Any tips to improve fuel mileage?

[Doublebase]

10 hours ago, garagerog said:

I'm not getting into the cover vs. non-cover mpg argument, but Grumpy using one of the Gander Series Nascar trucks is probably not a good example. I believe if you pull that cover back, you're not going to see an actual truck bed, but chassis rails, a driveshaft, trailing roll-bar as part of the cage, a fuel cell, plus a lot of asphalt. Even if they had a truck bed in them, they would still use a cover to direct air on the rear spoiler for down-force, which is more for handling than absolute top speed at tracks other than Daytona or Dega.

Yes it is widely known that tonneau covers do not increase fuel economy.

[Grumpy Bear]

https://tundraheadquarters.com/the-tonneau-cover-fuel-economy-myth/

 

The myth is in believing they don't reduce drag. They absolutely will, a 4.2 to 7.8% drag reduction according to two SEMA studies done years apart. Fuel is about drag/resistance. GM's own wind-tunnel testing confirms and adds that soft covers are more effective than hard shells.  

 

What Tundra Head Quarters is call BS on is SEMA being unwilling to provide exact fuel economy improvement values. They NEVER say it doesn't do so, and somehow this has been interpreted to mean it doesn't. Just not true so I'm calling SKUNK on Tundra in their assumptions over what power is used where and ASSUMING, and incorrectly so, that it is the same for all trucks. SEMA chose wisely and with reasonable caution know this is not possible. 

 

You can say, "Widely known" I will provide a SEMA study. Two of them according to this post. I'll find those University Studies sooner or later. 

 

Then we can choose to disagree politely. Okay? 

Edited June 2, 2019 by Grumpy Bear

[aseibel]

On 5/31/2019 at 11:54 AM, dukedkt442 said:

The time of day you fill up can also drastically effect your mileage.  Fill up with 20 gallons at 6 am, and you might find it took much more fuel than 20 gallons than that afternoon at 2 pm.  20 gallons only equals 20 gallons if the temperature of those gallons is the same; on a recent trip in my Jetta, which usually obtains 31 mpg in summer and 29 mpg in winter over my 400 mile round-trip commute for work each weekend, I scored an unheard of 38 mpg.  After the next fill-up, I was down to 25.  Why?  I put fuel in the tank at the beginning of the first trip at 52* F, and filled up again that afternoon at 80*F.  The fuel expanded, giving the illusion of greater efficiency.  

I thought this was long proven to be an old wive's tale. It was based on the idea that you are paying the same price for less fuel when its warm and you get a better value when its cold.

 

Fuel is stored in underground tanks where the temperature fluctuation is much less than the air. Even if the temp did fluctuate, the density of a liquid doesn't change that much in normal atmospheric temperatures.

 

if you don't believe me, here's some more sources:

 

https://www.consumerreports.org/cro/news/2008/08/save-on-gas-with-morning-fill-ups-don-t-bet-on-it/index.htm

 

https://www.douglasvw.com/blog/is-it-better-to-buy-gas-in-the-morning/

 

 

[16LT4]

The fuel in your tank isn't underground and will definitely experience changes in volume with temperature, which affects fuel added and therefore calculated economy.  That's how a friend was able to ride his motorcycle for an hour and a half and still have his fuel tank be full.  The fuel in the tanks is also dependent on the time and temperature of its deliver (which really wouldn't be known).  The Consumer Reports test is of a couple data points and not sufficient enough to form an accurate trend line.  I definitely agree that the underground tank temperature is pretty constant, but that isn't the only variable.

 

Regardless, my point is that fuel economy calculations always leave room for confounding variables.  Using a single tank would make my Jetta a nearly 40 mpg car (whatever the cause, as it certainly wasn't driving habits... I'd actually flogged it harder than usual on that commute) when in reality it is a 30 mpg car.  The most accurate, but least practical, way would be to collect and assess the products out the tailpipe.

 

In the end, all I really care about is what it my operational costs are.

[Sierra Dan]

Great article on " Do Tonneau Covers improve MPG".

I remember seeing this on Mythbusters years back.

Mythbusters did prove that windows up A/C on did yield Slightly higher MPGs vs A/C off and windows down, simply due to drag differences.

 

https://autosneed.com/do-tonneau-covers-really-save-gas/

[garagerog]

9 hours ago, dukedkt442 said:

The fuel in your tank isn't underground and will definitely experience changes in volume with temperature, which affects fuel added and therefore calculated economy.  That's how a friend was able to ride his motorcycle for an hour and a half and still have his fuel tank be full.  The fuel in the tanks is also dependent on the time and temperature of its deliver (which really wouldn't be known).  The Consumer Reports test is of a couple data points and not sufficient enough to form an accurate trend line.  I definitely agree that the underground tank temperature is pretty constant, but that isn't the only variable.

 

Regardless, my point is that fuel economy calculations always leave room for confounding variables.  Using a single tank would make my Jetta a nearly 40 mpg car (whatever the cause, as it certainly wasn't driving habits... I'd actually flogged it harder than usual on that commute) when in reality it is a 30 mpg car.  The most accurate, but least practical, way would be to collect and assess the products out the tailpipe.

 

In the end, all I really care about is what it my operational costs are.

Had the same experience as your friend with a cycle, many moons ago I gassed up a 79 KZ1000 on the Oregon coast in 50's foggy weather, some 80 miles or so later in Portland after lunch where it was sunny and in the 80's, the tank was still full. But let's get real here, a motorcycle tank sits in the sun, whereas a p/u or car gas tank is more shielded from the elements, a motorcycle gas tank is at the very extreme of those confounding variables.

[KARNUT]

It gets really hot in the Houston area. It can get pretty cold too. The only thing I found that gets me more miles per tank is slowing down. My latest vehicle shows me my mileage per trip. It has actually caused me to accelerate slower and slow down a little. Can be frustrating too.


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[Yondu]

On 5/29/2019 at 9:22 AM, xSHIFTxNASTYx said:

Yeah, I figured that these Duratrac’s aren’t helping me at all!  I know I will pay for playing by adding stuff like I mentioned and that’s ok. 

 

I have been doing that but I am also slowly trying to retrain myself to drive a little bit slower just to let it run more efficiently. 

I lost about 3mpg with duratracs.  I got ride of them due to issues I had with them and went with a slightly less aggressive Cooper AT3 4S and reclaimed 1mpg. The truck got noticeably better mileage on the stick Fortitude HT tires. 

[Yondu]

On 6/1/2019 at 8:07 PM, Doublebase said:

Yes it is widely known that tonneau covers do not increase fuel economy.

I noticed absolutely no difference in economy when I installed one.  It would have been a nice side benefit but I got the cover to keep my stuff mostly dry. 

 

I assume a 8' box would see better aero gains than my 5'8. 

[Yondu]

On 5/31/2019 at 10:48 PM, Grumpy Bear said:

Anyone ever see a cup truck running with an open bed? Drag reduction is kind of a big dill. If they ran faster with more drag they would run open and 90 degree Gurney wings. 

 

https://www.google.com/search?q=NASCAR+Trucks&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjW66fhrsfiAhVGRK0KHSDFCmoQ_AUIESgC&biw=1344&bih=721

 

Somewhere I ran across a major university study on this topic with tunnel test. Soft bed cover works. I hit 30 mpg at 60 mph with the cover. If I thought for a second that taking it off would improve mileage it would be gone on a New York second. 

 

 

Those trucks all have spoilers.  The whole aero package is completely irrelevant to this discussion as according to your theory they should have a flat bed cover with no spoiler.

 

Additionally those trucks sit very low and I'd be willing to bet under that "bed cover" is a spider web of tubular bars making up the frame with big old wheel wells that take up most of the space. Not to mention a "bed" on one of those would only add weight and expense and since it's all fiberglass it wouldn't be able to hold any weight anyways.  

[flyingfool]

3.70 gears or 4.11 gears will increase the ability for V4 mode to stay on 4 cylinders at highway speeds and durring slight upward grades.  

 

cut out the flapper valve in the exhaust,

 

then you want the 17" steel wheels from the work truck or the police tahoe with the eco tires that run at higher psi. this has a smaller footprint on the road and less mass than the 20-22" wagon wheels.

 

Definatly want to run 91 octane that will yield 2 mpg over low grade 87 octane! 

 

next you should lower the truck to reduce turbulance and drag under the body, after that , drop your tailgate so it's not a drag bucket!!

 

 

Edited June 4, 2019 by flyingfool

[Doublebase]

On 6/3/2019 at 9:35 PM, Yondu said:

I noticed absolutely no difference in economy when I installed one.  It would have been a nice side benefit but I got the cover to keep my stuff mostly dry. 

 

I assume a 8' box would see better aero gains than my 5'8. 

Yeah I haven't either, in fact I bought mine with the assumption (because of what I've read, that covers don't help fuel economy). I just didn't really buy it for that, I bought it so I could leave some things in the bed without them getti rained on, which it works great for.

 

However if it does improve fuel economy, like some are claiming, well that's great.

[diyer2]

Wow

You guys can sure carry on about some things.

To me it's put in gas at half a tank.

MPG-It is what it is.

 

[Denali34]

Definitely DO NOT  add a supercharger, lift, bigger tires, headers or a tune to your vehicle. That will cause a loss in a couple MPG's.

[Cpl_Punishment]

On 03/06/2019 at 11:34 AM, Sierra Dan said:

Mythbusters did prove that windows up A/C on did yield Slightly higher MPGs vs A/C off and windows down, simply due to drag differences. 

If I remember correctly, windows down is more efficient below 55 mph and A/C is more efficient above 55 mph. Thinking back now, I can't decide if their test method was flawed or not, as they ran the A/C full blast, requiring the driver to wear a parka.