High Compresion on Pump Gas?
09-04-2008, 09:17 PM
#1
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High Compresion on Pump Gas? How high can you take the compression and still run 91/92 octane in a LS1?
I've heard some people say 11.5:1 is scary and I've heard some say 12:1 is the MAX so discuss.
Thanks
-Russ
I've heard some people say 11.5:1 is scary and I've heard some say 12:1 is the MAX so discuss.
Thanks
-Russ
09-04-2008, 09:45 PM
#3
Patrick G did a good write up on how to get 500rwhp out of a stock cube motor. He has a section in there about compression ratios and the like. might be worth checking out. heres a link.. https://ls1tech.com/forums/generation-iii-internal-engine/732392-recipe-500-rwhp-heads-cam.html
09-05-2008, 09:02 AM
#4
Your going to find very different answers on this from who-ever you talk to.
When we build an engine for a customer we don't like them to be on the ragged edge. You don't control the quality of your gas with pump gas. SO why take chances? Most guys on here run as high as comp as they can because they are running to big of a cam and are trying to make up for the loss of low end tq with bumping the comp to the edge of detonation. The car isn't faster if its in the low octane table.. which is what happens when you go into knock retard. 11:1 should be your max but I know there are some who will say 11.5 and 12:1... but for what? an extra 3 hp? Not worth the risk for 99% of the cars on this board IMO.
When we build an engine for a customer we don't like them to be on the ragged edge. You don't control the quality of your gas with pump gas. SO why take chances? Most guys on here run as high as comp as they can because they are running to big of a cam and are trying to make up for the loss of low end tq with bumping the comp to the edge of detonation. The car isn't faster if its in the low octane table.. which is what happens when you go into knock retard. 11:1 should be your max but I know there are some who will say 11.5 and 12:1... but for what? an extra 3 hp? Not worth the risk for 99% of the cars on this board IMO.
09-05-2008, 09:19 AM
#5
Russ it's really hard to answer that question. It depends on a lot of other things. The tune, the cam, the altitude, the gas, etc....
To kind of answer your question, we ship 11:1 compression setups all the time that run on 90 octane without any issues. A compression jump from 11:1 to 11.5 compression should make about 8rwhp gains. While it's not a lot, that's more than the difference between most quality cylinder heads we engine dyno tested!
We have many different proven packages that can help you to get the power goals your looking to reach. Give us some more info on what your doing & I bet we can help customize your package to make the best power possible.
To kind of answer your question, we ship 11:1 compression setups all the time that run on 90 octane without any issues. A compression jump from 11:1 to 11.5 compression should make about 8rwhp gains. While it's not a lot, that's more than the difference between most quality cylinder heads we engine dyno tested!
We have many different proven packages that can help you to get the power goals your looking to reach. Give us some more info on what your doing & I bet we can help customize your package to make the best power possible.
__________________
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
