fastassls1maro

iTrader: (22)

ive been plugging some numbers into some calculators but i dont think im coming up with the right numbers. could someone please double check?
thanks

LS1 block bored to 3.905
Mahle 3.905 pistons 16cc dish 1.314compression height
Compstar 6.125 rods
GM MLS headgasket 3.910 (.051" thickness?)
Stock 241 heads (66.67cc's?)
Deck height 9.235-245"

I came up with 8.923 static compression, does that sound right?
I plan on running this on motor for the first couple thousand miles and then eventually going to boost later on. It may see some 100shot hits as well after break in period

Any suggestions to what i should do if it is 8.923 CR, i imagine it will be pretty sluggish on just motor? I also plan on using the MS3 cam package from Texas Speed, along with a professional products 85mm intake and throttle body. car has full boltons

mark21742

Id look at flat tops with 8cc valve reliefs instead of the 16cc dish pistons and a .040" gasket. this will give you tighter quench and make it less prone to detonation...are you doing another cam swap when you boost it or leaving the ms3 in it?

Samer

With that low compression, you should NOT get the MS3 because it will be a disaster to drive the car.

The biggest cam I would go for in your case, would be this :

http://www.compcams.com/Company/CC/c...csid=1440&sb=0

Even by milling your heads to 59cc and going for a thinner head gasket, your compression will still be at 9.5:1

fastassls1maro

iTrader: (22)

well i do plan on milling my heads, and i was also planning on running a thinner head gasket as well. so if i do that it will put me in the 9.0-9.5:1 ratio, would that be more driver friendly till it sees boost? Would the MS3 cam work well with that CR?
Id rather not have to change pistons this late in the game as i already had my rotating assembly balanced. I did not however install the pistons in the block yet.

mark21742

You will want a cam with a very early intake closing point to try and hold as much volume in the cylinder as possible....since your planning on FI, is look at something like a custom grind around 224/230 .595/595 115-116 lsa.

If can, get your heads ported, this will drop your boost psi, but not heat the intake air as much and flow a lot better under boost do you can make more power with less boost.

With the compression your going for it will be sluggish (comparatively) before you boost it, but once boosted you should love it

Firehawk441

iTrader: (41)

How are you calculating the static compression without knowing the exact deckheight of the block? You listed 9.235-9.245. What is the exact measurement? You're talking about milling heads and gasket thickness, but you don't have the very 1st measurement you need to start with. You also need to measure weather the piston is at "0" deck or in/out of bore. Then you will be able to determine quench and the desired cc of the chamber...Best of luck.