We've ordered a new 2017 F350 with the 6.2L V8, and I've downloaded the 642-page OM for some light reading. I found this interesting li'l blurb on page 184:

I found para #3 above to be rather interesting. Without meaning to start another one of the usual fuel grade wars, have any of you 6.2L V8 owners tried higher-than-"regular" 87 AKI fuel (i.e., 89, 91, or 93) and noticed any difference in performance (i.e., fuel economy, engine response while towing, etc.)?

Thanks!
Jim / crewzer

 

I sure do see that erroneous E85 a lot. Its not 85% ethanol. Its 85% gasoline and 15% ethanol.

 

I think I will try it for a few tanks. I tried it on my 2016 but I ran the 91 octane tune from 5star too. On that truck, I did not see any mpg gain or loss.

 

Ummm...no. E85 is high ethanol blended fuel containing 51-83% ethanol depending on location and season. It's use requires a "flex-fuel" vehicle and isn't typically compatible with older vehicles. The normal at most pumps nowadays is E10 which has no more than 10% ethanol (by volume) and is compatible with older vehicles, although some tend to run poorly on it compared to actual gas (E0)

More info from the US Department of Energy if you'd care to learn more about E85.

Alternative Fuels Data Center: E85 Specification

 

Jim, when towing I use ethanol free 91 octane (that's the highest octance you get at my elevation) and I've used it as well as E10 85 octane (regular grade at my elevation) and the truck is definitely happier with the 91 when pulling a 12k lb trailer. Empty I can't tell a difference in economy nor performance, but loaded I get slightly better economy based on my tests running the same haul with both fuels.

 

Thanks gstanfield I stand corrected. Unbelievable.

 

I didn't believe it at first either. I ended up almost walking because I was traveling across country and grabbed the yellow hose by mistake (we don't have E85 where I live). A few miles down the road my truck was running horrible, thought I had gotten bad fuel. I guess I did get bad fuel, at least compared to what my 87 F250 300-6 was designed to run on! Luckily I had only filled one tank so I switched tanks and it started running good again. When I learned what had happened I looked into it more and was blown away that someone decided to use corn for running cars. Where I come from Corn is made for drinking, not running engines!

I won't get into the political aspects of it, but if you do some research on the whole E85 thing it's hard to understand, at least to me. I'll just leave it at that.


Oh yeah, it wasn't my intent to correct you from the standpoint of "you're wrong, I'm right". I just wanted to share the info since it's a new concept to many of us outside the corn belt.

 

The bit about higher octane 91 etc is not in my manual...maybe that is how they have the higher torque numbers for 2017....different tune to take advantage of the higher octane along with other tweaks...like cam changes.

Good point for more discussion.

 

Anytime I've filled up with E85, the ethanol content shows between 50 and 60% on the scangauge...presumably due to the gas left in the tank and the % of ethanol in the "E85". It gets *****ty mileage on E85 I will say.

I have run with a tank of 93 in the heat of summer and it's noticeably better taking off. With 87 and high temps, talking mid-high 90's, I can tell it pulls timing when taking off from a stop with part throttle by the sudden change in intake sound and throttle response. I also notice the idle kicks up at a stop when outdoor temps are high.

 

how are you reading that on the scangauge? xcode?

 

I've learned a lot in this thread. Im guessing I need to keep it out of anything with carburetors. Like my 80 bronco and 90 Johnson outboard.

 

Absolutely! It does bad things to the old rubber too, like your fuel lines, o-rings in the carb (some carbs have o-rings), rubber tip of the needle valve, etc. It also burns with about 30% less energy so it has to run much richer to accomplish the same performance (hence the lower fuel economy with E85)

The upsides is the really high octane of corn which means a performance engine designed to run on it will make some serious power, but use a ton more fuel doing it.

 

I don't have a 17 but to get the max power gain means I have to burn 91 octane for 40 to 60 cents a gallon more I will vote with my pocket book and run 87 octane.

I have run E85, E10 and straight gas in mine, E85 would be my last option when towing but empty I didn't notice that much difference. I couldn't tell any difference between E10 and straight gas both mileage and power when pulling or empty, my empty is 8700lbs.

I've run a lot of 85 octane in high altitudes and I can tell no difference from the 87 that I had in my tank from the low lands, I think it actually runs a little better but be sure to run it all out of the tank before you drop down in altitude. One time a wrong turn was made and we dropped down to 900ft after being 7 to 8K for a month and it ran fine but with reduced power, I just topped off with higher octane and all was fine but we also went back up to 8K feet shortly after that.

Denny

 

Thanks for the comments, Gents!

Our '00 F250's (described in signature below) everyday diet is 87, but it runs better on 89 at low- to mid-elevations (i.e., less AT gear-hunting while climbing). I've not noticed any difference in fuel economy between the two grades.

We've used the '00 F250 for a fair amount of traveling and towing in CO, MT, NW, and WY. I always used 87 AKI at higher elevations, and the old truck ran fine up to ~8K feet (i.e., US287 between Ft. Collins and Laramie, one of my favorite drives). However, I've taken it across the Togwotee Pass (~9, 700 ft) in NW WY a couple of times, and performance was noticeably reduced.

I'm looking forward to experimenting with various combinations of fuel AKI, loads, ambient temperature, grade direction, and elevation.

Thanks again,
Jim / crewzer

 

You will find that there is a big difference with the way the newer gas trucks handle the elevation, there was a big difference between my 2000 V10 and my 2013 6.2.

Denny