Get back on topic and drop the insults.

 

just got back from camping. pulled my 2002 keystone cougar 276 fifthwheel 240 miles each way with a fuel milage of around 8 mpg. towed at 70 mph with a strong head/cross wind both ways and seemed uphill both ways too. going up didn't downshift much from sixth but coming back went to fourth often. My brothers 06 dodge 5.9 got 8.4 towing so I was real happy with the first part of the trip. Going home he had a tail wind and got around 12 so was a little disappointed. overall I think it pulls almost as good as my old 05 Dodge cummins. Scales showed me 2000 under max weight but 400 over rear axle. love the truck and am happy with the change.

happy with the air bags too.

 

After reading thru the thread, I didnt see much on what octane the motor is suppose to run on or what real world users are using?

The reason I want to know is that I have been running a F350 1 ton diesel for my needs. That has changed. Now I am thinking of switching to a 3.5 EB motor in a F150. Hearing what octane people are running in the real world has perked my interest. THANKS

 

ecoboost runs on 87 octane.

if its real hot and your are towing heavy Ford recommends premium.

 

beat me to it

 

Wow, a lot of you have no idea what you're talking about. But, THIS^ is the most correct statement of all. I tune engines and know exactly how MAP/MAF systems work. Just because you're at a higher rpm does NOT mean you'll use more fuel. Higher rpm = more torque (to an extent) which also means more hp. More hp means LESS load, LESS load = less air being digested into the engine. Less air means a smaller fuel pulse is being used in order to maintain the proper A/F ratio. Smaller fuel pulse = INCREASED mileage. So to sum that all up, you COULD be turning at 4k rpm instead of 2k and since you're making twice the torque/hp, you have half the load on the engine (all load is either vacuum or, in this case with the 3.5 EB, boost) thus resulting in better fuel mileage. The MORE vacuum, (higher negative number) the SMALLER the fuel pulse will be, and vice versa.

 

I suspect you are fairly correct in this assessment but I believe you are working with some theory as the EB does not produce twice the torque/hp at 4000 rpms as it does at 2000 rpms so you have not cut your load in half and I would suspect at 4000 rpms you are getting somewhat close to max boost and pumping a lot more air through the engine than at 2000 rpms. I understand the computer leans the engine as you reduce the acceleration ("load") requirement, reducing the fuel requirement to a point but past a certain point, the engine must use more fuel to maintain the required rpms. Some of this is dependent upon the rear gear ratio so if all trucks had the same engine and the same final drive ratio you could then make a blanket statement. Gas mileage is also dependent on how much "load" you put on the engine in terms of hauling or towing more weight. There is also the headwind/tailwind component to consider. Lots of variables in the mpg equation.

 

Definitely. I was just generalizing and using those numbers as an example. But I've found the concept is similar for all engines....or at least the ones I've tuned.

 

I wouldn't disagree with your technical expertise. Real-world gas mileage is a pretty finnicky thing and much of it is dependent on the driver's right foot. Let's face it, for a truck, the F-150 with the EB is a blast to drive and it's kinda hard not to "get on it" (at least once in a while)...especially when it's new. The throttle response is awesome, especially after my '04 5.4. I've found the instant mileage indicator in my FX4 is helping me learn to drive the truck for the best mileage. My wallet starts to hurt when the indicator bottoms out.

 

Well guys, I've still got the dealer plates on my truck, took my truck to get the 1,500 mile oil change and then took it off road. I was happy with the ride and how easy it is to maneuver on tight ranch roads. Last weekend I took it up to Ft. Davis, TX through the mountains of West Texas and up some very steep grades. On the trip up it was mostly super early morning (got on the road at 4:30 a.m.) so I was restricted to 65mph up until probably Jourdantan, TX where I was then able to drive 70 up until I-10 where it turns into 80mph and stays that way. Before I got to the mountains my average mpg was about 20mpg and that was me (340lbs) the fiance (won't tell you her weight but know it's nowhere near me) plus all of our gear in the back seat and a 140qt. ice chest with 75lbs of ice and food and drink. Once we got into the mountains the mpg started to drop off somewhat but not as much as you'd suspect. We filled up in Sanderson, TX (look on the map and see how far it is from Corpus Christi, TX to Sanderson, TX and you'll see we ate up some ground before our first fill up) and then rode on into Ft. Davis to Prude Ranch where we stayed. We then drove up a mountain to the McDonald Observatory, back down and to Marfa, TX where we filled up (you never want to go below a half a tank in West Texas) and drove back to Ft. Davis and then to Alpine, TX and back. The next day we left and went to Balmorhea, TX on to Sonora, TX to view the Sonora Caverns where we gassed up again (btw, it's 80mph for the vast majority of this leg) drove on to Kerrville, TX and all the way back to Corpus Christi, TX on that last tank of gas. Going off of what the computer told me, I used right around 70 gallons of gas and averaged 18.2 mpg for the entire trip. Average ambient temperature for the trip was hot enough to fry an egg during the day and chilly enough at night that a lesser person might need to wear a light jacket. All in all, I'd say I'm pretty impressed thus far. Now my odometer reads right around 3,800 miles. Hope this helps someone out.

 

mine now has 2000 miles on it.

I cannot for the life of me get better than about 17 highway.

super crew, 4x4, 3.55 rear

 

It might just be your driving habits, I have a similar rig to yours, super crew 4x4 off road with the 3.73 rear end. I was very meticulous about not going over 2,000 rpm for the first 1,500 miles. Don't know if that has much to do with it, but I've got good mileage out of mine.

 

How good? Anything above 20 and i'd be plum happy

 

Supercrew, 6.5 bed, 3.55 axle. 1,350 miles showing on the odometer. I drove from Reno to the California central coast, up and down hilly Hwy 101, towed a bassboat 40 miles in the hills and then back over the Sierra to Reno. I usually drove 3 MPH over the limit (80 miles in a 70 MPH area. Total fuel average for the entire trip is 18.6 MPG.

 

Good info. Thanks!