Hey guys

I recently tried STP's new octain boost fuel additive made from jet fuel in my sportsman 800 (after break-in period). I dumped about a shotglass full into my full tank of Unleaded Premium, shook the 4 wheeler to stir in the additive and started it up and immediately noticed a large powerbanned increase and a higher idle rev of about 60 more RPM's. I have no idea if this is good for the motor or not, but the bottle does state safe for all gas engines, so its probebly ok. If you want a large powerban power increase for 3 bucks, buy a bottle of this stuff, I'm impressed.

 

The only way your statement could be true would be if you were running too low octane to begin with. Running higher octane or gasoline additives will not boost power unless it wasnt running correctly to begin with.

 

That can't be true at all ... jet fuel is refined diesel, without any lubes added. The octain would be WAY higher than an gas engine could burn, even people that put jet fuel in their diesel engines have issues with fuel pumps and injectors. Jet fuel is made to burn at 700C, your engine is not running at 700C. Go look at the specs for an King Air C90 or F90 aircraft, it's a turbo prop running jet fuel.

 

well i dont know how it could happen like that then, it idles at about 1080RPM's when its 50 degrees out, and i was running premium, maybe i got hoaxed by thortons

 

You should try an lower octane fuel ... you want to run the lowest octane you can, before you get engine knocking ... higher octane fuel doesn't give you more power unless your are running a high compression engine. High octane fuel in an lower compression engine will not burn completly and end up giving you less power.

 

well the compression ratio is 10:1 which is basicly running medium grade fuel, so i figured why not just run premium. i see 10:1 as a pretty high ratio

 

Here's the general rules i follow...

1. 87 Octane fuel under 20 Deg F riding
2. 89 Octane fuel general riding
3. 92 Octane fuel + 100 Deg F riding


As the octane increases the head temp should lower (since higher octane fuel should make it run rich)

I like 89 octane fuel in my 500HO, it "seams" to have less engine noise.

[img]i/expressions/face-icon-small-smile.gif[/img]

 

well speaking of running it rich, i really dont have that problem since i have EFI and it auto compensates, but i'll try the different ranges of fuel to see, thanks for the tips

 

[img]i/expressions/face-icon-small-smile.gif[/img] OT: have you gotten your 800 muddy yet? How did it do?

 

i havent gotten it muddy yet as its been raining for the past week and ive only had a chance to put about a total of 30 miles on it. but so far it met my expectations but im yearning for more [img]i/expressions/face-icon-small-tongue.gif[/img] i wish Dyno-Jet would hurry up and make that damned power commander. I havent had any problems with it so far and im very impressed with it. my local dealer had a used Brute force that they just got that a guy picked up a XP with, so they brought out a 800 with only a 10th of an hour on it, they did a drag and this is how it went. keep in mind that the brute force was way past its break in period and had its full power, while the 800 is brand new outa the crate.

they hit the thumb switch and both of there front ends popped up and did wheelies for a few feet. the brute force was the first one to land and it crept forward of hte 800. the 800 then landed and shot off from the brute force and was ahead by about 4 quad lenghts, then they hit about 45 miles an hour and the brute force edged up on the 800 and look a 2 quad lead, then the 800 slowley crept up on the BF again as they neared about 60. the 800 ended up wining by about a foot and a half.

so imagine what ited be like if the 800 were broke in. all this was done on a paved flat, straight road