Okay bare with me on this response, but this will clear up a lot of good questions that were posed.
Seems like you are getting pretty good mileage. I got 11.1 on my first tank with 87 octane but my commute varies in elevation by about 800 ft. I filled up with 91 this time and will see what difference it makes.
Elevation is pretty consistent, jersey is a pretty flat state. Going to work it is slightly more time spent going up minor elevations than down. Usually my readout will drop by 0.1 mpg on the way to work, and go up by 0.1 mpg on the way home from work.
Should have gotten a Prius
lol
I would like to ask for an overall question, what are your driving patterns with these numbers? Highway commuting at what speed or in town driving? I ask that because the raptor I took on a test drive I saw 16mpg on hwy at 60mph.
Mine is a mix. I've never reset the readout while cruising on the highway, I reset it every tank, for the entire tank, and do the hand calcs for the true number.
My commute is 14 miles each way, 50 mph roads, 11 stop lights, 3-4 stop signs. So it's somewhat highway speeds, but lots of stop and go's between close to 15 lights/signs, I usually always get caught at at least half of them. Then on weekends I usually do some highway driving, 65-75 mph. Along with some local around town driving on short errands. Pretty broad spectrum mix. Each tank has been the same type of driving.
thats very interesting ......guess im going to have to stop wasting time using 93 if 91 clearly is more efficient an the truck likes it better .......do you believe there's any hp difference between 91 an 93????? im getting around 10.6-10.7 mpg right now an it really dosnt bother me that much but if 91 is what the trucks running best on....or running the same as 93 sign me up man....nothing wrong with wanting whats best for my baby...... good write up!!!!!
While one may think that if 87 = 400 hp and 91 = 411 hp that 93 = 416, but even if it did work like that, honestly you're never going to feel 5 crank hp difference by the time it gets to the wheels and in a 6 klb truck no less. I'm always OCD with my vehicles though and it's usually nothing but the best, so 93 was of course my first few fill-ups, but between wanting to try what the engine was actually tuned for, and also filling with 93 I'd usually bump the $125 limit and have to run my card twice, filling with 91 I actually just made it at $124 and change so only had to run my card once LOL.
Honestly though I'd try it out if you're currently running 93 on a stock tune. It's still the higher end of the fuel rated for the truck, it can't do anything but potentially give you a tad bump on mileage and the same feel behind the wheel. I'd just advice to be aware of all the variables. Add 91 then go romping to see if you feel a power difference, you're probably going to see a mpg decrease from the driving style difference lol.
Very interesting. Thanks for posting this.
Does the fuel you use have Ethanol in it? Are you buying your fuel from the same place? I have always wondered if 87,89,or 91 octane fuel was the same from place to place as far as formulation goes.
I have noticed MPG increases in my vehicle, using fuel without Ethanol. It is hard to find in my area anymore. Most places near me have stickers on the pumps saying that their fuel has 10% Ethanol.
All our fuel in NJ is E10. So 87, 89, 91, and 93 are all 10% ethanol. And actually every one of my fillups, other than the initial tank of 87 from the dealer, was at the same station, and actually the same exact pump, and same gas attendant.
I wonder if it really does detect or if you just had break in timing changes right...Thanks for doing this experiment as while I am not worried about gas miles I certainly would want to maximize what I could...it will be interesting to figure out the cost of miles per gallon and what really does turn out to be a better value.
The 5.0 Mustang does the same thing. Has different power ratings depending on what fuel you run. I'm assuming it goes off the factory knock sensor, once it detects knock from a lower grade fuel, it pulls a tad of timing till it senses another fuel up and readjusts accordingly.
awesome detailed right up man great stuff here im gonna have to try it out cause i always put 93 in it. i actally have to get gas today i only have about 28 miles til E so im gonna put 91 in it and see how well that works out..thanks again for the information on this keep us informed on how this all goes im very interested to see how it turns out
Like I mentioned, just be aware of all the other variables that can play into it. 1/2 to 1 mpg difference can add up over time, but it can easily change 1/2 to 1 mpg just from a small change in driving habbits, driving course, etc.
You also need to remember mileage should get better as the motor breaks in .
Yep, but the increase of mpg from break-in diminishes as the miles rack up. I attribute the decent bump from the 1st tank to 2nd tank from purely that. Then the marginal jump from 2nd to 3rd to break-in as well. But every one of those tanks, it was a very slow difference on the instant readout. It would slowly improve 0.1 to 0.2 mpg a day. As soon as the switch from 93 to 91 was made, I saw an instant bump on the instant readout by nearly 1.0 mpg, leading me to believe this tank's bump is moreso from the truck's tune being more optimized for this octane, than the higher octane I was running.
And beware the summer blend, where the BTU value is higher in summer blend than winter blend.
Summer blend will soon be out (and it costs more to produce), and your gas mileage should increase.
And there a statistical issues (sample size, Gage R&R, etc.) that need to be considered with making decisions, especially on a small number of tank fulls (confidence interval) by humans at gas pumps (a multitude of variables - Gage R&R).
Another good point. I've always logged my fillups and fuel economy on previous vehicles, and I almost always see 1 mpg difference between summer and winter blends. Thats part of the reason I only plan on running 2 tanks of 93, 2 tanks of 91, 89, 87. Then I'll repeat. By the time I get around to running through a second time, we'll be on summer blend and I'll be able to get another comparison.
