Ethanol mode vs non ethanol?

Golanda · Oct 23, 2017

Does anyone know what the difference between running in ethanol mode and non ethanol mode is?

I was wondering because Bikeman says to run the AXYS in Ethanol mode with non-ethanol fuel when using their pipe.

tuneman · Oct 23, 2017

Ethanol mode uses more fuel to keep the hotter mix from detonating(ethanol burns hot). Non-ethanol leans it out a bit for a crisper throttle. I suspect they recommend the richer mix because their pipe is much less restrictive than stock, which can make an engine run lean.

bobback · Oct 23, 2017

When I had my Pro - local head mechanic at Polaris dealer, who is very reputable / has worked there for a long time; said even if running non eth fuel to set mode to eth fuel; as even non eth fuel has some eth in it.

retiredpop · Oct 23, 2017

bobback said:
When I had my Pro - local head mechanic at Polaris dealer, who is very reputable / has worked there for a long time; said even if running non eth fuel to set mode to eth fuel; as even non eth fuel has some eth in it.

Not sure I believe that. Only way you could get ethanol would be the residual fuel in the hose at the gas pump when the previous user filled up with ethanol. If in fact the supplier was putting some ethanol in the non-ethanol and it could be proven they might be liable for engine damage.

RMK-King · Oct 23, 2017

Ethanol mode runs 3% richer, I don't believe it changes the timing any.

bobback · Oct 23, 2017

retiredpop said:
Not sure I believe that. Only way you could get ethanol would be the residual fuel in the hose at the gas pump when the previous user filled up with ethanol. If in fact the supplier was putting some ethanol in the non-ethanol and it could be proven they might be liable for engine damage.

I see your point.

My 13 Pro I always ran eth free gas, kept setting on sled at eth gas; sold it with 1453 miles and had never had an issue with sled. Guy who bought sled had compression checked and that passed with flying colors.

aksledjunkie · Oct 23, 2017

bobback said:
I see your point.

My 13 Pro I always ran eth free gas, kept setting on sled at eth gas; sold it with 1453 miles and had never had an issue with sled. Guy who bought sled had compression checked and that passed with flying colors.

Makes sense, sled runs rich on ETH mode.

retiredpop · Oct 23, 2017

Sledmax said:
Ethanol mode runs 3% richer, I don't believe it changes the timing any.

bobback said:
I see your point.

My 13 Pro I always ran eth free gas, kept setting on sled at eth gas; sold it with 1453 miles and had never had an issue with sled. Guy who bought sled had compression checked and that passed with flying colors.

Yeah, it's not like it's dumping mega amounts of extra fuel into it. Kind of cheap insurance against lean burndowns in my opinion.

kylant · Oct 23, 2017

what setting to run with slp pipe/can and 100 octane non-ethanol pump or VP VPR 100 octane leaded??

SRXSRULE · Oct 23, 2017

kylant said:
what setting to run with slp pipe/can and 100 octane non-ethanol pump or VP VPR 100 octane leaded??

If the Pipe/can are the only changes from stock you would never want or need to run 100 octane. More octane doesnt make more power, a little extra for insurance is fine, but your way past that with 100.

91 octane is all you need with that pipe.

Golanda · Oct 23, 2017

Bikeman said it runs a little richer to prevent detonation. I ran it all last year on non ethanol mode without any detonation issues so I'll not to worry about it. I always run non ethanol fuel.

damx · Oct 24, 2017

It adds 2 or 3 % fuel across the hole map and takes a bit of timing away 8300 ish and above.

peaceofwork · Oct 24, 2017

SRXSRULE said:
If the Pipe/can are the only changes from stock you would never want or need to run 100 octane. More octane doesnt make more power, a little extra for insurance is fine, but your way past that with 100.

91 octane is all you need with that pipe.

Interesting point and I agree but here is what I ponder - whare I live we can get non eth fuel , it's chevron 94 oct and it's expensive but ethanol free and I like that. Now here is the kicker I can pull up to the airport and get 100ll for the same price or a few cents less. It's ethanol free and the sled seems to run good on it . Often the sled sits a month or two between uses does av gas stay stabil longer?
What is the lesser evil ethanol in the fuel or the 100 octain ?

tuneman · Oct 24, 2017

peaceofwork said:
Interesting point and I agree but here is what I ponder - whare I live we can get non eth fuel , it's chevron 94 oct and it's expensive but ethanol free and I like that. Now here is the kicker I can pull up to the airport and get 100ll for the same price or a few cents less. It's ethanol free and the sled seems to run good on it . Often the sled sits a month or two between uses does av gas stay stabil longer?
What is the lesser evil ethanol in the fuel or the 100 octain ?

UL94 is essentially the same as 100LL, minus the lead. So, between the two, you're better off going with the 94, to assure no lead buildup on stuff. Same vaporization, so both will store the same.

peaceofwork · Oct 24, 2017

100 ll avgas is not 100 octane?

icr · Oct 24, 2017

peaceofwork said:
100 ll avgas is not 100 octane?

Not if measured the same way as pump gas, then it’s closer to 96. Avgas will tend to have poor performance in sled engines, if you can’t tell a difference and it’s convenient then run it. Might have to change the exhaust sensor a little sooner but that’s about it.

AndrettiDog · Oct 24, 2017

Always a fun conversation.

When trying to get the most HP, you want to run as low of octane as you can without detonation. That's what burns the hottest and translates to more combustion. Race fuel on a stock sled does not make sense!

I had really good luck running my Pro's on non-ethanol mode even with ethanol fuel. I ride above 10k most of the time and the ECM is already running the sled richer at that elevation. Never, not even once, did I have detonation. Sleds ran so much more crisp and a noticeable increase in power. I don't run my Axys this way because I have the SLP stage II and it just flat works the way it is setup (it also has more HP than the Pro's did).

Now, there is always the argument about reliability. The more octane, the less explosion/combustion you have in the motor (not as hot). So, yeah...it's going to make the motor last longer in identical conditions. But you won't have near as much power or fun!

Ratchit · Oct 24, 2017

Sledmax said:
Ethanol mode runs 3% richer, I don't believe it changes the timing any.

Correct , about 3% richer .

It depends on the year too. 15's are the richest map, 16's were leaner, 17's are a better map all over .

If ur running a bmp pipe with no bd. it does lean a little around 8000 rpm plus . Just run it with good fuel in non ethanol mode. If it don't det. That's good, if it does, put in e mode

black z · Oct 24, 2017

tuneman said:
Ethanol mode uses more fuel to keep the hotter mix from detonating(ethanol burns hot). Non-ethanol leans it out a bit for a crisper throttle. I suspect they recommend the richer mix because their pipe is much less restrictive than stock, which can make an engine run lean.

Ethanol actually burns cooler, in 4 stroke applications you pick up thermal efficiency gains when running ethanol. Ever tuned a car for E85? Often times the intake and carburetor will be cool to the touch compared to a comparatively tuned gasoline engine. Especially with E98. The problem with high ethanol blends is the volatility of ethanol at low temperatures, and the reduced energy density per unit. ~30% decline for E85. E85 is actually blended closer to E70 in the northern states for the colder months.

tuneman · Oct 25, 2017

black z said:
Ethanol actually burns cooler, in 4 stroke applications you pick up thermal efficiency gains when running ethanol. Ever tuned a car for E85? Often times the intake and carburetor will be cool to the touch compared to a comparatively tuned gasoline engine. Especially with E98. The problem with high ethanol blends is the volatility of ethanol at low temperatures, and the reduced energy density per unit. ~30% decline for E85. E85 is actually blended closer to E70 in the northern states for the colder months.

I stand corrected. Geez, where was my brain that day!? Just goes to show, never trust the internet. You're right, ethanol burns cooler and has a lot less BTUs per gallon of gas. Now to completely contradict, but correct, myself. Ethanol doesn't like to burn, especially in cold weather. Thus, the reason black Z mentioned E85 goes to E70 in the cold states. So, the ethanol mode richens the fuel to get a consistent burn. Otherwise the inconsistent burn will cause detonation issues. Now I'm off to get more coffee...

Ethanol mode vs non ethanol?

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