Snowmobile World banner

1 - 2 of 2 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
I was once told by an engine builder you can run 9.8:1 compression ratio on 91 octane gasoline in a car. Will 8.35:1 ccr survive with 91 octane in a 2 stroke snowmobile? Let's hear what you all have to say.
 

·
Registered
Joined
·
476 Posts
Well, you see there are two C/Ratios in four strokes and in two stroke engines. They are Mechanical & Effective. The 9.8 to 1 on the car eng. would be a mech. C/R and that depends on the engines camshaft. If the intake valve closes early the 9.8 to 1 won't work. If the intake valve closes later no problem. The mech. C/R on stock two stroke eng's is around 12 to 1 and the eff. C/R is around 6.5 to 1. In two stroke eng's the C/R is almost always refered to as an eff. C/R. Now the 8.5 to 1 number leads me to belive you are talking about eff. C/R and if thats the case you had better be feeding that honey some hi octane fuel. That C/R would be for racing only!

Auggie
 
1 - 2 of 2 Posts
Top