2014+ Tune and E85

zach1990 · December 10, 2017

Hi all. Recently purchased my first flex fuel vehicle, a 2014 Silverado 5.3 and purchased a Diablo Predator 2 for it. I'm wanting to try E85 in it and I'm curious if anyone has done so with the mentioned programmer and what your results were.

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FWIW the tuner should be here Tuesday. Have not had a chance to play with it yet.

KARNUT · December 10, 2017

My 14 was the first truck that I put a can tune in (hypertec this time) that I left the performance tune out. The reason was I wanted to be able to switch between E-85 and reg gas. Just running E-85 locally and reg on trips. It ran so well on E-85 with a little tweaking on the transmission I didn’t want to mess with the engine tune.

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Sierra706 · December 10, 2017

The truck will sense the E85 and adjust timing accordingly from the factory.

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zach1990 · December 11, 2017

Thanks for the input guys

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cbrsilv15 · December 11, 2017

My last 3 trucks have been e85, and I've never run it....

I need to try it out sometime.

Zasker1 · December 20, 2017

I have a black bear tune and run almost exclusively 85 and it is night and day between pump gas and E85 the E85 alone is a 30 or 35 horsepower pump across the entire Power Band with the black bear tune actually gnats but you certainly feel it more so on your second tank of E85 than your first

You will likely give up 3 to 4 MPG but who cares

zach1990 · December 20, 2017

I have a black bear tune and run almost exclusively 85 and it is night and day between pump gas and E85 the E85 alone is a 30 or 35 horsepower pump across the entire Power Band with the black bear tune actually gnats but you certainly feel it more so on your second tank of E85 than your first

You will likely give up 3 to 4 MPG but who cares

Was the truck tuned for E85 or 91-93?

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Zasker1 · December 20, 2017

91-93

But I have run E85 almost exclusively for the last 15000 miles

zach1990 · December 20, 2017

Good to know. Gonna have to try it out. Thanks

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lschafroth · April 25, 2018

I have 118,000 miles on my 2015 GMC Sierra All-Terrain. I can say I have not use more than 20 tanks of regular fuel. Almost 95% E85. The cost per gallon is much cheaper with E85. Yes I fill up more often but even if I get 5-8mpg better with regular fuel it still comes out way cheaper with E85.

The factory tune for E85 is amazing. You can certainly feel the jump to 380hp and 419ft lbs of torque. The Transmission goes into a "Sport mode" and is smooth and very quick.

I also have a Lewtune for 89 and 93 octane. Even with 93 octane the Lewtune is still a little sluggish at times and the shifting still isnt as quick as the stock E85. However, I HIGHLY recommend a LewTune if you are a regular fuel driver. Great support, great tune.

Lew uses the Diablo E85 tune in his custom tunes so I have the best of both. I can switch between fuel types and keep the same performance for the most part.

On days with no wind or some tail wind I can almost hit 20mpg with E85 which I never thought possible. I average 22.3mpg with peaks of 24.8mpg with regular fuel and the LewTune. Must have no wind or a tail wind to get those numbers. Average for E85 is 15-18mpg with some wind which I find acceptable.

E85 is amazing in this truck stock, even better with a LewTune.

Lannie

swathdiver · April 25, 2018

E85 is like running cheap race gas, the motors just plain love it. They idle smoother, run cooler, make more horsepower and burn cleaner which is good for the combustion chambers on the Gen III and Gen IV motors.

My factory E85 ratings are 11 city and 14 highway and mine gets slightly better than that. By the third tank, the alcohol content is highest and stable even when filling up with the idiot light on. Remember to drive at least seven miles after fueling for the alcohol content to get figured out by the computer and stabilize.

14Z71TricKed · June 12, 2021

So where is the tune file for this i too have a 14 gmc 5.3l. is anyone willing to share thier E85 tune .hpt with me?

CamGTP · June 12, 2021

Tune file for what though?

If your truck is a 2014 they should already have a E85 sensor in the hard line on the frame. So you'd just have to alter your stock tune to better suit running E85. There are ways to make it better with leaner fuel mixtures, timing changes and so on.