Is 12 mpg an acceptable number?

[emers382]

Jim, interesting chart you linked to. Hope all realize that the mpg figures are for imperial gallons. The chart is worth only to compare mileage of one truck to another, it's certainly not real world mileage. For example our NC (moving to KS) son-in-law's F150 ecoboost at just over 20,000 miles was at 16.9 (14 l/100km) on the computer with mixed highway/city driving. The chart says for his model 14 l/100 km city and 9.6 highway.

We have had only one trip in our 5.0 through mixed flatland and northern ON Cdn. shield driving and our average dropped from the best I'd had with truck alone from 12l/100km (19.6 mpg) to 14l/100km (16.8 mpg) that is until after the last fill up when we got only 17 (13.8 mpg) into a headwind!

Adrian

[dave macrae]

Like others I will use the cruise on flat easy ground to maintain a constant speed but when apoaching a hill I kick it out as it causes a down shift long before its needed. I find that with a slight stab of the throttlle I can unlock the torque converter and increase rpm by about 200-300 rpm and roll up most hills with needing to down shift into 2nd gear. Of course on the really steep stuff that doesn't work. By the way Brian we were told that we might be getting some diesel Canyons in early spring ( 2015) but yes they will technically 2016's , much like we go the 2015 3/4 ton and 1 tons this year. The gas Canyons should be here in August of this year.

[Brian B-P]

Originally Posted by dave macrae

By the way Brian we were told that we might be getting some diesel Canyons in early spring ( 2015) but yes they will technically 2016's...

Thanks for the update.

[Brian B-P]

Back to the original question...
12 miles per US gallon is about 19 litres per 100 kilometres. That's perhaps 20% more fuel than we have used towing our trailer, which is about as wide as an Escape 21; however,

• my trailer is half a ton lighter,
• my trailer is single-axle (versus tandem),
• my van is somewhat lighter and better shaped aerodynamically, and
• my van's tires are narrower.

All of these factors will improve my fuel consumption, so Jim's 12 MPG doesn't look unreasonable to me.

[davescape]

Originally Posted by cpaharley2008

I installed a cold air intake as well as throttle body spacer for some extra hp increase to 420 vs stock 390hp.
.

.....of course for some of us, poorer mileage and long hill climbs are just pipe dreams. I'd love to compare the mileage between my stock 390 and your 420 but we're still waiting for our asphalt anchor

When I was kid my Dad had a 1970 3/4 ton Fargo with a 318 ci. I can't remember the exact mileage but I do remember his surprise that it achieved similar mileage with or without the full size camper. Weight (it was a heavy homebuilt) and frontal area had little impact.

BTW tire size can impact mileage significantly if you increase to a larger than stock diameter.

[daveandsandyclink]

Sorry Jim...12 mpg while towing would not be acceptable to me in the long haul. That's about average mpg of a much larger/heavier 24' Class C.

[gbaglo]

Originally Posted by davescape

.

BTW tire size can impact mileage significantly if you increase to a larger than stock diameter.

I decided to leave my winter tires on and wear them out before replacing them with all-weather tires. My summer tires (all-season) were on their last leg and I only have one set of rims.
Thus, my question; could that be why I seem to be getting poorer gas mileage lately?

[padlin]

It'll be interesting to see Alf's figures once he gets them worked out. One would expect going from the SA to the TA mpg will drop, same as going from a 19 to a 21.

Jim, did you ever pull your 19 with the Dodge? do you recall what you got for mpg?

[cpaharley2008]

Originally Posted by padlin

It'll be interesting to see Alf's figures once he gets them worked out. One would expect going from the SA to the TA mpg will drop, same as going from a 19 to a 21.

Jim, did you ever pull your 19 with the Dodge? do you recall what you got for mpg?

About 13 mpg with the 19' Escape, but that was not cross country, just here on Yeast coast.

[Brian B-P]

Originally Posted by gbaglo

I decided to leave my winter tires on and wear them out before replacing them with all-weather tires. My summer tires (all-season) were on their last leg and I only have one set of rims.
Thus, my question; could that be why I seem to be getting poorer gas mileage lately?

The more aggressive tread and softer rubber of winter tires could cause a small increase in fuel consumption. Width is more of an issue, but winter tires are not normally sider than the same car's summers.

Increased diameter doesn't cause higher fuel consumption, but it can seem like there is a reduction because your odometer reading is low: you underestmate how far you are going on a quantity of fuel.

[daveandsandyclink]

Jim,
Could it be the wrong gear in the rear axle? Does your truck have 4 wheel drive? What do other Dodge Hemi owners get while driving/towing?

[davescape]

Originally Posted by Brian B-P

Increased diameter doesn't cause higher fuel consumption, but it can seem like there is a reduction because your odometer reading is low: you underestmate how far you are going on a quantity of fuel.

Brian, I'd forgotten about that effect, and you're quite right. What I was thinking about was that by upsizing your tires you're effectively changing your gear ratio. I believe that most manufacturers are carefully matching the tire size and differential gear ratios on their base model vehicles to achieve the best mileage, among a few other concerns.

[Vermilye]

Over the last 3 years of towing & 48,000 miles, I've averaged just under 15 MPG US. Of course I'm cheating & pulling a 17B!

[Paul S.]

When I need new tires I will likely go with a 35" tire which is larger than the stock 33.5" and I fully expect to use more fuel. I haven't met anyone who hasn't had a drop in fuel economy because of an increase in tire size. The vehicle will sit higher, the tire will probably be heavier and the larger diamter will change the final ratio. In my case the speedo should be dead on at 100km/h with the increase. If not I'll have the Ford tech reprogram the "computer".

Back to the topic. 12 mpg isn't so bad for a hemi towing. I'm usually in the 14 mpg US range with the truck loaded with 3 dirtbikes and one quad on top of the deck and the box full of gear.

[cpaharley2008]

Originally Posted by daveandsandyclink

Jim,
Could it be the wrong gear in the rear axle? Does your truck have 4 wheel drive? What do other Dodge Hemi owners get while driving/towing?

I do have 4 wheel drive and 20" wheels/tires and a 3:55 rear end. There is a cap over the bed which should help aerodynamics. I think it is weight and just the engine, over on Ram forums and other rv forums, some people get 8-9 towing? It does have the mds which shuts down 4 cylinders and that sometimes happens while towing on a flat run and not in tow mode. Then the instant mpg increases to about 18 mpg.

[Brian B-P]

Originally Posted by davescape

What I was thinking about was that by upsizing your tires you're effectively changing your gear ratio. I believe that most manufacturers are carefully matching the tire size and differential gear ratios on their base model vehicles to achieve the best mileage, among a few other concerns.

Good point, but depending on individual driving conditions the effect of the gearing change could go either way... and it's a small change in gearing. Gearing selection is always a compromise.

Originally Posted by Paul S.

When I need new tires I will likely go with a 35" tire which is larger than the stock 33.5" and I fully expect to use more fuel. I haven't met anyone who hasn't had a drop in fuel economy because of an increase in tire size. The vehicle will sit higher, the tire will probably be heavier...

Yes, but the weight increase of reasonable tires is irrelevant compared to the vehicle weight.

[Paul S.]

A "reasonable" tire? In a truck tire it's hardly irrelevant.

[Brian B-P]

Originally Posted by Paul S.

A "reasonable" tire? In a truck tire it's hardly irrelevant.

Maybe my intent wasn'tclear in this:

Originally Posted by Brian B-P

Yes, but the weight increase of reasonable tires is irrelevant compared to the vehicle weight.

By "reasonable" variations in tires I meant approximately anything available as a factory option, or aftermarket swaps that you might not notice passing you on the street.

Beyond reasonable is stuff that looks like it belongs on an unlimited off-road competition truck. You can mount those things, just as you can swap in a monster engine or military truck axles... and in any of those cases you're probably not posting here and asking if your 12 mpg seems reasonable to other people.

Even a couple hundred pounds of extra tires (for the set of four) is just like another big passenger, and not a big deal for a truck weighing 2 or 3 tons.

[Paul S.]

You're right.

You win.

[daveandsandyclink]

When I said 12 mpg was unacceptable to me, my thought was this:
Fuel prices are forecasted to rise due to the unrest in middle east. Big oil will use this as an excuse to take fuel prices to the next ceiling. I am going to do everything in my power to continue making month long road trips of destinations on our bucket list. Further more I am not going to go any bigger, faster, or heavier to effect my 21 mpg towing average. As I look around this campground tonight, other than a few tents, everyone is camping in giant rv's with slide outs I could park in. My thinking is not the norm. I read something this week that many campgrounds are being remodeled for larger pull thru's, E/W/S, and wifi to accommodate the ever growing average size of todays RV and the extra toys or vehicles they drag behind.