improve gas mileage
improve gas mileage
(OP)
Hi,
I am interested in making a minor modification to my truck to help obtain better gas mileage. I can either put my tail gate down or I can buy a bed cover. Which would help me achieve more savings in gas mileage? I know the initial investment of a bed cover is going to probably overshadow any savings, but I am also wanting to get one for cosmetic reason anyway. I am concerned because for 4 months I have to commute an excessively large amount(12000 miles total over the 4 months) and want to get better mileage. Thank god this situation is only temporary.
bigTomHanks
I am interested in making a minor modification to my truck to help obtain better gas mileage. I can either put my tail gate down or I can buy a bed cover. Which would help me achieve more savings in gas mileage? I know the initial investment of a bed cover is going to probably overshadow any savings, but I am also wanting to get one for cosmetic reason anyway. I am concerned because for 4 months I have to commute an excessively large amount(12000 miles total over the 4 months) and want to get better mileage. Thank god this situation is only temporary.
bigTomHanks





RE: improve gas mileage
TTFN
RE: improve gas mileage
I'll be driving all of those miles on the interstate at 70 mph. How fast would I need to go to make a difference?
bigTomHanks
RE: improve gas mileage
My guess, for what it's worth, is that opening the drop gate might be better. Although, you might also need to put a diverter at the back end of your cab in any case.
Of course, your mileage savings probably can't compare to driving the same distance in a stock Honda
TTFN
RE: improve gas mileage
Anyway, SCCA ultimately mandated closed tailgate and no cover anyway.
The problem with testing when you already have made up your mind(right or wrong) is that you sub consiously fudge the test toward the expected results. With that in mind, you might try a few round trips on your truck.
Rod
RE: improve gas mileage
Just last month I read an article on this topic, in one of the trade mags ("Design News or???).
The conclusion was no real significant gain.
IMHO I dislike seeing the tail gate down, as it looks like the driver forgot and I'm wondering where he/she dropped the load. I'd rather see no tailgate or one of those web belting type or the screened 5th wheel type tailgates.
Ridged tonneau covers look great but if you often load your truck bed with large objects ridged tonneaus are a pain to deal with. Canvas type would simplify that problem somewhat.
Basically I'm siding with "evelrod" here, do some honest testing and see for yourself.
RE: improve gas mileage
I'm betting on the tailgate down. I drive a PU when I leave the sedan at home, and once drove it to the west coast and back from the deep south on a regular basis. My experience was that tailgate down (or left home) produced the best mileage. (I ocasionally had cargo that prevented me from using a cover although my daughters PU has one at this time).
Even with respect to the cover, it leaves a rectangular and flat rear end, and testing on the big rigs has shown that the flat back side of a trailer is a loss. One ocassionaly sees rigs with sloped rear end coulings when trailers do not require rear door access to reduce the drag off the rear end.
Not scientific fact, just my $0.02.
rmw
RE: improve gas mileage
RE: improve gas mileage
I must admit I do find Americans love of pick ups strange as they seem totally useless unless used for what they are designed to do, which judging by the paint work very few are.
I guess paying around $9 a gallon makes you think differently.
RE: improve gas mileage
My guess is there will be some huge vortices off the trailing edge of the cab roof, and the tray is basically operating in the backwash.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: improve gas mileage
That thing, with no more resistance than it has with its copious open area, billows out like a sail in a rearward direction. If you ever get a chance to look at one closely you will have no doubt on the wind forces on the (closed) tailgate.
Ajack1, $9/gal fuel prices would change Americans attitudes about lots of things.....(but let's don't take this thread in that direction-start another one.)
rmw
RE: improve gas mileage
ajack1, Why do I drive a PU? Can't say for sure. Perhaps it's my "hillbilly" ancestory. Most here know that I race British cars, mostly (a Mini Cooper and a Lotus Cortina) and have a 40+ year affair with cars British...that in itself gives me reason enough to drive a big Dodge 1T duelly diesel PU just to keep my sanity. Besides it gets 21+mpg and it's paid for!
Greg and Isaac, watching the "tow trucks" run off at the end of an SCTA event at the dry lakes gives a very good view of the airstream. Most run with tailgates up...from experience, I would guess.
Big Tom,---do the tests. Easy stuff. Just don't pre judge the results if you can. Tough to do, sometimes, but worth the effort to "know for yourself". Read my tag line.
Believe only half of what you see and none of what you hear!
Rod
RE: improve gas mileage
I interpreted the information you presented in the earlier post to be more lap time related, which to me is more ultimately power related than fuel efficiency related, hence my response.
Most of my experience of paying any attention to aerodynamic testing related to big rigs, not PU sized vehicles anyway. I was around in the days that Kenworth introduced the "ant eater" cab and was almost laughed off of the globe by a 'stuck in the mud' industry, and now look at over the road trucks/trailers with all their sloped noses, fairings, etc.
And, in the case of my 1t (ford) diesel PU, eventhough I might believe that better mileage can be obtained with the tail gate down, I rarely do it. Looks nerdy to me. Just not the way a self respecting PU ought to look.
Glad to see you posting if you get my drift!!
rmw
RE: improve gas mileage
My shop sign---"Never argue with the Engineer" ---from my kids.
Rod
RE: improve gas mileage
RE: improve gas mileage
He experimented some over a couple of years and was lead to beleive that the cap gave better economy
We did not do any accurate testing and most of the driving was short hauls here and there.
I know that a submarine and my bicycle helmet has a sort of bulbous rear for areo reasons. And not just a flat rear
RE: improve gas mileage
For the record, I filled up at the same station before and after each trip. It was right on the corner of the freeway ramp. My destination was also very close to the freeway,<1 mile.
RE: improve gas mileage
I also notice that the NASCAR truck series allows (mandates?) hard tonneau covers with VERY large spoilers to keep the back end of the PUs on the ground.
One more...In the few desert races I have seen, it would appear that the airflow pattern on the trucks (no tailgate) is reversed at the rear for fully half the bed length. Hmmmmm.
Rod
RE: improve gas mileage
RE: improve gas mileage