I am planning on running 12-20 lbs of boost, and running 9.1:1 compression. I am planning on using pump gas. Someone told me i should lower the compression. I was wondering what the advantages of each. More compression and less boost or more boost less compression. Which is better?? What is a good Compression Ratio?

For 12lbs?
For 15lbs?
For 20lbs?
(all on pump gas)

 

I'm only sure of the very basics. More boost and less compression makes more HP than less boost and more compression (obviously within reasonable situations)
I've been told you just gotta be careful how low of compression you run or you could end up with no bottom end power. I'm not gonna try and guess what CR ratio with how much boost as I'm just not the knowledgable...yet...I'm learning .

Stephen

 

Like stephen said, there will be more power with more boost less compression than the other way around.

I know it can be done, but I wouldn't run 20psi with pump gas, not even with lower compression. You will have to pull alot more timing out of the motor than you would with race gas.

9.1 is fine. I'm in the process of a 383 9:1 turbo motor with a max of 23-24psi, but im not even thinking about pump gas.

Are you planning on a turbo or blower? If its a turbo then just use race gas at high boost and open up the waste gate for pump gas. My 2 cents

 

Very well said . A buddy of mine has a blown cobra, he see's A LOT of boost. When he runs around on the street (rarely) and wants to run pump gas he has a chip that pulls a lot of timing. He also has a chip for "Kill" which is a degree of timing put in and on this setting he is running 116 octane.

 

If you want to email me with your compression and boost, bore and stroke, and VE if you have it - I can give you boosted compression numbers and required octane numbers.

Thanks, Rick @ STS
STSTurbos@hotmail.com