What gas to run at elevation?

[buck50]

i know there have been several threads about this before, and one is going in general right now, but they seem to deal mostly with low elevation riding. we ride mostly golden and revy and have been putting premium into our sleds. is this necessary, or does regular work better? especially in the golden/revy areas where elevation is roughly 6000 to 9000 ft. any input would be greatly appreciated

 

[BigBlueEdge]

I'm certainly no expert, but what I've come to understand is that if your sled takes premium as the recommended fuel, then put whatever is being sold as premium at local gas stations into it. i.e., If you run premium 92 octane at low elevations, then buy premium from the pump up in the mountains, regardless of what octane it is. It will probably be a bit lower number at altitude. Don't worry about the specific numbers. This assumes you are jetted appropriately for the altitude you are running.

But if your sled doesn't need premium then don't run it. Using premium on an engine that isn't configured to make use of the higher octane (compression) will give you no added value.

Rob

 

[SnowSnob]

For a motor requiring 91 at sea level I was running 85 at 10,000'.
I'd say run 88 if your 6,000'+ (with a stock sled)

 

[buck50]

i forgot to say that my sled is stock, 05 800 summit x. also in revy, they sell 94 octane gas which is waay more expensive. pretty sure i don't need that gas, bu twas wondering if we need to run 92/91 or can i use the 88/87 stuff instead. i don't have my owners manual in front of me, so i don't know what the recommended fuel is

 

[revpilot]

It's an air density thing, you could get sea level volume into your cylinders on a real cold day at 6k but your sleds' dpm should go into retard before pre-det damages your motor. Short answer is you can run the cheap fuel in the modern sleds with knock sensers without hurting your motor but you may get more performance out of it at times (cold days) if you run premium.

 

[06MXZXRenegade800]

Unless his sled was a spring order it wont have the powertek engine. So no knock sensor.

But its pretty safe to say you wont have any issues running 87oct at elevation, even on the coldest of days! I have a few buddys here that have both Ptek and non Ptek 800s and run 87oct in them all the time. We are at sea level and ride in temps sometimes nearing -50c!

No issues with their rigs yet, though im sure they are on the very edge of deto!

 

[wweverett]

Octane is a retarder to allow the pistons to compress until the spark fires, the higher you go up the less compression you have so the less octane you need. I had a yz450 that would not run on premium this high up but ran great on regular ( try to light premium with a match then try regular and see for yourself the power diffrence)