Compression experts inside please
Thread Starter
Drifting
Joined: Dec 2004
Posts: 1,937
Likes: 1
From: Tempe Az
Compression experts inside please
Friend and i are having a discussion about the most pump gas compression for an LS1. I say the highest you should go would be 11.5:1 on 93 octane and he says 12:1. What's the highest compression you can do with pump gas?
Cruising
Joined: Jun 2004
Posts: 12
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From: Bethel Park Pa
I gotta vote for 11.5. At 12 it is already a diesel. If it had a carb instead of FI it would not stop if you turned off the ignition. The preignition would destroy the pistons in short order.
Last edited by Redspark; Mar 8, 2006 at 04:54 PM. Reason: addition
Race Director
Joined: Dec 2004
Posts: 13,760
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From: Haymarket VA
It's not that simple. Your dynamic compression ratio is much more important than you static. Dynamic compression is controlled by valve/cam timing. A larger cam will need a higher static compression ratio in order to maximize it's benefits. The opposite is true for a smaller cam like stock.
Most people like to see a dynamic ratio of around 8.5:1 for 93 octane.
Now throw into the mix that you can get a higher compression engine to run fine by retarding the timing to eliminate knock and detonation but in the process once again you've done away with the benefits of the higher compression.
As I said, it's not that simple.
Most people like to see a dynamic ratio of around 8.5:1 for 93 octane.
Now throw into the mix that you can get a higher compression engine to run fine by retarding the timing to eliminate knock and detonation but in the process once again you've done away with the benefits of the higher compression.
As I said, it's not that simple.
Cruising
Joined: Jun 2004
Posts: 12
Likes: 0
From: Bethel Park Pa
Choosing between 11.5 and 12.1 is like choosing between death by firing squad or death by hanging. Either way you are not long for this world. But maybe you are building an engine to only last for a ¼ mi .Do not expect the computer knock sensors to help because the computer will be retarding the ignition which will have no effect since the problem will be preignition.
Last edited by Redspark; Mar 8, 2006 at 06:16 PM. Reason: error
