[z440snopro]

so the drag races have the set date for March 3. Enterying my 2000 z440 sno pro that i've been playing with all fall and winter to get just right. I want to run AV gas thast 100octane but unsure what i need to change to run it, do i change the timing 2degrees advanced on the stator plate, just like you advance the sno pro's with the timing dial to advance 2. Do i need to go up one size in the main jet. i'm not exactly sure what to do to run the stuff but i'd like to run it.

 

[Tomcat-1]

Why do you want to run the AV fuel? Remember that a higher octane fuel will not add HP to a stock engine, but will control the burn of a modified one. If you have cut the heads and increased the ignition timing, the engine will need a fuel that can control detonation. A "VP Red " may be your best bet.

 

[z440snopro]

the heads have been cut .015", I left the timing at the stock 16degree's advanced that it was. I never herd of a "VP Red". Question though since it comes to that, why can the 01-03 z440 sno pro's run AV gas or pump gas just by the turn of the timing dial??

 

[Tomcat-1]

VP red is a race fuel produced by VP Racing Fuels Inc. It is rated @ 105 octane and has a specific gravity of .730 - .745 @ 60F.
If the timing is increased, the burn time for the fuel charge increases during the stroke. If the fuel can not control the burn, the fuel charge can "explode" in the cylinder causing piston damage.
Remember that compression / increased burn time, builds heat as the mixture is "squeezed" in the cylinder.

 

[z440snopro]

so all in all, your saying i shouldn't adavnce my timing, or run the 100octane AV gas?? i don't know where i can get that 105 gas, i'm in Atikokan, Ontario, that might be pretty pricy gas for not alot of gain.

 

[Tomcat-1]

We owned a 2001 Z 440 Sno Pro, great sled! I think the stock engine can run on 87 octane "pump fuel" so if you have cut the heads, maybe 92 octane pump fuel would be just fine. What you need to do is run the fuel for a short distance at wot. Stop the engine while holding the throttle at wot and stop the sled. Inspect the electrode of the spark plug and piston for signs of pitting or a "sand blasted" look. This will also give you some idea what the jetting should be for the given day by looking at the piston wash.
AV fuel is ok, alot of guys use it, it's just designed for air cooled aircraft engines.

 

[z440snopro]

i looked at the pistons just the other day, the spark plugs are black/brown but my pistons are clean all around the edges, i thought it might have been jetting so i leaned it out about more to get the brown on the plugs but the pistons were still bare around the edges, i run 92oct.

 

[MIDMICHIGAN440]

I own one of the 2002 440 Z snow pro's. It has been one of the funnest best overall running sleds I have ever owned. I am really liking having a sled right now that doesn't have a radiator on it. The thing abosolutely rocks for a 440 fan. I have never even had a 440 liquid sled that has had this kind of performance and durability blended into a perfect package. I go riding with people and they are always quick to judge the sled a dud when they find out it is a 440 fan and then after we go riding they are usually quite impressed with the capabilities of that sled. I rode it tonight in about 15 degree weather and it just was screaming. If it holds up as good as it has so far I will be an extremely happy camper with this thing. I can really ride it hard and not worry about to much on it. Very easy to maintain. I had a 97 ZR liquid 440 sno pro and I think this 2002 fan would beat it in every way including top speed. I have tweaked about 93 mph from the fan and maybe close to that with the 97. I love the deep lug track and the raised handle bars and the wide running boards. It is very light to handle through the woods and trails too. I have never turned the timing adjust on it. I never had a performance manual to know what to do with it. I know am very pleased with it though. I have a 2001 ZRT that sits in the garage most of the time because the 440 is so fun. Later.