Run a tank of E85 orleave well enough alone ?

[belair62]

2011 5.3 flex hasn't run E85 in a couple years. Was thinking of throwing a half tank in as a cleaning agent. Truck runs perfect now. Should I throw the dice or leave it the hell alone ?

 

[opfor2]

I was wondering about doing the same thing.

 

[Marky Dissod]

I've only ever used E85 under the following conditions:
1. It's at least 25% cheaper than E10 or 30% cheaper than pure gasoline
2. ALL the E85 was absolutely gonna get used up that same day
3. also use a bottle of Chevron w/ TechRon in the same tank
4. No more than half a tank of E85 at most (13 gallons for Tahoes)

Don't like storing E85 in my gastank for more than a day, it'll pull moisture from air and then push it through the fuel pump.
If E85 isn't cheap enough, it's not worth the MpG sacrifice

 

[mikez71]

wow did not know it would pull moisture so fast.

FWIW I put in a couple full tanks lately and it runs as good as ever, although i only get 8mpg (all city, get 11.5 normally)

 

[Charlie207]

Do you notice any bump in power?

 

[Marky Dissod]

I've no problem with using E85 if it's cheap enough, only with NOT using it up quickly.
And it's almost never an arid day in NYC ...

 

[j91z28d1]

wow did not know it would pull moisture so fast.

FWIW I put in a couple full tanks lately and it runs as good as ever, although i only get 8mpg (all city, get 11.5 normally)

I mean it would absorb water if left in a open bucket. but a sealed fuel tank in a truck that's listed as flex fuel. not something I'd worry about and even if it did suck up water, as long as we can trust gm to use ethanol safe fuel system parts in their flex vehicles, it wouldn't add any corrosion and water would just be water injection. which also cleans carbon really well. we used to decarbon old Ford straight 6 engine by blocking off the radiator till they get about 260, Rev them up and pour water down the carb. took about a gallon or so and like magic, clean tops of pistons. rebuild the carb that caused the carbon knock on the first place and send it on its way. engine would outlast the equipment.

I used to run some e85 thru my no flex car every once on a while to clean it up, then I'd follow the don't go 100% and try to use it the same day or so. but without any tuning don't run in PE mode. which is above like 70% throttle on most cars. the high octane is pretty forgiving even if you run it a bit lean thou. that car ran flawless for over 100k of pure abuse till it got stolen in Nola. and even a year or so later when it was recovered it still sounded perfect. sadly they wouldn't let me buy it back for the drivetrain.

my yukon is a non flex and I keep meaning to grab some e85 to clean up some carbon I saw with a bore scope while doing plugs. wasn't bad, but couldn't hurt, just haven't yet.

 

[j91z28d1]

wow did not know it would pull moisture so fast.

FWIW I put in a couple full tanks lately and it runs as good as ever, although i only get 8mpg (all city, get 11.5 normally)

if you had access to the e85 timing tables to add a few deg and clean up the fueling a bit. it would probably almost match what you get on say 87.

I've got friends deep into the e85 stuff in German cars and with a little bit of clean up they get same or better mileage from e. but their factory ecm's also run full wideband closed loop control and direct injection. they ran crazy numbers that don't make sense in my ls based world haha.

 

[Marky Dissod]

Do you notice any bump in power?

Tough to measure the extra power.
Quicker throttle response is definitely obvious, but since traffic has been made worse with all the extra bike lanes, there's almost never enough room to enjoy it.

 

[belair62]

Thanks all. I just read where this virtual ethanol sensing gets screwed up and then boom it runs like crap on regular gas and you need a scan tool to correct it. I feel like there is always a bomb waiting to go off on this thing.

 

[intheburbs]

No.

The only time I run E85 is when I'm on a road trip and I'll be burning the entire tank. Not gonna let that shit sit in my tank.

 

[petethepug]

We’ve run it 24/7 for over two years since we found it local. Milage drops in town about 20%. Highway milage maybe 5-10% less milage. Overall e85 gives our 30gal 6.2L about 225 mi per tank local. On trips about 250/60 mi per tank.

It’s literally 1/2 the cost of our 91 and at least 100 octane. It idles the motor like it’s electric and hits the downshifts quicker. The oil stays cleaner longer and leaves no carbon deposits in the combustion chambers.

I change out my e85 by driving the vehicle til almost empty every 8-12 days. Both the e85 and the brake fluid are hygroscopic but the e85 gets changed much more frequently. I’ll, of course, report in if there’s issues with it.

 

[mikez71]

I can't say I notice a power increase, but have been conservative on the throttle.
Being it's 100 octane, I hope it won't trigger knock retard, whereas before I have logged upto 5 degrees of knock retard on 91 octance.
Mainly ran it just to test it out, heard it keeps the motor cleaner. It is cheaper despite the reduced mileage. Roughly 60% the cost while getting 85% of the mileage

 

[Vladimir2306]

When I traveled around Europe, I constantly poured E85. It's twice the price of petrol. Drove a lot on it. There were no problems with it, except that fuel consumption increased by about 10%, and there was a feeling of a decrease in power. But nothing critical. And so the periodic use of E85 is an excellent tool to remove water from the tank. In Russia, unfortunately, there is no E85. Because we have introduced a minimum cost of ethyl alcohol of about $ 1, while Gasoline costs about $ 0.6. So we have no point in E85 fuel. And that would be cool.)

 

[Marky Dissod]

It’s literally 1/2 the cost of our 91 and at least 100 octane.
It idles the motor like it’s electric and hits the downshifts quicker.
The oil stays cleaner longer and leaves no carbon deposits in the combustion chambers.

If it keeps the engine cleaner, as you say, then I'll need to find cheaper E85 - which may not be possible in the 5 boros of NYC.

 

[belair62]

Itsalmost a dollar cheaper in Chicago

 

[wjburken]

In Iowa, it is heavily subdivided by the state so it is usually significantly cheaper per gallon. The only thing is when you get E85 at the pump, it can be anywhere between 50% and 85%. It just depends on what’s in the tanker truck.

 

[Fless]

I run it almost exclusively in my L59, although I do have the physical alcohol sensor. My local station is pretty consistent at around 68% alcohol. Runs around $0.70 to $1 less than regular (85), and a lot lower than 91 (which is our premium).

I don't have any problem with it sitting in the tank, mine sits for a week or two at a time.

 

[swathdiver]

2011 5.3 flex hasn't run E85 in a couple years. Was thinking of throwing a half tank in as a cleaning agent. Truck runs perfect now. Should I throw the dice or leave it the hell alone ?

I was wondering about doing the same thing.

If you guys have fairly new OE oxygen sensors (under 100K miles), run it! If they are old or aftermarket, they might screw up the virtual calculation and may cause driving issues or may not.

E85 is like cheap race gas, the motors love it! Put 5-6 tanks through the motor and the computers will fully adjust for it, even the transmission runs better in ours on that stuff.

There are no issues leaving it in your tank for a time, I've sat parked with only 5 gallons in the tank for over a month many times without issue. We have plastic tanks and everything else is made to come in contact with it in our fuel system.

It is an excellent cleanser so if that's what you want to do, who cares how much it costs. That's not the reason you're running it.

Driving around town and out to about a 50/50 mix of city and highway driving the 5.3 will burn a 1/2 gallon more per hour on E85 than 93 octane gasoline. On the highway, about a gallon more per hour.

These are my truck's stats since late 2017 and 220+ fill ups:

 

[belair62]

If you guys have fairly new OE oxygen sensors (under 100K miles), run it! If they are old or aftermarket, they might screw up the virtual calculation and may cause driving issues or may not.

E85 is like cheap race gas, the motors love it! Put 5-6 tanks through the motor and the computers will fully adjust for it, even the transmission runs better in ours on that stuff.

There are no issues leaving it in your tank for a time, I've sat parked with only 5 gallons in the tank for over a month many times without issue. We have plastic tanks and everything else is made to come in contact with it in our fuel system.

It is an excellent cleanser so if that's what you want to do, who cares how much it costs. That's not the reason you're running it.

Driving around town and out to about a 50/50 mix of city and highway driving the 5.3 will burn a 1/2 gallon more per hour on E85 than 93 octane gasoline. On the highway, about a gallon more per hour.

These are my truck's stats since late 2017 and 220+ fill ups:

View attachment 401996

This is great info thanks. P.O. Put new cats and o2's in mine but not sure what brand he used. He is a BMW tech so hopefully he used decent stuff. Im gonna put a half tak in tomorrow and see what happens.

"EDIT" Just talked to previous owner. He thinks he used Denso or something other than OE