6.2L --E85--MPG and performance?

[03blackz71]

I have less than 1/8 of a tank of gas left in my truck and have been thinking about switching to E85 from 93. What kind of gas milage you are getting with your 6.2L with E85 and what is the difference on performance with the E85? Also if you switched to E85 and switched back to 93, did you get the same MPG as before using E85?

[RyanbabZ71]

10-11 mpg on E85

 

 

Ryan

[03blackz71]

How is the performance between the E85 to 93?

 

Right now E85 is 2.99 and 93 is like 4.15+ so it is in the cheaper range.

[Cowpie]

You will take a hit on mpg using E85, but you have to look at the cost differential and the mpg difference and figure out the cost per mile. When prices are right, the E85 might just give you the better value. I run E85 sometimes, and other times i run E10 or regular. Prices fluctuate and I change what I use based on those fluctuations.

 

I can't speak to the 6.2L, but the actual performance charts from GM on the 5.3L show, without any special tune, a 10 hp jump using E85 and a 6 lb torque increase, over using 87/89 octane gas. Might just be me, but I tend to feel a little improvement in the butt dyno when E85 is in the tank.

 

One thing about using E85 and switching with 93 octane, you can use a 93 octane tune on the ECM and never have to change tune. E85 has a 100 octane rating. You can just switch fuels at will. I use a 93 octane tune when I run E85, and switch to a 87/89 octane tune when I switch fuels because price variances changed. Your mpg you were getting with 93 octane will return when you switch back to 93. Won't do it overnight, as you will still have some E85 in the tank on that first switch to premium.

 

Basically, there aren't any real negatives to switching back and forth. And at least one real benefit, in that you can switch at will as the prices change and get the best value year round. I tend to find the break point, for me, is when E85 is at least 80 cents a gallon less than the other fuels. Which when it comes to premium, is most the time in my area.

[RyanbabZ71]

I have no data but the truck seems to have more pep on e85. Seems sluggish to me with 93

 

 

Ryan

[02suburbanZ71]

Due to the amount of compression with the 6.2 you will see some gains with e85. Yes you would get the same mpg when going back to 93

[SnakeEyeSS]

Anyone remember the post that said you have to switch fuels on empty tanks or it will permanently jack your enthanol % on the ecu

[MikeNH]

Anyone remember the post that said you have to switch fuels on empty tanks or it will permanently jack your enthanol % on the ecu

You need to pump at least seven gallons, ideally more.

[00Silverado4x4]

You need to pump at least seven gallons, ideally more.

I've read through my manual several times regarding refueling and still haven't found anything that states this. Was there a change once the '07NBS came out or something?

 

Now my wife's Jeep does say to pump minimum of so much and drive for so long and when not to switch fuels...odd.

[SnakeEyeSS]

I've read through my manual several times regarding refueling and still haven't found anything that states this. Was there a change once the '07NBS came out or something?

 

Now my wife's Jeep does say to pump minimum of so much and drive for so long and when not to switch fuels...odd.

There was a GM tech that posted on here because they were seeing a lot of truck coming in that needed the ECU wiped and reflashed, because over time it gets so confused about what gas is in the tank it gets "stuck" thinking a certain percentage of ethanol is in the tank.

[Cowpie]

I have never switched fuel until I was at least to less than 1/2 tank of fuel left. Just me. No documentation anywhere that state to do it that way. Just made sense to have more than half the tank gone before filling with another fuel, either E85 to gas or gas to E85.

 

Now to keep the ECM from getting all messed up is not about how much fuel you put in, it is about how long you drive after filling up with another fuel. The recommendation in my 2013 manual is that the vehicle be driven at least 7 miles after fill up so that the ECM can fully recognize the new fuel and make the adjustments it needs to. It does not specify how many gallons. I will have to dig around in it, but I think it might have mentioned that the majority of the tank should be the new fuel to adjust totally to new fuel.

 

Now all that being said, I have made switches to and from E85, E10, and regular more times than I can remember over the last year, with E85 being the predominate fuel in that time. Been on E10 for the last month. There is no change in performance, fuel economy (based on the fuel used), etc since I brought the pickup home from the dealer brand new. Octane ratings of fuel have been between 87 and 100, up and down, and all around. It is possible that since I live 12 miles from town, that the pickup has more than enough time to adjust to any fuel switch. My bet is that folks who have issues do not run the vehicle long enough to allow ECM to adjust to new fuel. Do that enough times and the ECM can't figure out what engine parameters it should be running.

[SnakeEyeSS]

Just checked my mine and it says no less than 5 gallons of the different mixture fuel, and then drive no less than 5 miles.

[CRSilverado]

Not sure how E85 is going to increase power with the 6.2 engine. Unlike the 5.3 where advance is increased with E85, my 2013 6.2 table produces a reduction in advance on the Flex Fuel timing table.

[Cowpie]

A little something to muddy the waters a little. I have had access to blender pumps for the last couple of fill ups. Decided to try E30. With the blender pumps, I have option of E15, E30, or E85. I have used E85 quite a bit. But with E30, I have gotten pretty good results so far. MPG loss compared to regular is negligible, Not as wildly pronounced as going to E85. If anyone with a flex fuel engine has access to a station that has blender pump, might want to give the various blends a try and see if any of them work well in your engine. With the E30, it has shown the best value for me. The cost is around .30 less than regular, yet I get only a couple of tenths loss in mpg. With E85, the spread is close to 4 mpg loss. On a cost per mile basis, the E30 is at the best value for me at current prices.

 

On one level it is great to have so many choices, on another, it just makes things more complicated. I get the pep of E85, at an mpg level that is closer to using regular. It might provide a great middle option for those that have access to a blender pump at a station.