Better gas milage

Since this is my first post, I figured I would try to make it helpful. (Fair warning, this is just my experience, and I know that there are many factors effecting fuel milage.)

My 2012 TRD Offroad seems to get better milage on fuel WITH ethanol than without. My 2.5L four pot car got better milage when I ran ethanol free fuel, so since I bought the truck in Feb, I've been putting non-ethanol fuel in it. The other day, I put straight high test in it and saw a small increase in mpg. I'm not talking anything major, but with fuel costs what they are and money being tight for most, it's worth saving a few bucks wherever you can. If nothing else it gives you a bit more cash to spend making your truck your own.

So, if you run the 4.0L V6, and have been running non-ethanol, give regular fuel a shot and see if helps. Worth a shot, right?

 

How have you determined this? Ethonal is an oxygenator, thus requiring more fuel to keep the proper a/f ratio. Many many hours of research has resulted in 90% of sources saying E-10 provides less mpg.

 

E-10 has less energy than pure gasoline, but it is harder to burn and resists detonation. The 4.0 retards the ignition timing when knocking is detected (from regular 87 pure gas), and advances it when there is no knocking.

The actual loss in fuel efficiency for E-10 is far less than most people report. Usually, E-10 is associated with winter gas, which is less efficient because it has a much higher proportion of butane relative to longer carbon chains in order to have a higher vapor pressure and be more easy to burn than summer gas. This false association leads people to believe that E-10 will have about a 10% drop in fuel economy. For this to be the case, it would have to store precisely ZERO energy. In reality, it stores 90% as much energy as pure gas, so E-10 stores 99% as much energy as pure gas.

If retarding the timing causes a 4% loss (for example), than E-10 could easily yield lower fuel consumption.

 

My 2012 DC OR (4300 miles on the odometer) is averaging 19mpg. Every fill up with E0 87 octane has yielded 20.3 or better mpg. The best mileage running E10 has been 19.5mpg with the worst being 17.9.

 

The stoich ratio of ethanol is a lower number than that of gasoline. It's 9:1 instead of 14.7:1. (see http://ethanolpro.tripod.com/id213.html)

IIRC the stoich ratio of E-10 is 14.0:1. That means it takes 5% more fuel mass to run E-10 than straight gas under cruising conditions.

Maybe the ethanol-free fuel you were getting was lower octane stuff... the V6 tends to like some knock resistance so that could explain your mileage difference.