I average about 20mpg on E-85

 

City, highway or mix of both?

Anything special in your tuning that helped you achieve that, like bumping the timing tables etc...?

 

Nothing special in the tune, a mixture of both highway/city. Elevation where I'm at everyday varies between 4800-11000ft so lots of going uphill and downhill.

 

on highways i got as high as 300miles so probably 22-23. afr cruise is 16 when i did this.

 

That's 20mpg.

- Bryan

 

How is that?

 

With 80% highway driving miles I am getting around 18.7 mpg. But city I'm getting 14.7-15.9 mpg.

I'm going to try changing my driving habit for city. I was keeping rpms low for acceleration and cruise. I'm going to try bumping the rpms and see if that helps, higher rpms less load. I'm thinking maybe my tune has better timing for higher rpms than lower.

 

Time for me to look at my driving habits and maybe get my tuner to lean it out under cruising conditions. My first full tank ended up as 14mpg. This was city/hwy mixed but very little WOT so I thought it might be more like 16-17.

 

Food for thought- each tune will have a bit different best mpg drive technique. On most factory ffvs I find I want to avoid multiple cold starts such as starting up- going less than a mile to a c-store for coffee and then restarting- especially in cold weather. This results in two cold start enrichment events. I do far better to wait until the engine reaches full operating temp for the first stop. Never idle on E85-especially at cold start- not enough heat is generated. Short trips (<3 mile) are a real penalty on E85. All of these type of drive cycles hit gasoline mileage hard too-but it is really magnified on E85 due to the cold burn properties of E85. The worst application for E85 is when the little old lady who lives a mile from her hairdresser, the grocery, and her church buys a 8 cyl FFV pickup. Now you guys are not like that but something to keep in mind.

I drive 35 miles per drive cycle, mostly 2 lane country hwy, with a couple of small towns to go thru and normally see a range of 78% to 82% distance on E85 vs gas with Ford and Impala FFVs. My son's S10 runs at 88%-84% distance on E85 vs gas but it is a fast warming 4 cyl and with a real ethanol sensor (vs algorithm of the other FFvs). The new 2L turbo Buick FFV is supposed to operate at a reduced range of less than 10%-- we will see if that is true once people buy them and run 'em on E85. This was not true of the Saab version where the similar version was port fuel injected (instead of DI) and Saab was going for raw hp gains of +20-25% on E85 (via added boost on E85)- they drank more like all current FFV models from what little I have seen for info coming out of Europe.

Not sure how any of this applies to what you guys are doing

 

still getting the same mileage over a year later

 

I'm getting 17mpg on E85 right now but that is with the occasional "show the slow pokes how it's done".

$2.60 a gallon E85 x 4 gallons = $10.40 | 17mpg | 68 tmd
$3.29 a gallon 93o x 4 gallons = $13.16 | 21mpg | 84 tmd
16 miles lost vs 93.

$13.16 - $10.40 = $2.76.
So I'm at break even on gas but I'm +40hp at the wheels yay!

*update, I leaned out my high oct map from 2k to 3.5k on 10/20/30 load so
I have a 15.2 to 16.0 afr (down from 14.x) and over the last two
tanks I got 19mpg.

Now E85 is winning