prowan

I need help understanding where the 10.1:1 compression ratio comes from with the following information: 3.898" Bore , 3.622" Stroke, 66.67cc chamber volume. I'm using the equation: CR = ((pi/4)*bore^2*stroke)/Vc + 1 .... where Vc = chamber volume. Anyway the CR I calculate is = ((pi/4)*3.898^2*3.622)/4.0685 + 1 = 11.624. Is the 10.1:1 come from 'Dynamic Compression Ratio' that has to do with the delayed closing of the intake valve? HELP ME!! I'm Confused!! Thanks in advance!

SOMbitch

iTrader: (8)

No it is SCR. try this calculator>>>> http://www.csgnetwork.com/compcalc.html HG thickness is .054 and deck clearance is +.007.

This is in the ballpark and gives me 10.109950593436714 for a stock LS1.

prowan

THANKS A BUNCH!! Actually after I wrote that big spill, I back calculated using 10.1 CR and calculated for a head gasket and it came up with 0.057" which makes sense. Thanks for the link and the info. I may have to make a new thread, but does anyone know the stock CAM advance? The info I found only specifies duration and LCA, but no info on if it's advanced or 'straight up'.

DSkyles

iTrader: (1)

Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') What is it for a stock LS1 piston?

BriancWS6

iTrader: (18)

Stock LS1 pistons are flat tops with no valve reliefs.

bww3588

iTrader: (49)

deck clearence is -.007. they are out of the hole. not in.

sinful7

iTrader: (1)

it shows that the 63cc patriot stage 3 5.3l heads give 10.5:1 compression, i thought it was 11:1 compression??

SOMbitch

iTrader: (8)

Off the top of my head a 63cc chamber will give approximately 10.7-1 with a GM MLS. gasket. That is my setup right now. A stock 64cc 243 head will yield 10.5-1

Jeff Smith

iTrader: (44)

Thanks!! Good information..