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Oct 20, 2008 | 07:06 AM

#41

No Juice

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From: Minnesota Corn Fields

Quote:

Originally Posted by DrkPhx

I like this one: http://www.rbracing-rsr.com/compstaticcalc.html

How come I get 10.4:1 using stock LS1 specs? Bore=3.905, stroke=3.622, deck=-.007, gasket=.052, cc=66.5

Oct 20, 2008 | 10:31 AM

#42

Haans249

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From: Fort Worth, TX

Quote:

Originally Posted by No Juice

How come I get 10.4:1 using stock LS1 specs? Bore=3.905, stroke=3.622, deck=-.007, gasket=.052, cc=66.5

Thats because you have your bore wrong...

Bore = 3.898, the 3.905 is a honed bore size.

Oh, and your deck height should be a positive .007, not negative. The negative is with the piston coming out the hole, but most LS1's are in the hole about .005-.008.

Last edited by Haans249; Oct 20, 2008 at 10:37 AM.

Oct 20, 2008 | 10:38 AM

#43

No Juice

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From: Minnesota Corn Fields

Quote:

Originally Posted by Haans249

Thats because you have your bore wrong...

Bore = 3.898, the 3.905 is a honed bore size.

Oh, and your deck height should be a positive .007, not negative.

good point, but that still only changes it from 10.43 to 10.4?

Oct 20, 2008 | 10:55 AM

#44

Haans249

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From: Fort Worth, TX

no it doesn't, it changes it from 10.43 to 10.07....

Oct 20, 2008 | 11:05 AM

#45

No Juice

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From: Minnesota Corn Fields

Quote:

Originally Posted by Haans249

Oh, I thought they were out of the hole?

Oct 21, 2008 | 12:37 AM

#46

Haans249

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From: Fort Worth, TX

Nope, LS1 pistons are in the hole. That's why a lot of people run 40thou gaskets, as its a safe and easy way to up the compression on a stock LS1 motor without having to deck the heads or block.

Adrian

Oct 21, 2008 | 02:03 AM

#47

WhiteRhino

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From: NV

Quote:

Originally Posted by Haans249

Almost every lsx i've seen or read about is out of the hole. With very few in the hole. Not sure why you say ls1's are in the hole. If you search "piston out of the hole" or "quench", tons of threads come up with piston out of the hole talks. Most people run thinner gaskets to get proper quench that i've read about. Added compression is a bonus as well.

I thought ls1's were around .007 out of the whole from the factory. That's why it's best to measure before swapping gaskets. So the piston doesn't smack the head.

Oct 21, 2008 | 10:12 AM

#48

Haans249

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From: Fort Worth, TX

Well, I must be mistaken then! Its been a while since I worked on a LS1 motor haha. Maybe the difference in the compression is the top-ring-down volume that isn't accounted for in that calculator.

My bad fellas.