Flex Fuel?

snowcheck163 said:

What about mixing like people do with AV gas. Or just stay away.

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Its actually a great fuel for turbo application, not better than AV, but really good still. Especially if you can get it 'fresh' (as others note, it can attract water).

The problem isn't the fuel, its the way our fuel injection and fuel system was designed. Simply, E85 is less energy dense. Hence, you need to significantly richen the fuel curve up to properly run it, otherwise you will be *VERY* lean.

This is why our sleds have an E10 mode, it richens the curve up.

Worth noting, I know of guys in the car world who tune specifically for it. They usually increase injector size, fuel pump size, and build a tune specifically around E85.

My .02 to OP don't use e85 in anything that's not made expecially made to burn it(flex vehicles). I'm not 100% sure but I don't think the injectors can flow enough fuel to run on 85-100% alcohol. Have had alcohol race car motors and it takes a lot of fuel just to idle, let alone run at 8k rpm.

The problem is the stoichiometric air fuel ratio is ~9.8 compared to 14.7 for pump gas. If you can tune for it it's great for making power, but you will drink ~30% more fuel. There is a slight thermal efficiency gain with ethanol that makes up for the BTU deficit in relation to the stoich value

Like others have said, and I will elaborate more on it. Due to the higher fuel demand (~30%) you now need to haul that much more fuel around...

This means everything needs to be reworked, you need a fuel pump and injectors that can flow 30% more as well as mapping to handle it. Also due to the very high moisture nature of snowmobiling your VERY likely to have issues with moisture especially if your not running your sled bone dry and buying fuel on the way to the hill every day.

It is a very cool fuel with some awesome traits, BUT, for back country sled use, it is not the best fuel. Av gas is a better alternative if high octane and low cost is your goal.

I have a 16 assault with a silber kit here in Iowa, running 3lb spring, last ride of season was out of gas and put in 3-4 gallons of e85 to get home 25 miles, ran great, no codes, no Det nothing. Smelled great also. If these things can run 10lbs with stock injectors and pump evidently the computer will compensate enough to run e85 like I did at low boost. Idk how else to explain it but my sled seemed to love it

JJ_0909 said:

Its actually a great fuel for turbo application, not better than AV, but really good still. Especially if you can get it 'fresh' (as others note, it can attract water).

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Ummmm what??

E85 is leaps and bounds better than AV for turbo applications. It's octane equivalent is more like 105-110. It burns super cool and you can run a LOT more timing than pump or AV.

Now for reasons others have mentioned it might not be the best for sleds ....

An issue with E85 also is if a fuel system is not specifically designed for it. The rubber in the system from hoses to O-rings may be susceptible to breaking down with the use of E85
So I wouldn't run it in a sled at all

14RMK144 said:

An issue with E85 also is if a fuel system is not specifically designed for it. The rubber in the system from hoses to O-rings may be susceptible to breaking down with the use of E85
So I wouldn't run it in a sled at all

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they said the same thing about cars but ive ran it in my street evo for 5 years and we've ran it in our race evo for two years without issues.

arent the injectors used in our sleds bosch with ss internals?

Petroleum based fuel is the best for sleds. Unless you have full access to your tuning and know what you are doing, you will only make less power and likely cause premature wear. Alcohol burns cooler than petroleum which may seem beneficial, but it affects gap tolerences in your motor. Also, alcohol is abrasive compared to petro. Alcohol motors require the use of additives to increase lubricity in the motor and have different gap tolerances to account for those issues.

So why do people run alcohol? The answer is TIMING...alcohol drastically increases octane characteristics allowing the tuner to increase the timing curve. In tuning, timing makes power up to an optimal point. If you simply run alcohol, the sled will make less power because alcohol contains less energy than petro without more timing. Also, if your engine is optimized well from the factory, additional timing may be of little use.

Like previously mentioned, stoich changes too. The target afr on alcohol is much lower than petro meaning it takes more parts of fuel to parts air to optimize combustion. Adding alcohol leans your sled out. Most engines are design to manage up to 10 to 15% since that is available at the pump. This is a problem because you will get sunstantailly worse mileage per tank and reduce your riding time as the alcohol mix increases.

Finally, alcohol really shines when using power adders like turbos, superchargers, nitrous and/or really high compression. As boost increases, you get closer to causing detonation which requires the tuner to reduce timing on the same octane. Alcohol is used to remedy this issue in race applications where boost is 40 psi and higher and fuel mileage is not a concern. Alcohol allows for much more timing to be used under extreme boost. In mild applications, alcohol is injected for intercooling effects in the form of water meth injection whereby water helps cool the charge. On street cars, water meth is popular since you can run more boost on pump gas (driven by availability and cost). So, unless you are running crazy boost, I would stay with petro since it is a lot less headache.

Sorry for the really long post, but I thought most people do not really appreciate alll that goes into that decision.