octane

If you're running @ 8000 feet @ 9.0:1 compression it would probably be a good idea to run no less than 100 octane. @ 12 lbs boost for 8000 feet w/ 9.0:1 compression the very least should be 95 octane. But if you're increasing elevation (say 9,10,11,000 feet), I would increase your octane. I run 110 straight w/ no head shim up to 11,000 feet. Better to be safe than sorry. Seems most guys on here run in the 100's octane for elevations over 8,000. Your best bet might just be to give Dean a call @ Alpine to fix you up just right! Hope this helps

The lower your altitude the higher your octane needs to be.

That is why if you buy gas for your car at sea level the octane of the lowest grade gasoline will be at least 89 but where we live at 4500 ft our lowest level octane is 85.

So if you are running 10lbs boost at sea level you probably need 100 av gas or maybe even race gas 110 octane.

But where we ride at 8-10,00 ft. we can run 20 lbs with 110 race gas.

Also: As mentioned by TurboT your engines compression is a vital factor. The higher the compression ratio the higher your octane needs to be, then add boost and it becomes even more critical.

You need to contact the person that built the sled and find out if it has low compression pistons, head shim, etc. Then call Alpine and tell them what elevation you ride at and how many pounds of boost you want to run.