What will my compression ratio be?
Thread Starter
Pro
Joined: Oct 2009
Posts: 712
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From: Panama City Beach Florida
What will my compression ratio be?
Im building a forged 347 wth 6.125 rods, stock stroke, and -9cc inverted dome pistons. I will be using stock mls gaskets and 317 heads with the larger chambers than what came on my ls6.
What should my compression be? i calculated a hair under 9:1 but wanted to be sure
I will also be using the stock ls6 cam if that matters
What should my compression be? i calculated a hair under 9:1 but wanted to be sure
I will also be using the stock ls6 cam if that matters
Former Vendor
Joined: Apr 2006
Posts: 2,470
Likes: 2
From: Portland OR
St. Jude Donor '10-'11-'12
Former Vendor
Joined: Apr 2006
Posts: 2,470
Likes: 2
From: Portland OR
St. Jude Donor '10-'11-'12
the LS9 is thicker, and will drop it more... .053 IIRC 8.95, use a deeper dish piston. around a -14.5
-14.5 cc dish and .053 with 4.080 hg bore is 8.49
-14.5 cc dish and .053 with 4.080 hg bore is 8.49
Last edited by 99blancoss; Jun 3, 2010 at 12:56 PM. Reason: added info
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Tech Contributor
Joined: Sep 2005
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From: New Market AL
have you fully researched the ideal compression ratio for a boosted LS1? Most people are running 9 or 9.5 static compression for a boosted LS1. My 408 that I just built for twin turbow calculates right at 9.0, and Shawn from Virginia Speed said I am leaving some power on the table by not bumping it up to 9.5. These GenIII engines have very efficient combustion chambers, coupled with good quench pads. You have to think outside the box from the old SBC days.
Former Vendor
Joined: Apr 2006
Posts: 2,470
Likes: 2
From: Portland OR
St. Jude Donor '10-'11-'12
The flip side being if you stay conservative your generally safer with more boost. We've seen them from 8.6 - 10 all depending on a s/c or turbo and the customers personal taste