Surprisingly Bad Fuel Economy

[Theberrys]

Originally Posted by raven7usa

Here's something that's not on paper that may answer some of your questions about the Eco-boost 3.5

Wow that's impressive

Makes me think the little 1.6 in my Escape will outlast me in normal use.

Dick

[LTZ470]

Originally Posted by okdrew

Thanks LTZ470 - I am not sure how/if I can change my gearing. I will do some research (always fun). That said, I am reluctant to change much whiled the warranty is in place.

Drew.

I added one of these for a little more go juice as well...

[davendeb]

Still, if gas will do the job safely, efficiently and without maxing out the TV tow limits, its hard to justify the extra costs of a diesel engine, diesel fuel per gal, maintenance, etc. I could not tow enough for the rest of my life to make back the added exp of a diesel. But,,,, if I moved up to a bigger rig, diesel, without a question, would be the choice.

[fvstringpicker]

Originally Posted by davidjc

Still, if gas will do the job safely, efficiently and without maxing out the TV tow limits, its hard to justify the extra costs of a diesel engine, diesel fuel per gal, maintenance, etc.

I have to agree. If you're under 7-8k pounds, the extra $10k for a diesel is not likely worth it. (but like my bumper sticker sez, "real trucks don't have spark plugs" just kidding)

[KSCRUDE]

Originally Posted by LTZ470

I added one of these for a little more go juice as well...

We've got a 14 Shelby Ford Raptor on order with a Whipple suppercharger, 575 HP and other upgrades. First time Shelby has ever made a pickup. Should be done by January. Just in time for my January 20 birthday. I'm not getting any younger and you can't take it with you. The kids will have to do for themselves. I don't care if we spend it all.

[davendeb]

Originally Posted by fvstringpicker

I have to agree. If you're under 7-8k pounds, the extra $10k for a diesel is not likely worth it. (but like my bumper sticker sez, "real trucks don't have spark plugs" just kidding)

Haha. Plus the 50 cents per gal fuel increase.

[LTZ470]

Originally Posted by KSCRUDE

We've got a 14 Shelby Ford Raptor on order with a Whipple suppercharger, 575 HP and other upgrades. First time Shelby has ever made a pickup. Should be done by January. Just in time for my January 20 birthday. I'm not getting any younger and you can't take it with you. The kids will have to do for themselves. I don't care if we spend it all.

The "main" factor for a Supercharger for smaller engines is torque...the Screw Type superchargers produce much more down low torque than the Turbine type chargers, but may not produce as much horsepower at the upper end rpm's, but for towing or pulling who cares? Down low is where they require help to get all the weight moving. Jeeps are heavy due to being extended for 4 doors and then 4X4, the screw type superchargers give them a nice boost of torque down low to get them going, add 4:56 or 4:88 gears and they really pull nicely...should have came from the factory that way!

That Raptor is going to have 500+ Hp and almost 500 ft/lbs torque! at rear wheels...if you let the kids drive it, better invest in another set of rear tires for spares...lol...she should "haul the mail" for sure!

[caissiel]

Originally Posted by Piker

Many have made the point that wind resistance is a huge factor in fuel economy... I believe this to be a valid statement.

But to say that weight is not as big a factor is probably not accurate... at best it could be said that "it depends." In stop and go traffic, or in hilly or mountainous terrain where speeds may never go above 30 or 40 mph, weight will play a much larger role in fuel economy than wind resistance.

Weight will also play a larger role in the reliability of the drivetrain. If you're driving around in your V-6 tow vehicle pulling 5,000 lbs with your foot mashed to the floor all the time to get you moving and to keep you moving, you can bet you're putting extra strain on things. Especially engine head gaskets and transmission clutches. When an automatic transmission upshifts at 5000rpm pulling that kind of load, there will be a certain amount of slippage of the clutches, and tons of heat produced.

Add to that the fact that many vehicles have a "tow rating" but aren't really built for towing. Most will cycle the torque converter in and out of lock-up way too much... also generating heat... Towing in overdrive also generates more heat.

Stopping to cool the engine and tranny down every tank of fuel will not prevent damage if your driving around overheated between fuel stops. Vehicles aren't like people in the sense that they need to rest... they should be able to keep running until they're worn out. Your engine and transmission's cooling systems must be adequate for pulling that kind of load, and capable of carrying away the heat under the conditions that you drive in or you're just asking for problems. Period

I'd wager a guess that most vehicles with a V-6 power plant really aren't outfitted properly for towing. Most of them don't have transmission temperature gauges for sure. Heck, even on your half ton pickup trucks with V-8's, they recommend a "tow package" which includes extra cooling capacity for the engine and tranny.

I'm not saying you can't tow 2.5 tons with a V-6... people do it all the time... I am saying that if you do there is good reason to be a little more cautious about how much weight you pull, how often you pull it, and the way you drive if you want your vehicle to last.

Just my $0.02. Take it or leave it.

-cheers

You are right on. A driver needs to understand the limits. No gas engine is equipped to exhaust the heat off the engine properly while towing and trying to keep rpm down while towing to save fuel only aids to the wear of the powertrain. RPM kept high with improved exhaust will go a long way while getting rid of the heat and decreasing torque and wear. Stopping surely is not the answer, it needs to happen while driving.

[Dan berkey]

I have a 2008 F250 pulling a 11000 lb tt.....I get 8mph with a gasser

[Rednax]

Originally Posted by okdrew

Hi Folks,

I have a 2103 Toyota Tacoma V6 4WD (GCWR = 11,100, GVWR = 5450), and I am pulling a Kodiak 221RBSL (Dry 4616, normal kind of load for two people camping, so I am guessing up around 5600lbs - I try not to travel with anything in the tanks). Truck has a rated tow capacity of 6400lbs. I included the GCWR and GVWR as I know that calculating tow capacities is a complex thing .

The truck pulls OK all the way to 70mph, but seems happier around 60. I have a WDH and sway bar so handling is good. What has surprised me is that I am getting slightly less than 10mpg on a run, even less with a strong headwind (not surprising) where it drops to about 8.5mpg.

This seems low to me - I am not sure what I was expecting, but not this.

Any thoughts or comments? Anyone have a comparison of a similar set up?

I am getting the fuel stats from an OBD Reader as well as good old fashioned math. All numbers are US gallons.

Thanks,

Drew.

Helps to make a comparative test. With the TV loaded as if for a trailer camping trip, make a 100-mile drive at the same speed as if you were towing. I recommend 60-mph as that is the point where air resistance skyrockets and it is a decent speed given the real limitations of ST trailer tires.

Take the trailer along for the second round trip otherwise the same (same fuel station, same pump, etc). Likely, you'll see a 30-40% decline from the solo mpg. The trick is in reducing that percentage to the lower of the two.

Keep records of all gallons and all miles. One wants to see a percentage improvement to the baseline. The average mpg is all that counts, not highs or lows. For example, were you to increase the average from 7.5-mpg to 9-mpg it would be a 20% improvement!

From here make the calculations that arrive at a fuel cents-per-mile number. Life is easier in trip planning thereby. If I know (I do) that my towing fuel cost is 25-cpm then figuring a major expense of a trip is well covered.

Next, do not assume that the TT has adequate bearing grease or adjustment, or that the axle alignment is correct. Same for brake adjustment. Tires should be at maximum sidewall pressure. Be meticulous. Details matter in optimizing the rig. The RV factories and dealers can be sloppy.

On the truck one wants the tire pressure to reflect the actual load when the trailer is hooked up and WD applied. And, as with the TT, that the tire loads reflect -- FF/RR and side/side -- a decent load balancing. And a tonneau cover will add some streamlining (a topper shell not so much, but durned handy for what you cary along).

As to setting up the WDH one is best off in using actual weight values, not guesstimates. Take a look at threads on using a weight scale to set your WD hitch properly. Do not leave performance on the table by a "good enough" approach. Again, be meticulous. Reducing steering inputs per 100-miles is a measurable benefit, not to mention better handling and braking.

And, just as you may have figured in the cost of a TT/TV combination to your annual budget, do the same with fuel. It is possible to do quite a lot with a fixed annual fuel budget to help underwrite vacation travel:

http://www.irv2.com/forums/f59/high-...ml#post1103397

.

[okdrew]

Originally Posted by Rednax

Helps to make a comparative test. With the TV loaded as if for a trailer camping trip, make a 100-mile drive at the same speed as if you were towing. I recommend 60-mph as that is the point where air resistance skyrockets and it is a decent speed given the real limitations of ST trailer tires.

Take the trailer along for the second round trip otherwise the same (same fuel station, same pump, etc). Likely, you'll see a 30-40% decline from the solo mpg. The trick is in reducing that percentage to the lower of the two.

Keep records of all gallons and all miles. One wants to see a percentage improvement to the baseline. The average mpg is all that counts, not highs or lows. For example, were you to increase the average from 7.5-mpg to 9-mpg it would be a 20% improvement!

From here make the calculations that arrive at a fuel cents-per-mile number. Life is easier in trip planning thereby. If I know (I do) that my towing fuel cost is 25-cpm then figuring a major expense of a trip is well covered.

Next, do not assume that the TT has adequate bearing grease or adjustment, or that the axle alignment is correct. Same for brake adjustment. Tires should be at maximum sidewall pressure. Be meticulous. Details matter in optimizing the rig. The RV factories and dealers can be sloppy.

On the truck one wants the tire pressure to reflect the actual load when the trailer is hooked up and WD applied. And, as with the TT, that the tire loads reflect -- FF/RR and side/side -- a decent load balancing. And a tonneau cover will add some streamlining (a topper shell not so much, but durned handy for what you cary along).

As to setting up the WDH one is best off in using actual weight values, not guesstimates. Take a look at threads on using a weight scale to set your WD hitch properly. Do not leave performance on the table by a "good enough" approach. Again, be meticulous. Reducing steering inputs per 100-miles is a measurable benefit, not to mention better handling and braking.

And, just as you may have figured in the cost of a TT/TV combination to your annual budget, do the same with fuel. It is possible to do quite a lot with a fixed annual fuel budget to help underwrite vacation travel:

http://www.irv2.com/forums/f59/high-...ml#post1103397

.

Hi Rednax,

Thanks for such an informative post with so many good suggestions. I appreciate it. I have not done Any of these things other than the tire pressures. I do believe the twin axles on the trailer to be slightly out of adjustment - I am having these looked at Under warranty in a few weeks. The WDH was set up by the dealer - I have no experience with WH so accepted their settings without question.

Lots for me to check. Thanks again.

Drew.

[Superslif]

Thanx DavidJC

I tow with 2008 tundra, 5.7 limited double cab. First towed a 2006 26' Jayco @4500 lbs and got 12-13mpg up the blue ridge parkway. Then towed 8700lb, 2010 wildcat 5th wheel and got @7-9 mpg. Just traded in for 2013 rockwood ultra lite 5th wheel @7700lbs and been getting a steady 10 mpg.

At about what speed were you towing at? and towing the 4500lb tt did the Tundra stay in over-drive?

Looked today at a 13' Tundra double cab 4x4 5.7L and it was listed at 13/17 where my 2005 4-Runner 4.7L (V-8) is rated at 14/18 and I get 16-17 city and 21 -23.5 highway...

If I knew I could get 12 mpg towing with a 5.7L Tundra I would be a happy camper.

I know the 2014 Tundra's have a new interior and exterior, but the same drive train....I'm kind of disappointed that Toyota has not upgraded the driveline for the Tundra....That same 5.7L dates back to the 2007 model year. I guess I have to wait till the 14's come out....

[davendeb]

Superslif. The trip in question was from north Louisiana to Gatlinburg Tennessee, then up the blue ridge parkway from north Carolina to Shenandoah Virginia on the skyline drive. Hilly and steep. Max speed for me is 65 but mostly stay 60-62 on highways. Most of this trip was slower as we were in the mountains in autumn and leaves were beautiful. Lots of stopping and starting. The little jayco at 4500lbs dry is less than half tundra tow capacity so mpg was better.
Tundra doesn't have over drive. It uses all 6 gears even in tow/haul mode. In t/h mode the shift points are stretched out to hold you in lower gear longer before shifting. It stays in 6th all the time on level ground and downshifts as necessary on steep inclines. Hope this helps.

[davendeb]

Oh yeah. I have 2 WD limited double cab. I get 18 mpg at 75 mph and 21 at 60 mph unloaded.