OT: would this work?

[Daddy Dee]

Here's a problem and a scenario for solution I've been imagining for some time, but don't have the technical knowlege to know if it would work or not.

I drive a '99 Ford F-150 as my main vehicle and have always liked it. Before that in our family, we also drove a Chevrolet Caprice and now a Ford Crown Victoria. Both of these cars could achieve 25 mpg or better on the highway. This is impressive, IMO, considering the size and weight of the vehicles. My F-150 gets 16-18 on the road, and this is with a five speed overdrive transmission.

In my very lay understanding, it is the rear end gear ratio which prevents the pickup from achieving similar gas mileage. Of course, it would be a matter of design that the pickup would be geared lower in order to be suitable for pulling loads. In my case, I have very seldom ever needed such a capacity.

What I've been wondering about are possibilities to improve the mileage of the F-150. So far, I'm skeptical of claims for H20 mods. Would it work to replace the drive train of the F-150 with a Crown Vic drive train?

I'd asked a question about changing out the pickup's rear end and he mentioned that the new rear end would mess up the F-150 computer and it wouldn't run.

My understanding is admittedly quite lay, but it would seem to be an asset to Ford if they would manufacture a "gentlemen's pickup" with a Crown Vic drive train. I imagine that most pickups on the road are used like mine, that is much lighter service than that for which they are designed.

I'd go out and buy another F150 in a heart beat if it got mileage similar to the Crown Vic.

Is this a faulty expectation? How doable would such a change be if it were to be executed?

Any help appreciated.

[Tom Adams]

I'd find out what the rear end gearing currently is in your truck and then ask the Ford parts guy what ring gear your rear end would accept. I'm mostly familiar with Chevy products, so I'll use that for illustration.

Let's say that your rear end is a 3.90:1. That same rear end housing can accomodate a ring gear that will give a ratio of 3.73:1. Not sure what the gas mileage savings would be, but you get the picture.

Changing out the ring gear would be less expensive than a complete rear end swap and, assuming you didn't go from like a 4.10:1 to a 3.05:1 there shouldn't be an issue with the engine management computer.

Tom

[jacksonbart]

No dice, buy a used Corolla or a Chevy Cobalt

[Jay481985]

you can probably get one of those roofs to reduce drag. my current car has air coefficent of .27 so it gets anywhere between 32-40 mpg (32 if i am speeding 40 if i keep it at 50)

also with the crown vic comment, at speed it is more about the drag then the engine. You need power to overcome inertia when you start from a standstill or want to accelerate but you need very little power to sustain the speed that you currently are at you are really only fighting air drag.

[JJkizak]

Like I said in previous threads if you can change the computer chip to get about 6 degrees more timing your milage will increase about 20%. Your nitrous oxide polution will also go out of site. The computer maintains the combustion temp at 1450 F for minimum nitrous oxides. If you have to "E" check the car then you can legally do nothing. (not even change the rear end ratio from stock) One way to accomplish this also is to junk the Ford computer and install an aftermarket Holly injection setup. But the EPA will not like you anymore and treat you lower than dog crap.

JJK

[Jay481985]

Daddy Dee,

I also forgot to mention the following:

Cold air intake? or changing your stock filter to a high volume aftermarket filter?

Tuning your exhaust

getting one of those mpg readers, I have one built into the car and I have reduced my right foot cause I can now see how bad my mpg is when i floor it (9 mpg)

properly inflated tired, or overly inflated tires (though you give up the life of the tread)

take out all the weight you don't need like tools, etc even the spare tire if you drive around good roads.

buy tires that are specifically meant for highway driving for pickup, they generally reduce friction and are less noisy. Though if you do drive off road, you will more likely get stuck or they will tear apart

[Islander]

I drive a '99 Ford F-150 as my main vehicle and have always liked it. Before that in our family, we also drove a Chevrolet Caprice and now a Ford Crown Victoria. Both of these cars could achieve 25 mpg or better on the highway. This is impressive, IMO, considering the size and weight of the vehicles. My F-150 gets 16-18 on the road, and this is with a five speed overdrive transmission.

In my very lay understanding, it is the rear end gear ratio which prevents the pickup from achieving similar gas mileage. Of course, it would be a matter of design that the pickup would be geared lower in order to be suitable for pulling loads. In my case, I have very seldom ever needed such a capacity.

While the gear ratio of the rear end is a factor, the body shape and size has much more influence on your vehicle's fuel consumption at highway speeds. The pickup likely has more frontal area and definitely has a higher drag coefficient than a relatively streamlined sedan like a Crown Vic or a Caprice. It takes a lot more power to push the pickup through the air and the faster you go, the more obvious it becomes.

In low-speed (city) use, the low gear ratio might actually improve the gas mileage, since less throttle is needed to accelerate the truck from a stop. Horses for courses...

[Marvel]

If you still have the rear bed open, consider a topper of some kind. If you are doing a lot of highway miles, you can cut the drag that way. I used to own a Datsun pickup, and made a cover of my own. I rarely carried large objects, so it was like a tonneau, but made out of wood. Even though I already got good mileage, it improved even more. Gas was only $ .40 a gallon though. [:|]

Many of these options will be a problem, because you will have to spend some to start saving, but there is nothing like the comfort and safety of a larger vehicle.

[Coytee]

Although I'd vote for finding out about changing the rear end ratio, I'd rather put it on the same conveyor belt that keeps that darn plane from taking off.... [:#]

[CECAA850]

If you still have the rear bed open, consider a topper of some kind. If you are doing a lot of highway miles, you can cut the drag that way. I used to own a Datsun pickup, and made a cover of my own. I rarely carried large objects, so it was like a tonneau, but made out of wood. Even though I already got good mileage, it improved even more. Gas was only $ .40 a gallon though.

Many of these options will be a problem, because you will have to spend some to start saving, but there is nothing like the comfort and safety of a larger vehicle.

I get a lot of automotive publications. One lately had a study from a wind tunnel testing facility in conjunction with a college. I believe they had 6 or 8 trucks in the study. On average, the bed "toppers" reduced the coefficient of drag about 8% and had a proportionate effect on fuel consumption. The testing was not sponsored by a bed topper company or any particular manufacturer. I wish I could find the article so I could quote with more detail.

[InnerTuber]

Good question, not really a simple answer -

Few things previously mentioned seem good.
Get a street tire. Max out or slightly overinflate the tires. Big tire/wheels bad, but your truck suspension is set up for a particular geometry and you can't put on those ole Yugo rubbers.

The topper idea appears interesting, tho I'd doubt a huge percentage increase. Seems, I saw research that compared tailgates and the conclusion was along the lines of no tailgate reduces weight. The drag affects were minor. SUVs would seem to get better than pickups by definition if it were a topper issue.

Gearing will change things. Depends how/where you drive. On one hand the driveshaft will turn fewer times to rotate the wheels. Good or bad? I'd say it depends. At some mph your engine will lug along. More stress on trannny possible too. Better on flat land than hills. Depends on the torque curve for your engine too. Depends how agressively you gear and/or drive. Most trucks I've looked at offer a basic setup and one option that delivers alternate gearing for towing.

Often this conundrum is solved with an overdrive gear. Tranny solution, not rear end.

I'd think if they could get mileage by simply changing gears the factory would offer that as an option. Now that doesn't mean you can't do it.

Unless you drive a LOT it's probably cheaper to keep the car and drive on rather than buy new. New tires, gears, topper cost X dollars. You can figure out how much you would need to drive to feel good about that spend.

Hate to say it boils down to horsepower (torque really), weight and some degree of aerodynamics. The gearing tends to facilitate moving the aforementioned along by keeping the tach at the desired rpm.

Just put some big honkin subs and mids in that ole Ford and plot the next station to fill er up at! A small nuclear reactor may be a good solution, tho you would need to add some A/C capacity.

Blow up them tires - it's good for a little. Watch out for snake oil!

[fenderbender]

This guy might be onto something!

[Daddy Dee]

Gentlemen,

Thanks for the feedback here. There's some helpful information you've shared.

One thought on bed covers, they do indeed reduce drag and I've been using one for a couple of years.

Interesting enough, another pickup accessory which has sold for years is a slotted or mesh tailgate replacement. It makes sense that even driving with the tailgate down would reduce drag. I was surprised when this was tested by MythBusters. Guess what? Tailgate up gets better gas mileage than tailgate down.

The effect, though it is counter intuitive, is that rolling turbulence above the bed (with tailgate up) serves as an air cushion over which other air travels with an effect something like having a bed cover. The tailgate down eliminates this air cushion over the bed and drag actually increases. Who knew?