Better MPGs with Tow/Haul engaged

I thought I would experiment with tow/haul on return trip from hunting lease. It definitely wakes up the throttle response and my exhaust is louder especially when accelerating. MPGs surprised me. Running 70-80 on 2 lane hwy with one high speed pass I got 18 on meter. Now I know the meter is not correct but I use it for comparison. On same trip a month ago it was at 17 or little less without tow/haul on. Every time I have checked meter it was about .3 favorable. Most of drive is hilly but I did have a little bit of a tailwind.

 

I'll have to try this. Mine stays at 15.2, will not get any higher, it'll go lower lol.

 

Wow that is really hard to believe. It seems it should be the other way around.

 

I figure a little bit might be due to break in but not that much.

 

Considering all the other factors that influence fuel economy including wind (as you said), temperature, fuel, time of year, weather in general, other traffic, tire pressure, tire condition, speed etc etc etc... I don't think you can claim the 5% difference was due to the tow button. JMO

 

Almost everything was identical. Same weather, same gas, same psi in tires, same roads, same traffic, same wind direction, one month apart.

 

When I had my tow haul on.. i got WAY WORSE MPG . Huge difference when using it

 

I use my tow haul button every time I️ drive my truck. Makes for not having to mash the pedal so hard when driving regularly.

 

All those factors could be close to the same but they are still not exactly the same. All I meant was when all the small differences add up for only a 5% difference, I don't think that's enough to claim the tow button gives better fuel economy. It's pretty easy to lower your gas mileage on the highway by just going a few mph higher for a bit.

 

I'll have to try that as well! I was getting 15.2 ~ 15.5 until I purchased a tonneau cover (ARE Fiberglass). After installation I have been consistently at 18.2. I'm older, so I don't have a heavy foot anymore.......

 

My MPG gets worse with tow/haul in use. Generally, the logic is that higher RPM's means more torque at the expense of efficiency. I've actually experimented with the tow/haul mode while towing my trailer. I get better mpg's when not using it while towing my trailer.

 

I experimented with it while unloaded on highway trips in the past as well, I saw basically identical MPGs but much better driving feel(better throttle response, easier acceleration). What I did notice with tow/haul engaged is that I would get better mpg on hilly areas where it would seemingly downshift sooner, upshift later, and kept the torque converter locked up. And as mentioned, my exhaust definitely sounded a little louder/more aggressive with it on.

 

I am thinking hills are the reason I got better MPGs on route I tested it on. I was also thinking speed as I was consistently driving 75 - 80. Actually when drove same route the first time I was driving slower. I know it was not a scientific test under controlled conditions but was curious if anyone else had noticed the same thing. I did have 1000 more miles on truck when I drove the route with tow haul on. I will drive the same route 4-5 times before hunting season is over so will do some more testing.

 

Doubtful that a tonneau cover adds 3 MPG

 

big question is how many miles did u drive?

display mpg is not accurate or instantaneous ...
also in hilly area if the car is in D, it will keep and/or shift to lower gears (due to the hills) much more than flat road so it may not be that much different than being in the "Tow" mode which has a different shift schedule! it depends on hills obviously but I have found that the car is pretty smart when in D and going up hill at certain/lower speeds. so many factors ... I haven't towed much yet so not sure how D handles towing. maybe not that good since there is a Tow button to help out!

also jet streams affect the fuel economy big time when flying. at 70-80 mph u were almost ready for take off ... lol

 

All of the tests I have seen stated no improvement in MPGs and some showed decrease. To other poster drive was 200 miles and I reset the MPG meter at the beginning each time.

 

This has already been debunked elsewhere, same with driving with the nannies off. Dig around.

 

I hadn't turned my tow haul on since I got my truck until reading this. Much more fun to drive. It's like sport mode on my wife's Tuscon...

 

Tow/haul is the poor mans supercharger, which is mine till I get enough money for a full race exhaust system by Keith Carty, supercharger is too expensive and especially in CA with premium fuel prices going stupid it’s a robbery

 

I would think that T/H decreases MPGs.

Since we talk MPGs, I picked up my new 18 Limited CM yesterday and drove about 180 miles (30 city, 150 interstate with cruise set at 70) and the gauge showed 18.1 mpg. That is about 3 mpg less then I got with my 16 F150 EB under similar conditions. I don't consider that pretty good and it was better then expected, especially for a brand new engine.

Tonneau cover: I had one on every truck I ever owned and it didn't make a damn bit of difference as far as fuel consumption. I did order another MX4 for the Tundra yesterday.

 

I don't wish to get into a debate. I can only speak from my experience. I ran my truck for one year without a tonneau cover. I consistently resist the MPG calculator and maintained around 15 ~ 15.2. Then I started researching about tonneau covers. Yes, they do add weight. Especially, the fiberglass one like I have. The one I have is around 130 lbs. My understanding is the tailgate with an open bed arocts as a wind trap. This slows down the trucks speed. When I looked at the literature and research on-line I found varying studies. Most state that is dependent on driving habits. If I recall correctly on ARE website or maybe a brochure. They stated that you results would vary. I have been consistently at 18.1 ~ 18.2 since adding the tonneau cover. My driving habits haven't changed that I am aware of. How would you explain the increase? I am very happy with my choice of adding the cover by the way.

 

I found this on the website for ARE. I am not sure why they would post this research if it didn't have some validity!


Does a Tonneau Cover Affect Fuel Economy?
Click Here For Kilometers Per Liter Savings Calculations


Do the Math!

According to these studies, it does...



From the SEMA Research and Information Center -
According a study conducted by Western New England College's Department of Mechanical Engineers, "The best way to reduce drag, and improve gas mileage for pickup trucks, is to add a tonneau cover." Their study yielded gas mileage savings of 8% by adding a tonneau cover to a Dodge Ram.

From Auto Trim & Restyling News - August 2001
From "Tailgate Talk - Does Removing A Tailgate Affect Fuel Economy?"
By Bruce W. Smith

According to many experts, the best way to improve a pickup's fuel economy is to leave the tailgate up and cover the bed with a quality aftermarket Tonneau cover. "Tonneau covers on pickup boxes reduce aerodynamic drag," said Ford's Jack Williams. "We've seen reductions of about 8 to 10 percent on the F150. The average steady-state [cruise control] fuel economy improvement at highway speeds is closer to 5 percent."

Gas Savings Calculator
Cost of Gas Per Gallon
Current Miles Per Gallon Your Truck Averages
Miles You Drive Monthly
Gas Mileage Saving Estimate

 

I'm happy that you are getting better mpg's with a tonneau cover. I have not noticed any difference in any of the 3 trucks that I have owned with or without the tonneau cover when it came to fuel efficiency. I put them on to protect the stuff in the bed of the truck and to keep the snow out.

ARE is somewhat biased aren't they? They want to sell more tonneau covers. The other two sources claim a fuel economy savings of 8% on a Dodge Ram and 5% on an F150.

If you went from 15.1 to 18.1, then you are showing a 20% improvement. That is quite a lot, and well above the claims of the 2 sources you cited.

My point is that your fuel economy must also be influenced by other reasons such as: engine break-in, you're not as lead footed as when you first got the truck, you are driving in more highway than stop & go, etc.

Again, I am happy you are getting 18.1. I am not experiencing anywhere near that. I'm only getting about 15 and I did not lift the truck or put big tires or anything. I wish I were getting what you are getting.

 

gdiep,

Thanks for the response. I am not sure how much of an influence the break-in has on MPG. I do know that I have talked to several Tundra owners at gas stations. Most are getting even less than 15 mpg. I typically drive the speed limit and do not make any sudden acceleration changes. So all of these may be contributing in a positive way to my current mpg. I am happy with it in any case!

Everyone wants a piece of the market share. I just wanted to build a foundation for my findings based on what I had read previously. I had never owned a tonneau cover of any kind previously. So, I wasn't sure what kind of results I would achieve.

I plan on doing a check with the tow/haul the next time I pull my boat. I'll reset the mpg calculator and see what results I get. Then I will post to this thread.

Thanks and have a great day.

 

Interested in what you find out about towing your boat. I tow a 4500 lb travel trailer and have noticed that using the tow/haul button uses more gas than normal. When I tow on the interstate, I just run in normal. If there's a lot of stop & go like in city streets or if the area is really hilly, I use tow/haul to take advantage of the engine braking at the expense of gas mileage.

 

Ksatter,

I hope you right. I get my MX4 tomorrow and it will go on the truck the next day and I will take any MPG improvement I can get. I drive the same way you do; conservatively, gradual acceleration and I usually don't exceed the posted speed limit. Like I said in post #21, I got pretty good MPGs on my first drive. I am sure it will get a little better once the engine is broken in and maybe the MX4 will help a bit. I consistently exceeded the MPG ratings with all my previous trucks do to my driving style and I am sure the Tundra will not be any different.

The exception is when I drive my Chevelle. I consistently get about 9 MPG but I do have a lot of fun, the Tundra is an economy cruiser in comparison.

 

Took the boat out today. Reset MPG calculator and placed in Tow/Haul mode. Went from my normal 18.1 mpg down to 10.6 mpg. Wow! I need to do a longer test on pulling the boat. After returning home and unhooking the boat. I went and filled up and reset MPG calculator. I returned to the previous norm of 18.1 mpg.

Hope this information helps.

 

Myth Busters did something about this a couple years ago. Turns out, at one time this would've made a big difference. But with newer trucks, they take aerodynamics into account, and have made changes to the front ends and cab design to eliminate tailgate drag.

 

I just got done putting on my Mx4 cover. My wife wants to go shopping tomorrow so there will be 160 miles round trip on the interstate plus about 30 miles of city traffic.........we'll see what happens.

By the way I can get better then 19 mpg driving around here (two small towns and Ft. Leonard Wood) where the highest speed limit is 45 MPH, its like city driving without a lot of stop & go. Obviously you have to make an effort to get those results; I am not holding up traffic, just driving smart.