Corn tune on a turbo M7?

Aug 30, 2021
5
0
1
Gillette, WY
I have a '06 M7 EFI running a boondocker turbo kit, along with all supporting mods. I'm wondering if anyone has gotten something similar to run on E85 and what the pros and cons are. Right now its set up to run 12PSI on 110 octane, but I cannot afford to go ride as much as I'd like just because of the cost of fuel. So I've done some research, and this is what I've came up with:
-E85 is usually about 100-106 octane (R+M)/2 and therefore is incredibly resistant to knocks and premature ignition, which is what I am trying to avoid running high compression, high boost, and hard use. That is the reason I have had to run 110 octane.
-E85 is highly corrosive to fuel systems that are not compatible with it. Is the fuel system in my sled going to be able to handle it?
-E85 usually needs to run 9.8:1 instead of the 14.7:1 I have it running right now. I do have the secondary Boondocker fuel rail and injectors on top of my stock fuel injection system, so I should be able to just change my fuel trim levels until it is giving me the AFR I am needing?
-E85 gets worse fuel economy because of the aforementioned increased fuel usage. In my area E85 is somewhat difficult to find, however I should be able to just fill up multiple 5 gallon tanks and be good for a weekend.
-E85 is typically harder to get started in cold weather, which is the obvious climate of a snowmobile. Will I have issues staring my sled when I first get to the mountain? Will I just be able to use a can of starting fluid to get it going in severe cold?
 

boondocker97

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Oct 30, 2008
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Billings MT
Not much to add, but interested to hear the answers for personal knowledge. I remember the early Firecats 03-04 had the ethanol switch to be able to run lower amounts (10%) in blended pump gas. That should be somewhat encouraging that Cat was designing their fuel systems to be somewhat compatible with it. Not sure if that means they can tolerate the higher concentration.

How far do you typically go on a ride? The decreased fuel mileage would be a big deterrent for me since I need to be able to go 50+ miles on a tank to make it back to the truck. Don't really like the idea of packing giant cans on the tunnel. How far would you have to back the boost down to run AV gas?
 

kiliki

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Dec 27, 2008
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Nampa, Idaho
E85 is good for the octane but once you get below 20* it turns into a problem to get it started. One of the bigger properties is the cooling it bring to the motor this is why it works so well on hot days to reduce combustion temps. This will be a lost benefit and will turn into a liability to keep pipe and engine up to running temp. you will also have a fair bit more fuel to the mix and this will be going backword from trying to spend less on gas when you would require more E. for the price not worth it on a sled IMO.
 
Aug 30, 2021
5
0
1
Gillette, WY
E85 is good for the octane but once you get below 20* it turns into a problem to get it started. One of the bigger properties is the cooling it bring to the motor this is why it works so well on hot days to reduce combustion temps. This will be a lost benefit and will turn into a liability to keep pipe and engine up to running temp. you will also have a fair bit more fuel to the mix and this will be going backword from trying to spend less on gas when you would require more E. for the price not worth it on a sled IMO.
As I stated in the original post I think I would be able to just use starting fluid to start it, which won't be a big deal as I also run a few vintage sleds and those need a bit of convincing to get started some days as well. I do see your point in there being a possible issue keeping everything hot enough, because especially on a turboed sled, if my turbo can't get up to temp that could cause serious power decreases. However on your comment of the fuel economy causing me to spend the same thing, I have read that E85 usually requires between 20-30% more fuel, however the cost per gallon is 25% what 110 octane is, therefore my cost per mile should decrease.
 
Aug 30, 2021
5
0
1
Gillette, WY
Not much to add, but interested to hear the answers for personal knowledge. I remember the early Firecats 03-04 had the ethanol switch to be able to run lower amounts (10%) in blended pump gas. That should be somewhat encouraging that Cat was designing their fuel systems to be somewhat compatible with it. Not sure if that means they can tolerate the higher concentration.

How far do you typically go on a ride? The decreased fuel mileage would be a big deterrent for me since I need to be able to go 50+ miles on a tank to make it back to the truck. Don't really like the idea of packing giant cans on the tunnel. How far would you have to back the boost down to run AV gas?
I did not know that about the Firecat fuel systems, that is very encouraging. The decreased range would somewhat be a downfall of it, partially because there is no way any of the lodges near me have E85, so I cannot fill up halfway through the day, but I could run a tunnel tank for an extra few gallons and could also possibly outfit my trailer with a ~20-30gal fuel cell for multiday trips.
 
Oct 8, 2009
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43
I run E85 on my turbo viper mountain sled. And, I have no problems getting to operating temp, nor is starting an issue. But, I run a Motec M130 with IGN1 race coils, so my ignition is way stronger than a factory system.

Next, all E85 has some water in it, so you need compatible fuel system components with billet or stainless internals. Otherwise, you will rust your components from the pump to the injector.

Third, you are under estimating fuel consumption. Your current fuel system probably won't do the job because E85 take 35 to 40 percent more fuel. For reference, I run dual idx1000 per cylinder (2000cc total). Your probably in the neighborhood of 500 to 750cc per cylinder. For sake of discussion, if you have enough injector, you probably need a lot bigger fuel pump. I run a 350 liter per hour pump. Yours is probably 150 or less. I tell you this, so you can contemplate the switch.

Fourth, if you can ignite the alcohol, you have to get bigger injector drivers and something that can drive them.

Finally, Just rebuilding my fuel and ignition systems to truly run e85 cost me several thousand all said and done on top of the cost of the Motec, which runs all of it. It is a game changer for someone running big boost like me. I can go over 30 psi if I want too. But, that is waaaay to gangster. With my air to water and e85, my intake temps were 75 degrees F at 24 psi when it was 32 degrees outside and my snorkel was under my vented side panel. Long story short, the financial motivation isn't true. You need a pile of cash to get there.
 

PaulAnd

Well-known member
Premium Member
Oct 17, 2010
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Northern IL.
E85 is inconsistent especially in the winter
I’ve never seen higher than 70%
At the pump in the summer

E85 on a sled might see lots more moisture so shelf life goes down
A stand alone with a good safe tune
Injectors and pump
Flex fuel sensor
Really good fuel filter
E85 is awesome done right,
but the right AV fuel blend sounds much easier
14:1 sounds lean


Sent from my iPhone using Tapatalk
 
Aug 30, 2021
5
0
1
Gillette, WY
I run E85 on my turbo viper mountain sled. And, I have no problems getting to operating temp, nor is starting an issue. But, I run a Motec M130 with IGN1 race coils, so my ignition is way stronger than a factory system.

Next, all E85 has some water in it, so you need compatible fuel system components with billet or stainless internals. Otherwise, you will rust your components from the pump to the injector.

Third, you are under estimating fuel consumption. Your current fuel system probably won't do the job because E85 take 35 to 40 percent more fuel. For reference, I run dual idx1000 per cylinder (2000cc total). Your probably in the neighborhood of 500 to 750cc per cylinder. For sake of discussion, if you have enough injector, you probably need a lot bigger fuel pump. I run a 350 liter per hour pump. Yours is probably 150 or less. I tell you this, so you can contemplate the switch.

Fourth, if you can ignite the alcohol, you have to get bigger injector drivers and something that can drive them.

Finally, Just rebuilding my fuel and ignition systems to truly run e85 cost me several thousand all said and done on top of the cost of the Motec, which runs all of it. It is a game changer for someone running big boost like me. I can go over 30 psi if I want too. But, that is waaaay to gangster. With my air to water and e85, my intake temps were 75 degrees F at 24 psi when it was 32 degrees outside and my snorkel was under my vented side panel. Long story short, the financial motivation isn't true. You need a pile of cash to get there.
That is incredibly helpful information I appreciate it. 30PSI is absolutely insane for a sled, that's incredible. I will have to do a bit of looking on my sled, I know I have the Billet Boondocker Fuel Rail and I have a few other aftermarket fuel system parts but after reading what you said I doubt if I will be able to push my system hard enough to do what I want.
 
Aug 30, 2021
5
0
1
Gillette, WY
E85 is inconsistent especially in the winter
I’ve never seen higher than 70%
At the pump in the summer

E85 on a sled might see lots more moisture so shelf life goes down
A stand alone with a good safe tune
Injectors and pump
Flex fuel sensor
Really good fuel filter
E85 is awesome done right,
but the right AV fuel blend sounds much easier
14:1 sounds lean


Sent from my iPhone using Tapatalk
Yeah its looking like I'll be stuck running AVgas. I thought the E85 tuning would be a pretty cool thing to make run, but it looks like I'm gonna get in over my head, both financially and practically.
 
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