Compression Ratios
Thread Starter
On The Tree
Joined: Sep 2009
Posts: 197
Likes: 0
From: Huntsville, AL
Compression Ratios Hi. I'm trying to figure up a spreadsheet to calculate compression ratios.
I'm using this engine as an example just because it looked good:
http://texas-speed.com/shop/item.asp...d=827&catid=28
bore : 4.005
stroke : 4.1
deck height : 0.0015
Piston offset in cc : -11
gasket bore : 4.1
compressed gasket thickness : 0.038
Chamber Volume : 64
I had to guess at the deck height and gasket bore / thickness. I used this article to get my figures:
http://www.carcraft.com/techarticles...tio/index.html
I come up with a 14.75:1 compression ratio. Isn't that a bit high? Am I buggering something up somewhere? What did y'all get?
I'm using this engine as an example just because it looked good:
http://texas-speed.com/shop/item.asp...d=827&catid=28
bore : 4.005
stroke : 4.1
deck height : 0.0015
Piston offset in cc : -11
gasket bore : 4.1
compressed gasket thickness : 0.038
Chamber Volume : 64
I had to guess at the deck height and gasket bore / thickness. I used this article to get my figures:
http://www.carcraft.com/techarticles...tio/index.html
I come up with a 14.75:1 compression ratio. Isn't that a bit high? Am I buggering something up somewhere? What did y'all get?
I got 11.125 CR using the standard GM MLS gasket thickness of .051" or if you use Cometic .040" it'll be 11.41 CR. That's assuming deck height is the usual .01" and you use the preferred gasket diameter of 4.03".
This is the CR calculator I always use:
http://www.csgnetwork.com/compcalc.html
This is the CR calculator I always use:
http://www.csgnetwork.com/compcalc.html
Last edited by batboy; Feb 14, 2010 at 04:28 PM.
Need to do some looking into engine-specific deck heights and gasket thicknesses next time I think. 
