Looking for better mileage?

I think people who say that the tailgate down is worse for fuel mileage got that information from Mythbusters. No offense TuRDTACO or docc30.

However what everyone who heard that needs to remember is that they only tested one make, one model, and one cab configuration, so while that may in-fact be a true statement on the (I think it was a) dakota they tested. It may not be the same on the Tacoma, or it even may not be the same from TSUNAMI*22's 5 lug Taco, to my access cab 4x4.

However, (and this is old information ie: it was a problem years ago, and may not still be the case) I would caution against driving with the gate down or off on a regular basis as it is a structural part of the truck, and does provide some support to the bed sides, so your best bet is still probably a tonneau cover.

Just my $0.02

 

Driving with a meshed tailgate lets the air pass through it - which creates a decent amount of turbulence on the rear of the mesh - which causes drag directed aft of the truck which means - more power needed to overcome the drag.

The more power required to overcome drag = more fuel consumption.

Drag Formula = AoA x 1/2p x V(squared) x S Where:

AoA= Angle of Attack
1/2P= Air density
V= Velocity (squared)
S= Surface area

Drag goes up 4 times to the square of the airspeed.

(3) basic types of drag:

Parasite: Created on non-lifting protrusion in the airstream.
Profile: Created by the shape and thickness passing through the air.
Induced: Created as a by-product of generated lift. Decreases with airspeed.

Parasite and profile are present in our situation for the most part.

We now return you to your regularly scheduled program.

 

Another BS mythbuster event was where they say that you can't make a Fastball (pitch) actually climb.

In truth, if the pitcher can get a fast enough back-spin on the ball, the Magnus (aerodynamc) effect on the ball may overcome it's weight and actually climb slightly.

It all depends if the pitcher can spin it fast enough. and the density of the air.

Unlikely, maybe. Impossible? No.

No offense to anyone out there, but the MythBusers are for interesting entertainment purposes for the most part.

Don't rely on their statements as gospel.

 

buy a tonneau lol... trust me tailgate up or down doesnt make a difference in MOST cases but I have seen reduced mpg from a tailgate down...never seen anything but gains from a tonneau or a cap as it make the truck more streamlined for the air..passes over cab lands on cover and rolls off back...not hitting the tailgate

 

There's actually an SAE paper out there where a study was done between a few full size pickups and their drag with tailgate up/down, tonneau, net, etc.

Here's a link:

http://ecow.engr.wisc.edu/cgi-bin/get/me/363/ghandhi1/pickup.pdf

The best way to tell the difference is experimentally, those equations for drag are pretty general and won't apply very well at all to the back of a pick-up.

 

just what i heard, i'll take the tailgate off of my jeep tomorrow and try getting to 40mpg

 

stop looking smart, it's irritating

 

That was an awesome explanation. I agree with the earlier posts about how your driving effects the MPG's the most. Ever since I installed my SGII, I find myself trying to keep the MPG up and the CPM down. This tank, I am around 22 MPG, but I am 23 miles of hwy from work. City driving kills my MPG's.

 

Why? I earned every bit of them.

 

i know but when i was trying to read it last night i didn't bother trying to understand it so i got mad

 

Don't be mad. I'm only trying to help people understand what's really happening. You included.

Some of what I say can go over people's heads. That's nothing to be ashamed of. If you have a question, just ask. I'm happy to explain.

We all continue to learn until the day we pass on. Something new everyday.

Embrace it.

 

problem is i'm always on here so late, hours and hours after my brain has shut down for the day...thus very little comprehension

 

i actually speak arabic late at night

 

Haha.

Yeah? I have reason to be up this late. I just had some crappy news come my way and I'm trying to deal with it.

In short, the company I trained to fly with just went bankrupt due to the lending crisis. 700+ flight instructors, many of them my friends that I care about, just lost their jobs. They also have to still pay their loans off that enabled them to become flight instructors.

Crappy all the way around. I'm lucky I finished my training in time. At least I have something to show for it.

Where I was just about to get hired by this company, now is gone like a fart in the wind. I'm 44 and no job. My worst fear is flipping burgers at McDonalds along with 3 other ex-CFI's.

Can't seem to sleep.

 

damn...you have me beat, i don't have any sort of a good reason like that, i'm just young i guess

 

Go back to stock tires and lift.
Keep your motor and intake in tune.
Find a set of "underdrive" pulleys to get rid of parastic drag on your motor.
or your best bet, buy a more economic vechicle to drive.

 

Hello,
Thought I would add onto this thread since I am having the same type of issues. I have a 98 ext. cab 4wd SR5 with the v6 and a 5 speed with only 67000 miles on it. It had the 15x7 wheels on it when I bought it with slightly larger than stock tires. When I replaced the tires I went with 31 x 10.5 tires.
I went from high 18's - low 19's to mid to high 17's for mileage. I took it to the dealer, as I had an o2 sensor die and they said tune up, and fuel injection cleaning should help but the tires were hurting me. Since then I did the fuel injection cleaning and the tune up and my mileage is steadily getting worse. It had dropped to 16's then 15's and now for the last 3 tank fulls I have been lucky to hit 14.
I don't let it sit and idle longer than it takes me to scrape the windows. I am noticing that i does not start as easy as it used to. Also a few times I have noticed a raw fuel smell as I am scraping windows. A couple times it was bad enough that I smelled like it when I got back in the truck. I don't notice it leaking anywhere. I am getting ready to take it in to get it looked at and was looking for ideas to have them look at. Thanks.

 

Ok guys, use some common sense and save your money thinking something went wrong with your mileage. Here's whats going on.

Changing to bigger diameter tires in effect allows the tires to roll less rpms for a given distance.

1 mile distance with regular tires "factory size" should equal 1.0 on the odometer.

Increase the tire size and 1 mile actual will read 1/2 miles (0.5) on the odometer. I'm exaggerating this to make the point.

bigger diameter = less cumulative tire revolutions for a given distance = lower odometer reading for actual miles driven = lower mpg if measured by dividing gas used x odometer reading.

Make sense?

Also, taller diameter tires will "lug" the motor a tad. This might effect the mileage as well. It would have the same effect as running a rear-end diff that was wayyy too tall. Like triple overdrive.

I think your answer would be to recalibrate the odometer and you'll probably see the original mileage return.

Don't let the dealers bilk you because you don't know any better.

 

In your case it sounds like its an engine problem...or bad fuel. Even with an uncalibrated odometer your mileage, although indicating worse than before, - should remain consistent.

Also make sure that you are filling it up to the same level everytime. Pumps all shut off at different levels.

I have personally found that after the pump stops I can still trickle pump the gas visually and insert an additional 2 gallons! The Toyota Tacoma filler neck SUCKS! You have to let the bubbles flatten out and then fill...and so on, and so forth - until it's topped off. Even then there still might be a bubble trapped in mid-tank unable to reach the filler neck.

 

is winter gas used in eastern nc?