Testing if having the tailgate down has a difference in milage.

8) Could not swear to it but in 1973 gas shortage my uncle claimed he averaged 2.6 miles per gallon more with the tailgate down on his 72 Chevy full size with a 350.

PaPa John

I've seen it before

***spoilers***





Tailgate up wins.

Just like the last gas mileage test, they use 2 different trucks, although they are the same make model and options, they are still different. There can be a big difference from one to the other, break in period, friction, tires. Second they are using 2 different drivers. I don't think its an acurate test. Should be the same driver, in the same truck making and equal number of laps or something.

Rob

I think definate improvement with tailgate down. My 77 GMC Sprint would use approx 1/4 tank less gas on a 320 mile hiway trip with the tailgate down @ 70mph. I never checked the numbers but I use to do the trip every 2 weeks for about a year and it was pretty consistant car
was a stock 305-2bbl auto, stock rear end

Pretty good visual with the fluid flowing in the tank they did. I'd say they're right on.

I'd never ride around with the tailgate of my elky down anyway, I prefer a tonneau cover, that's the way to get the best milage.

about the only way to improve mileage is a tonneu cover. I had a aeronautical engineer explain that the further the air has to "fall" from the top of the cab the worse the gas mileage will be(increased friction). When the tailgate is up a pillow of air creates a raised false bed and the air falls about half way down. The air falls all the way down with no tailgate and the air falls the least when you have a cover on.

When I used to run my gold elky I would get consistantly faster 1/4 mile times with the gate up at the absolute astonishment of the "know it all's" - if you don't know one, you are one :)

Just a side note, with the tailgate down you run a risk of flexing your bed and distorting it to the point you can't close your tail gate.

I'm confused...if your that concerned with gas mileage you need to sell your Elky and buy a car with a 4 banger or a hybrid. The tailgate should be up if nothing else to protect it from some lil ole lady from Pasadena crushing it when she tries to double park her car behind your Elky. It wasn't made to act as a bumper. Put the gate up and a tonneau cover on.

there is plenty of evidence that a tailgate up or down makes no measurable difference in mileage. main point is your bed is stronger with the gate up.

Tailgate down, tailgate up---take the damn thing off and install a net.

Tailgate down, tailgate up---take the damn thing off and install a net.

Now what does that gain?

Less weight?

There was an extensive discussion about tailgate vs. mileage at this thread...

http://elcaminocentral.com/ftopic-4138-0-days0-orderasc-tailgate.html

I also seem to remember reading that the difference is soooo small, that it only helps if you are driving long, expressway trips, not city driving.

I seem to remember a post with a pic of a 5th gen with one of those BIG spoilers mounted on the roof...if driving with the tailgate down increases gas mileage because of aerodynamics , then technically wouldn't one of those BIG spoilers increase gas mileage also. The aerodynamics created by one of those BIG spoilers would create so much lift at high speed that your wheels would only be on the ground approx 50% of the time thus cutting fuel consumption equally by 50%. "For every action, there's an equal and opposite reaction" or is it E=MC 2 Man I love physics...it's cool! 8)

If you replace the tailgate with a net where do you put the license plate? Do you just duct tape to the rear window? How do you provide a tag light if the tag is in the window?

8) Thus when the wheels lose contact the vehicle loses speed thus losing lift causing the vehicle to have to again gain more speed to achieve lift thus expending additional fuel in a cycle of slowing and then accelerating again. :?:

PaPa John

OK professor, it' s only a theory, work with me will ya? I'm trying to solve our dependancy on foreign oil here. Hmmmm...larger winged spoiler = greater lift?

8) Sorry! :oops: My mind accidently went into overdrive! :lol: :lol:

PaPa John

Wait...I'm on to something...now I know why the ricers get better gas mileage...it's those big winged spoilers on them. Darn they beat me to it! :mad:

If you replace the tailgate with a net where do you put the license plate? Do you just duct tape to the rear window? How do you provide a tag light if the tag is in the window?

Duct tape a flashlight to the rear window or for that custom look you can use a Maglite and "spotlight" the tag by taping it to a suitable location on the bed rim. :P

Double Take!!! :-)

Let's see... the spoiler issue! The purpose is not to provide lift but downforce to allow better cornering and stability. The spoiler effect also creates a low preasure are below itself and behind the car/truck that allows the displaced air a confortable place to rest but that force is balanced and ofter overcome by the drag produced by the spoiler itself therefore spoilers increase drag and thus lower gas mileage.

But who says you have to install it properly. :lol:

The purpose is not to provide lift but downforce to allow better cornering and stability.

Correct.

tailgate down=tailgate smashed in

The license plate problem is the easy one to fix BUY A GEN 1, 2 OR 3 with a BIG BLOCK then you do not have to worry about the plate or fuel consumption any more as you will consume all you can get!!!!

I have had 4 elky's a 67, 68, 69 and my pesent 69 SS BB. I have done that test on every Elky I have owned and it makes a every small amount on the open hwy or freeway but nothing around town stop and go stuff. If you add in the toneau cover you do improve even more on the road and only my small block 67 4 speed showed anything around town. All 4 cars did better with the cover. But I do not think the around town test was very good as it still was not the same road for the exact same miles just a typical gallons divided by miles test when it was time to fill but was mutipal tanks of gas. "There is no help for the Big Block it just uses it all quick"

Okay, so the next time someone posts the same tailgate up vs. down question, let be unanimous and say it just doesn't make enough difference to worry about it.

Leave the tailgate up, and if you are worried about gas mileage, get a cover.

Agreed?

Leave the tailgate up, and if you are worried about gas mileage, get a cover.

Agreed?

How about if you are worried about gas mileage dont get a truck/el camino?

NO JUST SWITCH TO "LP" :cool:

Or hydrogen injection will help mileage. :-P

How about if you are worried about gas mileage dont get a truck/el camino?

Agreed.

I was thinking about this since my last post on the subject, so I did a little research.

Turns out, wind tunnel tests confirm the tailgate, when left up, creates eddy currents in the air stream and makes the truck more aerodynamic. This allows the truck to get maximum fuel mileage by creating a smoother overall airflow. Design engineers have data that prove higher mileage is always obtained with tailgates up.

On to our next technical discussion...How do I set a laser printer to stun?

Setting you laser printer to stun should only be done by a professional IT person. It can be VERY DANGEROUS (http://www.cartoonstock.com/directory/l/laser_printer.asp) 8O

Please leave this to fully qualified persons!!!

Can't help with this problem --tailgate welded shut/filled-- :P I'am kinda stuck in the tailgate UP group,but if you want good mileage take out the V8 and put in a 6---NOT-- :lol: