If all other things are equal, the higher octane will give slightly LESS power due to the higher flash point, and it being slightly harder to ingnite. Your Z250 should run fine on 87 octane. Anything over 89 is just a waste of money(for the motor you have)

 

The increased performance from Ultimate 4 (octane=92.2, not much more than pump gas) is because it runs LEAN! If you are jetted a little rich, that might be OK, but if your jetting is spot-on, going leaner wouldn't be a good thing.

 

MBrooks420
Exactly

 

I ran a mix of about 3/4 tank 92 octane and 1/4 tank 110 octane in my 96 mojave, and I DID notice a difference.
I dont know the compression ratio of the Z250, but the mojave is 11:1. I was told that by running higher octane,
the motor would run cooler, therefore more efficiently. That is where you see the difference. It probably doesnt
give you more power, it just doesnt lose power.

My 2 cents.

P.S. PACKERS are in the playoffs!!! (not that this has anything to do with ATV's, just couldnt help it!!)[img]i/expressions/face-icon-small-smile.gif[/img]

 

Thanks a ton for the info you guys!
Yea did you see that catch the cardinals made to beat the vikings. WOW

 

I run 115 octane race fuel (VP C-15). I only run this octane because of the compression I am running.....