I was under the impression that the car had to be Flex-fuel to run e85. I have a 2015 transit van that can run it, but it's not worth it even at the cheaper price because the mpgs go to hell. I get 19 hwy with gasoline, more like 16 with e85. I don't notice any improvement in power.

You could probably tune the engine to run only e85, but flex-fuel engines have special algorithms and sensors to adapt to what kind of fuel is running.


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I was under the impression that the car had to be Flex-fuel to run e85. I have a 2015 transit van that can run it, but it's not worth it even at the cheaper price because the mpgs go to hell. I get 19 hwy with gasoline, more like 16 with e85. I don't notice any improvement in power.

You could probably tune the engine to run only e85, but flex-fuel engines have special algorithms and sensors to adapt to what kind of fuel is running.

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No, you can run e85 in a non flex fuel engine but certain changes have to made. There are some 850s out there running e85 for the extra power but a retune is needed, at least 60# injectors, and an upgraded fuel pump. At least that's how I understand it.

Fuel economy on E85 is significantly worse, like 20-30%. It has a lower energy content compared to gasoline, about 75-80%, so you have to burn more of it to get the same amount of energy output as gas. You might be getting 100-110 octane equivalent, but you'll be filling up a lot more. Availability is definitely a big factor too. How common are E85 pumps around where you live? If they're everywhere then it's not a bad idea at all, might be more expensive in the long run but like you said, there's some awesome benefits

Dustboy's Transit probably doesn't get any more power from E85 because that's how the car is tuned, it's just able to use E85, not to really benefit from it. I'd assume it's like how putting 93 octane in an economy car that's designed to run on 87 will give you absolutely no benefits, because the car's timing will adjust to make it run exactly as it would on 87.

From a tuning perspective, yeah you'll need a sensor that detects what percentage ethanol you're running, and the tune will adjust accordingly. You might have it set up so you're running 250hp on straight 91 octane, and 320hp on pure E85, and any mixture of E85/gas will yield power numbers in that range.

Yeah that makes sense about the Transit. But there are several places here in my area that have e85 and I'm not really too worried about the mpg hit, especially if it's somewhat offset by the lower cost of e85 compared to 93 or whatever. And at the end of the day, it's not my daily driver (AWD V8 4RUNNER AS IF THAT'S ANY BETTER) and most of us get into the upgrading to make more power as the first and primary goal, at least for me.

You mentioned something about a sensor? What are you referring to? My understanding is that you'd just need a tune to run the e85. I wonder how much extra power it yields over conventional grade fuel.

If all goes well here pretty soon, my plan is to install the new BBK and engine mounts. Then once I find a manual, I want to do the swap, upgrade to a 19t from the current 16t, and then switch over to e85.

 

Fuel economy on E85 is significantly worse, like 20-30%. It has a lower energy content compared to gasoline, about 75-80%, so you have to burn more of it to get the same amount of energy output as gas. You might be getting 100-110 octane equivalent, but you'll be filling up a lot more. Availability is definitely a big factor too. How common are E85 pumps around where you live? If they're everywhere then it's not a bad idea at all, might be more expensive in the long run but like you said, there's some awesome benefits

Dustboy's Transit probably doesn't get any more power from E85 because that's how the car is tuned, it's just able to use E85, not to really benefit from it. I'd assume it's like how putting 93 octane in an economy car that's designed to run on 87 will give you absolutely no benefits, because the car's timing will adjust to make it run exactly as it would on 87.

From a tuning perspective, yeah you'll need a sensor that detects what percentage ethanol you're running, and the tune will adjust accordingly. You might have it set up so you're running 250hp on straight 91 octane, and 320hp on pure E85, and any mixture of E85/gas will yield power numbers in that range.

 

Very late, but I've been pumping 1 gallon e85 per 6 gallons of 91 (California's best) for almost a year now and it absolutely makes a difference with almost no loss in fuel economy. I'm currently fbo and custom tune but not tuned for the mix of e85, I just let the ecu figure it out. I tried 1 gallon per 4 gallons gas but that was to much with no tune and didn't idle right and ran lean, but 1/6 seems to be a sweet spot. Even went straight 91 a few months ago, reset ecu and drove the full tank and it felt so sluggish the whole time. So if your in Cali and seeing this, give it a try, especially in the summer.

 

Way to revive an old thread. It’s so old that I scrolled to the top to see who the OP was and then realized it was me 🤣🤣🤣

But yes, my 8 fiddy is currently 100% run on E85 and I can do that because there are plenty of E85 stations around me. I also have the provision built into the tune that in the event that I am stranded somewhere without access to corn, I just tap the throttle pedal with the ignition turned to “ON” and then it switches the map to pump gas so that I can fill 93 from any station.