Blownsilver
Active member
Anyone else running this compression? What fuel do you run, told pump gas at elevation and 110 down low. Whats your experience, 110 is so bloody expensive the way my cat goes thru fuel
Depends on the flame front relief area cut (squish), deck height, and actual engine model. Too often a head is cut, but the squish isn't machined back into it. Most any head builder will know their product - best to check with them. Example: I ran 13.5:1 @ 3500' on pump, but had .060" squish on a 05 Doo 800 HO. If I had only .040", I would have needed better fuel to sustain a decent WOT pull. Plug color and piston wash will tell you if you are lean, as well as the exhaust note. BTW, too "tight" of a pipe will also back up heat to the exhaust port and necessitate better fuel to survive.So in your opinion,would a 13.1 head run safely at sea level on 91 gas?
Thank-you for the reply. The reason I'm asking is because I have a 13.1 PAR head on my 11 pro 800 and am taking it to Ontario next week. I wont be able to mix any higher octane race gas other than the 1st tank of fuel when we leave on our sled trip. I am hoping to just be able to add octane boost to eliminate the potential DET issues. To the O.P. I hope you are not offended with this somewhat hi-jack of your thread.