Pump gas

[stlmikie]

What is the highest compression you can safely run with pump gas. Say 93 octane?

 

[V]

Can't give a exact answer but it does depend on engine timing and camshaft selection. A short duration cam will build higher cylinder pressures where a long duration cam will bleed off some of the cylinder pressure. I think there are several guys on here running 10.5-1 and Marv may be running a little more than that.

V

 

[chacha]

Most I've heard is to stay under 11 to 1 if you're not running racing fuel -- that damn detonation thing.

 

[stlmikie]

I am rinning 10.5 now. I found a guy that will mill the heads for a a great price but i wat to take it to the limit. I need to know what the limit is though.

 

[alhall88]

camshaft duration plays a huge role in this, I'm running 10.8 as a few others are here. Timing set at aggressive curve @28 BTDC and so far no pinging on my end with 93/94 octane. But thats also not to say that it doesn't run great with the good high end petrol

 

[V]

I am rinning 10.5 now. I found a guy that will mill the heads for a a great price but i wat to take it to the limit. I need to know what the limit is though.

You're only limited by your wallet, Sunoco 100

 

[stlmikie]

Thanks guys!

 

[WRM66]

Can you run race fuel (like VP105) in a stock motor and if so, would it make much of a difference? My buddy has an 04 ridgeback with a 107in. stock motor.......He make a comment about getting some race fuel to try and help his performance against our 117in. dogs in the group we ride with. None of us knew if it would run better or not, so i told him I would ask the experts on this sight......what's your input on this? Also, how would it perform in my Dog.....I ride an 06 mastiff, 117in. with a 659 cam in it.....

 

[stlmikie]

I can't see that it would increase the hp. Some of the guys claim that it runs smoother but I can't see an increase.

 

[sh8kr]

The real truth is if you don't have the compression and cam
along with proper timing you will hurt your performance if used straight. Simply stated the ignition can set to fire when the Piston is closer to the spark plug.