Towing on E85, can't recommend

Brian S. · October 6, 2014

I made the 200 miles trip up North for one last fishing trip, tried straight E85 with my 4.3l 4X4 Z71 Xcab.

Night and day difference, but for the worse.

On E85, I was in a lower gear pulling 3000 RPMs a lot. I also got 8.3 mpg, not good.

I filled up with no ethanol when I got down to 1/4 tank, and then with E10 before coming back.

11.4 mpg (usual) and held it between 1700-2100RPMs most of the trip, including a lot of the hills.

So whatever makes E85 great for driving around unloaded does not carry through to towing a 2500lb boat.

kstruckcountry · October 6, 2014

Technically it should give you more power. If I was towing anything significant though, I'd click 'er down to 4th. I've found spinning 3000 rpm with a load is actually a good thing though, at least in my old pickup. It never has to shift, the trans stays cool and it gets better mileage that way.

All that said I hate ethanol, and I run 100% pure dino juice.

Brian S. · October 6, 2014

Technically it should give you more power. If I was towing anything significant though, I'd click 'er down to 4th. I've found spinning 3000 rpm with a load is actually a good thing though, at least in my old pickup. It never has to shift, the trans stays cool and it gets better mileage that way.

All that said I hate ethanol, and I run 100% pure dino juice.

That's why I wanted to try it- because you can feel the additional torque it gives when driving unloaded/not towing.

I was pretty surprised when the engine seemed to be working harder, seemed counter intuitive.

Definitely towed my 2000lb boat +gear and trailer much better on gas, and much cheaper.

Higgs Boson · October 14, 2014

Let me ask you a question.

What city did you start in and what city did you travel to?

Brian S. · October 15, 2014

Let me ask you a question.

What city did you start in and what city did you travel to?

Madison,WI to Eagle River,WI.

Yes, I went up 800' in elevation, but I've made the trip on E10 with the truck holding the 1700-2100 RPMs I'M used to with 2010 and prior 5.3s.

KARNUT · October 15, 2014

It should make more power, while using more fuel. The load shouldn't matter.

thefishhawk · October 15, 2014

yeah, you are going to see a 30%+ decrease in mileage with E85 even without towing a load. If you normally get 11 then 8 is probably right. Strange that you felt less power though. The spread in prices needs to be enough to cover the mileage drop to make it cost effective unless you just want it for the boost.

Crooks · October 19, 2014

I agree with opening post. With an empty single axle trailer my average was 8mpg and the truck wouldnt shift into OD. I am going to try and burn through this half tank and what reg e10 gets.

Brian S. · October 19, 2014

I agree with opening post. With an empty single axle trailer my average was 8mpg and the truck wouldnt shift into OD. I am going to try and burn through this half tank and what reg e10 gets.

At 8mpg, the "worse mileage" takes on a whole new meaning. They don't sell E85 at most stations, so you definitely have to stop more, plan better.

Not worth it for me, but the experiment was worth trying.

bdbake01 · October 20, 2014

I agree with opening post. With an empty single axle trailer my average was 8mpg and the truck wouldnt shift into OD. I am going to try and burn through this half tank and what reg e10 gets.

I must be missing something here. 8 mpg (on E85, sure) and no OD on an empty single axle trailer??? Were you dragging the brakes or something?

Crooks · October 21, 2014

Why would I drag the brakes? The trailer didnt even have brakes.

unloaded 70-75mph

On the way back with a lawn mower on I got 10.5mpg on DIC with half e85 half 91 octane at 80mph

Crooks · October 21, 2014

Just bought an e85 tester. Maybe I am getting bad corn.

Brian S. · October 21, 2014

Just bought an e85 tester. Maybe I am getting bad corn.

I spoke to one of my friends about this, he advanced an interesting theory.

Maybe the E85 runs the engine at higher RPMs/lower gears unloaded as well, and that is why it feels snappier and gets worse mileage, but you don't notice because running at higher RPMs unloaded isn't as noticeable as towing.

So if you're normally cruising around at 1700RPMs and it does 2100 RPMs on E85, it would feel like you were getting more instant throttle response. But if your normal RPMs towing on E10 keep you below the point it shifts to the 3000 RPM gear, adding a few hundred might kick it over to the lower gear and keep it at the 3000 like I saw.

I'm guessing running it on a 5.3l would not be the same, it's just that the 4.3l is closer to the programmed shift points because the smaller engine has to work harder pulling the load.

I've towed more on E10 since, and I would say the only thing I miss about my 2010 5.3l is the transmission cooler. Even though I know the temps I'm getting (205-210) are well below the synthetic fluid's capability, I'm old school and have a hard time getting past the "no external cooler" on a truck.

bdbake01 · October 21, 2014

Why would I drag the brakes? The trailer didnt even have brakes.

unloaded 70-75mph

On the way back with a lawn mower on I got 10.5mpg on DIC with half e85 half 91 octane at 80mph

That was kinda my point, which is "What could be causing such up realistically low mpg's", but I think I see the problem now:

-Leveled truck

-Single axle trailer WITH a huge wind catcher in the worst spot (aerodynamically speaking, it is handy for getting stuff off the trailer)

-E85's inherently lower mpg

Add all that up, there you go.