What kind of fuel are most of you running??The higher the octane the faster the combustion will be and performance will be at it's best along with clearer engine!!and don't forget about better fuel millage.most utility type atv's were built to use a lower octane level I think!!REG-87%....midgrade-89%.....super-91% It will be intresting to see the input from all the riders out there!!!!!

 

I am a cert mechanic and can tell you that with out a doubt using higher octane fuel is a waste of money. Just because you put a higher octane fuel does not mean it will run better. In fact in most cases it will run worse or no change at all. Higher octane burns at a higher temperature and only works as it is supposed to in higher compression engines. A 12:1 compression will require a higher octane. If you use a low octane fuel in a higher compression motor it will melt. Most likely you will not notice any difference between 87-91,92,93 octane in a 4 stroke motor. 2 strokes run at a higher compression and to help with pre detonation it is recommended to use 91-93 octane but not the case in 4 strokes. A lower octane will combust quicker than a higher octane. 2 strokes you will get pre detonation with the lower octane fuels because it burns hotter but it will not burn all the fuel in the cylinder so you get the pre detonation.

 

Yeah, what he said..[img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-cool.gif[/img]

 

You want to run the lowest octane you can before you get pre detonation … the octane number is it's resistance to detonation, the higher the number the better resistance to detonation. If your engine isn’t designed for high octane fuel you will get less power out of it.

 

Higher octane burns at a higher temperature lower octane fuels because it burns hotter
Confused

 

what ever the min. requirerments are on your own machine is what i would gowith unless you have raised your compression. cant go wrong w/ what the factory recommends.

 

Factory recommends regular..87 octane..now with my motor since I've done work and my compression ratio is roughly 11.5:1 almost 12:1 I run VP 105 in mine because it has the compression for it. Also my timing is advanced 5 degrees. But for stock motor run 87!

 

Now I read the above, but my Polaris dealer said different. Confused. I have a Polaris Outlaw, the owners manual stated the "minium" requirement is 87 Octane. My dealer states for a high performance quad the "recommended" is 91 Octane. How do I know what's correct? Burning at a high temperature is not necessarily better.
I used to ride Polaris 500 Sportsman and it ran great on 87 Octane, but I also driven older model sports cars that knocked on lower on 87 Octane.

 

Your dealer is misinformed. If the manual says 87 minium, rest assured it will not ping on 87.
Cars of old had high compression. Some, like the 426 wedge had 13 to 1 from the factory. My 340 does not like anything less than 92; and even at that I have to play with the timming.

 

Doctorturbo,
Thank you. I believe you are correct. I think the Dealer is still in old high performance 2 stroke vs. newer high performance 4 stroke mode. Simple test, I'll add 87 Octane next fill up. Another question. Does extreme temperatures of fuel affect performance, i.e. 0 degrees F. or 100 degrees F?
LW.