please confirm DCR calculation of LS2 combo
01-21-2014, 11:30 AM
#1
please confirm DCR calculation of LS2 combo i got a used engine, used heads and used cam
did my homework, but just want to confirm my findings because i dont do these calculations very often. I'm about to send my carb off for a rebuild, and i need to know if i should have it converted to e85 due to my compression and DCR. anyways, here is the combo, and if you have any questions i can answer them.
Engine:
stock bottom LS2
Stock head gasket
61 cc combustion chambers (tfs 225 heads)
i figure after flycutting the intake side of the piston, i'm around 11.7:1 compression.
cam:
my calculations came out to 8.95ish DCR which is well over the "limit" of 93 octane according to internet racers who claim 8.7 or so is the limit.
can someone check my math? SC and DCR...once someone confirms my math, my next question is should i step up to e85 on this build. i plan to run a 200-250 shot through this engine too.
did my homework, but just want to confirm my findings because i dont do these calculations very often. I'm about to send my carb off for a rebuild, and i need to know if i should have it converted to e85 due to my compression and DCR. anyways, here is the combo, and if you have any questions i can answer them.
Engine:
stock bottom LS2
Stock head gasket
61 cc combustion chambers (tfs 225 heads)
i figure after flycutting the intake side of the piston, i'm around 11.7:1 compression.
cam:
my calculations came out to 8.95ish DCR which is well over the "limit" of 93 octane according to internet racers who claim 8.7 or so is the limit.
can someone check my math? SC and DCR...once someone confirms my math, my next question is should i step up to e85 on this build. i plan to run a 200-250 shot through this engine too.
Last edited by TXsilverado; 01-23-2014 at 10:26 AM.
01-22-2014, 08:06 PM
#2
Am I reading right, it's a 110+4 cam?
Using that I get just a tad over 9.0 DCR.
I'm running 8.8x DCR right now with 93 octane and have not had any issues with knock, even with timing advanced a few degrees throughout the table. Although I have better quench, so that helps. With loose quench like your setup, I would not go ~9 DCR.
Using that I get just a tad over 9.0 DCR.
I'm running 8.8x DCR right now with 93 octane and have not had any issues with knock, even with timing advanced a few degrees throughout the table. Although I have better quench, so that helps. With loose quench like your setup, I would not go ~9 DCR.
