Hey guys I have a 2000 TrailBlazer and I was just wondering if anybody has any ideas on what octane of gas is best for 2 strokes or does it really matter???

 

MEDSKER,

The manual says to use premium, but at a compression ratio of 6.1:1 you'd just be wasting your money. At that low of compression ratio you could easily run 87 octane forever without problems.

 

I agree with Mike, I have been running 87 in my Y2k Blazer since I got it in November. No problems.

 

I had a friend who put 93 Octane into his Honda Foreman and it started running rough and then just stopped running and wouldn't restart. After messing around with it for a few mins, we decided to drain the 93 out and put in some 87. As soon as we put the 87 in it, it fired right up and didn't have anymore problems. Never saw anything like that! I ran some 93 in my Scrambler and had no problems at all, but it didn't seem to run any different than when I run 87 in it. Anyone else had trouble running higher octane in their machine?
Later,

 

Mike, you hit it bang on. If the compression ratio is not high the 93 octane is a waste of money.

I can't believe how many people put high octane fuel in their passenger cars and swear it won't run right if they don't. Case in point is a friends girlfriend who pounds the 93 octane to her Crown Vic. If you have purchased gas in eastern Canada lately you would know this is a $70 fillup!

DJ

 

96 Cobra,

Sometimes it really makes me chuckle how people associate high octane with high performance. I'd be willing to bet that your friend with the Honda was running it on a cold day. It seems that with high octane, some vehicles that are particularlly cold blooded, don't want to run as well or at all if they start because of the higher octane.

Octane is nothing more than a way of getting gas NOT to burn prematurely in HIGH compression engines that have compression ratios of 12:1 or better. Higher octane can even hinder performance in certain engines.

 

If your engine does not have any pinging [spark knock]than you are wasting your money with higher octane fuel.Only go to higher octane when spark knock is appearant.===BILL

 

I was always told that a higher octane fuel was used in situations where the engine was run in higher altitude. My pilot friends use 100 octane low lead fuel in their craft, as it burns better in lower oxygen at higher altitude, thus the reason they have to turbocharge pressurized high altitude aircraft running gas powered engines. I have used high octane fuel in my SP and never noticed a difference, and I live around 1300 feet, so a higher octane fuel wouldn't really make a difference anyways. I'm paying around 70 cents a litre, about 1.80 a gallon US for fuel for regular unleaded, I can't see spending the extra bucks for high octane gasoline.

 

Compression ratios in 2 strokes can be misleading . The 6.1 :1 is what is called a "corrected" compression ratio. It is actually higher than that when calculated full stroke . Aftermarket heads are calculated full stroke , unlike the way Polaris calculates theirs .


Anyway , I ran 87 octane in my T-Blazer with no trouble , but , in testing we noticed after a few test runs a T-blazer will begin to heat and lose a marked amount of performance . If I had easy access premium fuel (90 plus octane) I would use it in my T- blazer . It may keep things a bit cooler .

 

I have always been told that premium fuel is good insurance against detonation which is premature ignition of the fuel charge by high heat. This can either be caused by high compression or insufficient cooling. With air cooled 2-strokes this can be a problem in low speed situations. High compression is not a problem in polaris engines. Personally I run regular fuel but I dont run the engine that hard so I dont worry about it.