compression ratio
Thread Starter
Staging Lane
Joined: Jan 2010
Posts: 67
Likes: 0
compression ratio Hey guys need some help planning my build and figuring out compression ratio. I'm going to rebuild my ls1 to a 383, 392, or 395 ci like texas speed offers. Im gonna run 799 heads (cheap) that I know bump comp up about .5. I know im gonna need dish of valve relief pistons but don't know how many negative cc to go. If possible I want to go low enough for a supercharger setup 9-9.5:1 im guessing. If not ill pass on the $7000 plus price tag for one. This is my first rebuild on a car engine so this is all kind of rocket science to me. Thanks for the help in advance.
11 Second Club
Joined: Mar 2012
Posts: 1,541
Likes: 15
From: South Florida
What's up man. Saw your other thread in the dyno section. This is a good calc for compression.
http://www.wallaceracing.com/cr_test2.php
http://www.wallaceracing.com/cr_test2.php
On The Tree
Joined: Dec 2011
Posts: 118
Likes: 0
From: Colorado Springs, CO
I know this is about to be even more like rocket science, but your static compression ratio will only get you so far. You also need to look at the cam you're using. You can always go with a slightly higher compression piston and have a larger intake duration on your cam. This will make it so the piston is higher in the cylinder when the intake valve closes, thus lowering the dynamic compression ratio of the motor. Also, if you want to have higher compression, running a higher octane fuel helps a lot. Especially getting into race fuel and running a water/methanol kit. These things can help reduce the risk of detonation and pre-ignition.
