premium/regular key switch - Snowmobile Forum: Your #1 Snowmobile Forum

360 xrt · 12-31-2012, 10:24 PM

i understand the rules of the switch,but i want to know more.what exactly does this switch do ? some say it gives the engine a different tune,some say it gives the engine more/less injected oil for a different mix ratio. the sled in example is an 02' polaris xc800 sp.

360 xrt · 12-31-2012, 10:28 PM

also i'm in need of speedo gauge bulb (can i use an automotive bulb,what # ? ) and i need to install an inline fuse on my watertemp gauge, (what amperage fuse and do i just use an inline automotive style fuse or do i need something different for the ac voltage)

**BC_Dan** · 12-31-2012, 10:30 PM

Switching the key to premium advances the timing about 3 degrees so that you can take advantage of the premium fuel's resistance to detonation. It has nothing to do with the oil. The oil pump is a rotary gear pump driven by a belt off the mag end of the crankshaft and is dependent on RPM and oil lever position. It's 100% mechanical.

360 xrt · 12-31-2012, 10:34 PM

thanks dan. so that being said and the history of the crankshaft issues i've been told of these engines,do i just leave it on the regular setting (giving up somehorsepower) or let it rip

either way ,i run 92 octane in it.

360 xrt · 01-01-2013, 09:21 PM

will running this sled in the premium setting shorten the life span of the crankshaft,or is that going to be dictated by my right thumb

**BC_Dan** · 01-02-2013, 12:55 AM

It shouldn't. Several things to do to help the crank live a long life...

Get the primary balanced. Polaris doesn't do a good job of that.

Add the wide bearing kit to the PTO end to spread the force of the crank over a greater area. That can be spendy, and some places require the cases and the crank so they can ensure the case has not started to fail.

Add an engine plate. The plate stiffens things up a bit and helps keep the bottom end planted.

There are also push stops and torque links that can be installed so the engine stays square. That helps belt life more than crank life, though.

When I had my two 800 Edge sleds, there wasn't 2 MPH difference between the regular setting and the premium setting. It did seem peppier on the premium setting. I run 91 non-alcohol fuel.