanol injection, but the power doesn't come on until half way up the power band, and then I have good traction and it works out just how I want it. This is what I reccomend.

Here's a couple vids showing me run my car with cold Nitto DR's in 1st gear against a few other guys. This shows I do indeed hook up awesome in 1st gear even with 614 RWHP.

Click here to see Video

Click here to see Video

Click here to see Video

Websy21

iTrader: (34)

Yes, I totally agree and that was another reason I did it too. I'll have to wait to see the vids when I get at home, the pc at work sucks.