Increasing MPG with 31" All-Terrians
 

Here is my idea from my intro page, I moved it here to get more specific..
I would like to know where I can obtain the plastic sheets needed, about what thickness I would need for my application, and if it would have any noticeable affect. The bed needs to retain usage so a cap or full cover is not ideal.

Thanks you,
-James

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Specs on the truck;
2002 Ford Ranger XL, 2.3L, Automatic, 2wd, 4.10 Open Diff, 3" Front Spindle Lift, 2" Rear Blocks, 31x10.5r15 BFG All-Terrians, 15x8 American Racing Ventura Alloys, K&N 77 Series Intake System, Catback Magnaflow Dual Exhaust, SCT Tuned,,

I think that the thingie in the bed will work out if you can get the 13º angle that you're supposed to have. To measure it, take a profile shot of the truck from as far away as you can. Then measure with photoshop or a protractor.

As for underneath. More is better. The little blue triangles ain't much, as long as you're under there just cover up as much as you can. You'll have better results that way.

Also think about making some sort of wheel spoilers. I know 31" is a lot of tire to hide from the airstream, but you can at least make a dent in it.

Edit: Oh, and look up aeroheads posts, he mentions that the best bed cap is only a half cap. I don't know if he elaborated as to what half (tailgate or cab half) is best to cover, but it would still leave a lot of usable cargo space. Especially if you made it hinged somehow....

I will try to give the edges leading up to the tire a lip to deflect some of the air..

I am just afraid to mount any plastic near the engine/exhaust/transmission as the heat may distort the plastic..


A sweet goal would be 31 hwy mpg with 31's! "Green" and dirty!

Well with just better driving I went from 18.99mpg to 22.75mpg.. mixed city/hwy..

not a whole lot but a start; maybe with a few little air mods 25mpg might be possible..

might also inflate the tires from 32psi to 37..

Nice! That's nearly a 15% gain in a single tank.

Sure wish I could pull that off.

I bet when I lose the 43lbs each tires and get some 25lb ones it could be another 15% after a retune!:eek:

but first areo mods!

where do I get the plastic? hobby lobby? home depot?

Half-bedcover : General Motors holds a patent for a half-tonneau,which covers the back half of a pickup bed,and demonstrates lower drag than a full tonneau cover.If combined with a cab extender which tapers in as it projects rearward,with about a 12-degree incline at top,and 7-degree at sides,you get about 20% drag reduction and 10% fuel savings at 55-mph,12% at 70mph.Any of that exposed underbelly that can be shielded from the on-coming air will yield dividends at the pump.

as a fellow ranger owner[also on RF, same name] I can tell you that a grill block will work wonders. I have a 3in b/l 33x12.5's, and drive 3 mi's city and 75mi highway everyday. I was getting 14.5 on average, i did a grill block, and it bumped up to 15.5, and now i'm getting 18.5 by drafting whenever possible on the highway.
I'm thinking of putting my skid plate[stock steel style] one back on, and also making some side plates out of plastic. I've also been thinking of at least partial underbody panels. Like from the frame to the cab edge, it will be a sharp angle, but i'm thinking that it could help.

well your in luck, FE season is here, and I pulled 23mpg's this tank, hoping on 25 next tank and hopefully in the end 30! Good luck with the mods :thumbup:

true, i thought about that as well, but my fuel mileage has only varied 1~1.5 mpg from winter to summer. But i can tell the grill block difference, because it doesn't downshift as often or as early on my trip. Plus drafting... it won't downshift going up hill, it's great.

Ohh and FX2.3, do you have a E-fan? if not, get the one from Jusnes [?] modified. I have that and when i put it on last year it up'd me 2 mpg in town