14.7 MPG Highway - 17.7 MPG City....How??

If frictionless bearings, it will use exactly, precisely the same amount of fuel at constant speed on the highway in both cases. The drag force is the dominant force that the vehicle is overcoming to maintain constant speed. The rolling resistance is a tiny, tiny factor compared to the aero drag force at 70 mph.

I am assuming if you are on a 9 hour trip, you are setting the cruise control and leaving it alone. If you aren't, you're doing it wrong.

Hopefully not doing a lot of accelerating from stop on the highway. The mass comes into play in the city when you are stopping fifty times at stoplights.

Looks like most of Kentucky is pretty hilly for sure. You get it back going down the far side of the hill though?

For sure. I think the Prinsu roof rack he mentions in his profile is the biggest problem, followed by the lift implied by the "OME" which I think is a spring kit that raises the vehicle by 75 mm or so. I don't think the bumper is going to make much difference on the highway.

 

You don't get it back going down the hill lol. If that were the case, then we would have perpetual motion...

 

Will you not get back just about all the potential energy you put into the truck by climbing the hill?

 

We talking green valve stem caps or black ones?

 

Wait, are we talking about the real world, or physics class?

 

What was the wind doing during the trip? 70+mph lowers the MPG on a stock truck in clam winds. I've seen 16mpg at 70 with a 20mph headwind in the winter with my stock truck. Essentially getting the same drag as going 90mph. Air is denser in the winter too. Aero sucks on these truck, even stock.

One of the biggies for Aero on your truck has to the the upper light bar. That is an area of pretty high pressure and its going to cause more separation over the roof and down the back of the truck.

Edit: My normal commute at 65mph usually nets me 19+ MPG winter and 22+ MPG summer. Iowa typically has pretty stiff winds in the winter, and much calmer in the summer.

 

Still can...

 

Sounds about right to me lol wooooo woooooo chuga chuga chuga

 

Do you speed up or maintain it?

 

Yes and colder temperatures have nothing to do with mpgs too.

 

Your highway MPGs are gonna be low cause the truck is shifting constantly to maintain speed, plus youre trying to thread a lifted 5k lbs vehicle down the road. These don't handle the weight well in the MPG department, but then again why look for mpg improvement after adding tons of crap. Im lifted with bigger tires and some extra add-ons and get 17-22. With ECT on, I get an easy 4mpg less across the board, so if that's on youll take a big hit. Also adding a ton of weight to a V6 or any kills MPG from the rip. Like with the Jeep its, Smiles per gallon, not miles per gallon.

 

I just did a 500+ mile round trip from KC to Great Bend, KS. All my previous trips this summer I got 20-21 MPG at 65-70 MPH. Fighting a headwind on the way out this weekend I got 17.5 MPG at 65-70 MPH and I got 15.5 MPG on the trip home at 70-75 MPH. The truck is not fuel efficient at all over 70 MPH in my experience. It just sucks the gas down. But I attribute most of the drop in mileage to winter blend gas.

 

I drive the Ferndale, Montverd area every day in lake county, Florida. It has some steep hills and massive curves. With my stock tires (245 75 16), I still averaged 23 to 24 mpg. Since, I put on 265 75 16 and lost about 2 mpg. Not only are these heavier and wider tires, I find that I have to give it more gas to climb the hills and rev up after the S-curves. I took a hit. I knew I would. And I’m cool with it. And if and when I decide to add more weight, I’m going to lose more mpg’s.

That’s the way the baby buggy bounces.

 

Am I the only one whose mileage goes up very consistently in the winter (at least on my commuter car where it's easy to track)?
(No AC used, and probably drive a bit slower due to all damn snowbirds clogging the roads I assume)

[BTW, I also like Publix cake... could go for some marble with whipped topping right now]

 

Man, your area has nothing on mine!! I live in the Leesburg area. Can you say the villages!!! Lol

 

Absolutely 100% agree..

 

It does, but people don't say "denser air, warming time of the engine, driving habits, and increased rolling resistance" caused their bad MPGs. It is always the gasoline's fault.

Besides, the guy I was responding to later said he lives in a warm area.

 

Potential Energy and the gasoline consumption of the vehicle are not the same thing.

The laws of physics regarding the Conservation of Energy dictate that you can not break even by going back down the hill after the climb to the peak. If you coasted down a 100 foot hill and then attempted to coast up a 100 foot hill you would not make it to the same vertical elevation. There is ALWAYS a loss. A very simple example of this is a roller coaster. No peak on a roller coaster is as high as the first peak.

It obviously takes *less* fuel (energy input) to get down the hill than to get up it, but there will *always* be a net loss and it will never 'even out'.

 

Longer start up times and efficiency are the reasons for worse gas mileage in the winter. "winter gas" has very little effect, its likely due to the below freezing temps causing the engine to be less efficient. The same goes for altitude.

 

Haha same. On a recently trip back from the in laws i was just ready to get home so was going >80 the whole time and was getting 15.5 at best on the highway.