Some initial results using E85 in the 2014 Silverado 5.3L.

Note that the truck is brand new and only has 1000 miles on it. So far with gasoline I drove the same 124 mostly highway route back and forth 6 times. 5 using gasoline and 1 using E85.

On gasoline I averaged 19.2 MPG
On E85 I averaged 17.9 MPG

Gasoline contains 114,100 BTU'* per gallon while E85 only contains 76,100 BTU'* or approx. 33% less energy. However, the cost of E85 in Michigan is $2.89 vs. $3.61 for gasoline or approx. 25% less. Additionally, the EcoTec3 motor in the Silverado has 355 HP on gas but 380 on E85 and 383 torque with gas but 416 torque on E85. So 25 more HP and 33 more torque.

Also, the EcoTec3 motor features cylinder deactivation which allows it to run on 4 cylinders instead of 8 when under low load.

So if the gas MPG is 19.2, E85 will need to get only 14.8 mpg for the same cost per mile (18.8 cents per mile). With the E85 MPG of 17.9 it is costs 16.1 cents per mile or approx. or 14% less than running on gasoline.

I suspect the added HP & Torque due to the higher compression ratio allows the truck to run in V4 mode a little more making up for the lower energy in E85.

Stay tuned for more results in the future including tests when towing!

thats the first time i heard anyone say that. my 07 3500 monte went down 30% with e85. and e85 here was 3.10-3.20 and gas was around 3.80

Without cylinder deactivation, CVVT, and direct injection E85 is a waste of money.

your engine has the same efficiency on gas or e85, but the e85 has 30% less energy. so you use 30% more fuel to produce the same amount of power it takes to push the same vehicle through the air. you are not using 350hp at cruise on the hwy, probably more like 40-50.