[sledlover]

The Accord result was a fluke as they stated in the article.
In the 650, I suspect that neither fuel would show a major difference if used in the ethanol mode. A minor difference could possibly be because the ethanol mode runs richer and the premium fuel if non-ethanol would be even richer. If both are the same % ethanol fuel, then it should be the same power.

One of the most important things about fuel is freshness. This affects full vaporization. Fuel will not burn completely in the combustion chamber if it doesn't vaporize. Premium fuel is often stale due to less usage. This is extremely important in a 2 stroke engine. DTR has seen loss of hp simply due to stale fuel so they test all fuel used for this characteristic using an RVP tester. Fuel that doesn't completely burn actually causes lean mixtures and can seize the engine even though an AFR gauge reading or fuel flow appears safe. Many so called "cold seizures" are actually caused by poor fuel vaporization. Warming the engine up before riding is really helping low volatility fuel to vaporize.

A FITCH fuel catalyst cannister is designed for this problem and is what I recommend be used in all my and my friends/customer's sleds.

Not fair to chalk something up to a fluke if your don't like the results. That is why we test things.

I would bet a statistician would say the results of the Accord, Mustang and Dodge Ram were statistically insignificant. They even kind of say that in the article.

Can you tell the snow is melting? When we are arguing about silly stuff like this!

 

[1fastpolaris]

I'd like to add that the computer has no idea what type of fuel YOU put in the tank. It only delivers the fuel to the engine based on which setting you select, and a few other parameters. The end user needs to use some good judgement when filling up and selecting the fuel setting. IMO the premium NON setting should only be used if the fuel is indeed fresh and at least 91 or better. The 650 doesn't seem as sensitive, but the 850 will still experience mild DET with just 91 NON ethanol. I don't think it's enough octane, just barely. They run really well on 93E10 in the NON ethanol mode. I've changed my ways and leave it in Ethanol mode now unless I know I have good fuel.

 

[stnod]

I'd like to add that the computer has no idea what type of fuel YOU put in the tank. It only delivers the fuel to the engine based on which setting you select, and a few other parameters. The end user needs to use some good judgement when filling up and selecting the fuel setting. IMO the premium NON setting should only be used if the fuel is indeed fresh and at least 91 or better. The 650 doesn't seem as sensitive, but the 850 will still experience mild DET with just 91 NON ethanol. I don't think it's enough octane, just barely. They run really well on 93E10 in the NON ethanol mode. I've changed my ways and leave it in Ethanol mode now unless I know I have good fuel.

The bold disturbs me a bit. We ride in an area where 91-non is widely available and FRESH. If the 850 can't run with that fuel in the 91-non mode without DET .... that's just flat out wrong. I never had problems with DET on my '19 XC 850 when using 91-non ethanol and the 91-non settings. Did Polaris tighten up their fuel specs / parameters for 2021???

 

[sledlover]

I run 91 non-eth in my 800 HO from quick star, never had a DET sled set on premium.

 

[1fastpolaris]

The bold disturbs me a bit. We ride in an area where 91-non is widely available and FRESH. If the 850 can't run with that fuel in the 91-non mode without DET .... that's just flat out wrong. I never had problems with DET on my '19 XC 850 when using 91-non ethanol and the 91-non settings. Did Polaris tighten up their fuel specs / parameters for 2021???

I'm agree it should be fine. I've had a few occasions where it where it reached max DET and went into limp mode running 91 NON in the NON setting on my 850. Haven't had enough seat time with the 650, but the 650 should be less sensitive.

 

[razor16]

The bold disturbs me a bit. We ride in an area where 91-non is widely available and FRESH. If the 850 can't run with that fuel in the 91-non mode without DET .... that's just flat out wrong. I never had problems with DET on my '19 XC 850 when using 91-non ethanol and the 91-non settings. Did Polaris tighten up their fuel specs / parameters for 2021???

Haha, I hope not. I just had the latest flash installed. I always run 91 non ethanol premium, and to this point I havent seen 1 DET warning. I sure hope that doesn't change with the new tune.

 

[Northbushrider]

I get 12-13 mpg. Sips oil though. Cost between oil and fuel probably about the same as my 850.

Are you talking Imperial gallon, if so the Yanks are getting way better mileage.

 

[Northbushrider]

I'll take a old Sun tach anyday

YUP! Keep it simple.

 

[northstarrick]

my 650 has not been beat by any other 600,700,800,and one 850 tied it. snow radar runs 660' in the ethanol mode. with 91 mobile fuel. not one det code on my sled. i see as many as 30+ det codes on most put on the computer. 850's guys running in the non ethanol mode with 91 non eth. fuel? in our testing there is a very minor performance gain between these modes. only in long runs do we see maybe a sled length at times? is it worth risking det? nope det rattles shit apart like locating pin's etc. all the motors i rebuild have repeated det codes on them? mostly 800's. if i run in non eth. mode i run 93-94 octane fuel. 91 is not safe enough on the 800's or 850's.

 

[x2700]

I’d say the one greatest plus of the 650 is no dreaded rpm fade that most seem to find with 850.
650 that I ran was dead on rpm wise or a bit high at every wack of the throttle!!

 

[geez150]

Part of the reason I bought the 650 3 times now, VS. An 850. They just run. No goofy rpm issues and this or that. Are they the fastest, nope. But they are a solid run every weekend engine.

 

[calltrex]

i dont care about fuel economy but i took a 650 137" for a whole weekend. it was painful. lack of power. simply wanting to jump some quick humps on the trail you giver gas and by the time the power come on your way past the hump you wanted to jump. its better then the old 600s but not that much

650 prob good for the average person.

 

[fz583]

I thought the 650 was great, until i got my 850, I'll take the 850 all day long, but I will be avoiding the 900 or 850 boost, cause I know the 850 would be for sale quick.

 

[ExcursionPSD]

i dont care about fuel economy but i took a 650 137" for a whole weekend. it was painful. lack of power. simply wanting to jump some quick humps on the trail you giver gas and by the time the power come on your way past the hump you wanted to jump. its better then the old 600s but not that much

650 prob good for the average person.

Sounds like that 650 you were on, wasn't running very good. Myself and others here with 650's realize they don't have the maximum top end of an 850, but they are plenty quick enough up to 60 MPH. It can pull the skis easily and quickly.

 

[calltrex]

Prob just used to 800. 850s and their Quick response and power.
Never had anything less

Sent from my SM-S906W using Tapatalk

 

[northstarrick]

i have 2 650's 1 850 and my son has a 850. the 650 assault is right beside both 850's to about 80 mph. now these are not stock clutching on any of them. and all have a different set-up. the 22 650 xcr wants to stay planted. it will lift the ski's but it's much harder to do then my 21 650 assault. the 22 xcr 850 is nothing like my 19 850. same thing it doesn't lift the ski's easily. my 19 slightly modded 850 will carry the ski's 2' off the ground for 660' + @ 85-90 mph. my 650 assault will pull the ski's at will. the 850 has more grunt but both 650's are sneaky fast. and will blow any 600 off the lake. not even close. f-7 nope not as fast. 3 at one radar run only one broke 80 mph. soft snow so not the best but every sled ran in the same conditions. never seen a 600 beat a f-7? my assault in the eth. mode with 60 miles on it went 84 mph so not even broke in in the slow mode according to some? our 800 assault won @ 88 mph. this assault beat my 850 repeatedly.

 

[fastsleddr]

850 rpm fade?? that got figured out in 19/20.

my non stock 650 gets 16-18 mpg . 18 is a bit hard to achieve, but can be done. I can kill it down to 12 too.

 

[Lid2]

850 rpm fade?? that got figured out in 19/20.

my non stock 650 gets 16-18 mpg . 18 is a bit hard to achieve, but can be done. I can kill it down to 12 too.

What did you do to stabalize the rpm on 850

 

[orville-x]

What did you do to stabalize the rpm on 850

I think its most accurate to say people figured out what causes the issue, not what eliminates it. If you have one that does it, you're only going to be able to "manage" the issue...

 

[Sledtuner360]

650’s I have ridden are not as responsive as 850’s. That being said, 650 will stay with 850 for a bit but it is only due to available traction. If all is equal the 850 smokes the 650 as it should. I am not putting them down as they are a great power plant but I will not be going down to one to get 1/2 to a gallon better mileage per tank. Besides if I rode with the 850’s I’m sure it would get same mileage trying to keep up.