[GMR-PERFORMANCE]

I would say that you do not have too much for pump gas,.. static does not mean anything at all until the cam is factored into the formula. I am running 11.1 with the Howard's cam that is so close to the comp 294 ( one step under this cam a 300) That cam is going to hemorrhage CCP at low & mid RPM levels. I don't know where the idea came about that you cannot run higher compression on the pump gas. We build air cooled HD engines and run them well above that.. It is all based on the cam timing.. Look at the dynamic compression not the static.

I have 11.3 in my 900 lbs touring bike it runs on 91 octane fuel in 110+ temps here in AZ.

I don't have the intake close point at 50 for that cam but based on my own cam and 11.1 comp ( mine closes before that 300 does) my dynamic is 8.8.1 that WILL run on 91 octane fuel. If you cannot tune a engine well thats another story no blame on the set up though.

His will be at the " so called" 8.5.1 or under level. No idea where that 8.5.1 limit came from for pump gas.. but that must be for the no talent tune deal.

I get a bit testy when it comes to compression and set ups. There is no set in stone number. Static is just that a simple formula for cylinder volume. Add the cam and then you have something as a base line. Even that is only a base line type figure, as there is a ton more going on with a cam lobe then a few figures that get published. We own several custom cam grinds that I designed. And after you see what is really going on with a cam and how it works its a real eye opener..


Update I played around with another of my programs. here is his set up with that cam.. It was lower than I had thought.. In fact he could bump the comp ratio a bit and still get by on 91 pump gas at his level his is all in the safe zone.. : ) I ran it for 0 feet if you have another target for elevation let me know , but it will only lower the number.

Static compression ratio of 11.1:1.
Effective stroke is 2.61 inches.
dynamic compression ratio is 8.03:1 .
dynamic cranking pressure is 159.75 PSI.
dynamic boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0 PSI is 8.03 :1.
V/P (Volume to Pressure Index) is 128