I have finally got what I believe to be reliable specs on the FS/FST powered snowmobiles. You are welcome to peruse/discuss.

Please be aware that the non-turbocharged FS has a separate spec page from the Turbocharged FST.

The attached file requires Adobe Acrobat Reader to display or print it.

If anyone finds an error or mistake, PM me, I will try to keep ONE post with the 'corrections or updates' for it. I did not prepare this myself, it is of course courtesy of the NORTH STAR

Corrections or Updates to FS/FST specifications document.

That's so cool how the clutching specs change so little as altitude changes.

That could very well be my next sled if the aftermarket guys can lighten it up relatively cheaply...

0w-50 synthetic...You arent going to find that kinda oil at Wal-Mart...

Matt, with the turbocharged EFI closed loop motor, I am a little surprised the clutching changes at all, Polaris said it would have the same horsepower at 8,000 foot as it did at sea level. That certainly would be possible. If it has the same horespower and the same torque, there wouldn't be a need to change clutching. The changes are fairly small and they don't start until 6,000 feet, so maybe they have more to do with operating in different conditions: deep snow, more up and down hill, need to improve backshifting or throttle response???

I want to weigh the silencer, but I'm waiting for a couple strong guys to get back from vacation to help me get it out. I can tell you the driveshaft is sure light, and the M10 136 is also reasonable in weight for a long-track, long-travel 3 shock suspension with 6 bogies on the rail and 4 rear idlers. (yes, I already added one, it's tradition). Even the Computer (ECU) is in lightweight protective armor under the boost box in front of the fuel tank.



0W-50 is pretty rare grade isn't it. I suppose Polaris is aware that there is not much availability of that on this planet, other than at a Polaris dealer, when they get their shipment in. The similar motor in the PWC used 20W-50. I can appreciate the 0W side of it for winter starting, I use 5W-30 Amsoil in my turbodiesel for winter starting without being pluggged in.

I do feel that the 50 grade which describes viscosity at 212F is overkill in this application, and may well waste horsepower, without providing much benefit. I am preparing a more detailed explanation. (you've been warned)

It weighs 27 pounds. No need for it to be that heavy IMO. I'm sure there are plenty of places to lighten the thing up. Bigger turbo, direct pipe off the gate...

Since I have one off right now, I can tell you it weighs 22 lbs. I am 225.5 and holding the muffler I am 247.5

Well, your diesel doesnt spin at 5,000-8,000 rpm all the time. Im sure that part of it is Polaris covering their a$$.
I know that people who have turboed RX-1s still use 5w-30, so perhaps it is overkill.
I doubt that you would see much of a performance gain by switching from 0w-50 to 0w-30...
If I spent $8000+ on an FST, I think Id run the grade of oil that Polaris suggests.