Experiment: smooth wheel discs tested A-B-A - 4.6% mpg improvement @ 65 mph

[Xist]

Originally Posted by radioranger

how about suicide doors and a continental kit LOL on a ford escort, OK I'll do it .

The spare tire cover? I once saw a [then] newer car with fake spare tires on each side of the hood, but donut-sized, with portions cut out to fit.

It has only been three days, but Atilla has not answered any of these nineteen responses.

I just drove to my parents' house, 164 miles each way, up and down hills, and through canyons. The only time that I used my brakes was in-town, or when someone passed me too closely. I coasted in neutral where I could, stayed in gear when necessary, and downshifted a few times. The only hill on which I used my brakes was entering town. Descending, turn a corner, the speed limit drops, and you see photo radar ahead.

I doubt that using pizza pans would make me so aerodynamic that I could not maintain a safe speed in any gear.

[radioranger]

I've started using the AC for braking, just flip it on max get a boost of cool aire turns the fan on for a bit and slows the car quite a bit,

[radioranger]

have to do a lot of braking to cook a pizza on that pan

[ECONORAM]

I have tried a few flavors of material. Clear packing tape (doesn't stay long at 32*), cardboard, corroplast, and LEXAN. The corroplast worked fine, but you can't see the wheels... 0.100" LEXAN cost me $90 for a 4x8 sheet, and I got 8 covers out of it. The RAM's wheels are 20inch, so 8's all I could squeeze out. I've also tried 0.020" LEXAN, but it is not strong enough to withstand the aero forces present at the front wheels. I lost one last week while driving 70 into a strong headwind. 0.100" is a bit stiff, as it it hard to get the straps around the wheel spokes and fed through the covers. I might try some .050" if it bothers me too much.
One thing to remember. I also learned to stick some foam window insulation strips to the back side of the covers where they contact the spokes...to keep from tearing up the surfaces.
[edit] I did an informal test about 18 months ago on I-44. Had a crosswind and thought the covers were giving me a vibration problem. So I stopped and removed them. Once rolling again, I found I had to slow down 5 mph to maintain the same fuel economy. I was getting 16.5mpg at 70 mph with covers; 16.5mpg at 65mph without. Rough math says that's about 7%.

[t vago]

I decided against using shrink bags and stretch wrap.

Instead, I went with construction wrap, Gorilla tape, and staples.

Left rear wheel (#3)


Right rear wheel (#1 - prototype - staples only)


Right front wheel (#2 - first to use Gorilla Tape)


Right front view


Left front wheel (#4 - one plastic support snapped off within the underlying aftermarket wheel cover)


Preliminary results indicate about a 6% gain in FE.

[elhigh]

Originally Posted by radioranger

I've started using the AC for braking, just flip it on max get a boost of cool aire turns the fan on for a bit and slows the car quite a bit,

I do that too. The wife doesn't care for full cooling even in the hottest weather, saving the AC for downhill parts of our homeward commute keeps me from melting and her from freezing. Works out pretty well.

Even better would be a variable speed, electrically driven compressor, rather than controlling the cooling by mixing in heater function. That's got to be the most wasteful way of mitigating the cooling I've ever heard of...

[AndrzejM]

Nice caps t-vago! Interesting idea

[pjbgravely]

Thanks for all the great ideas. I will probably make mine out of ABS.


As for the brake cooling issue, The best way to cool brakes is to remove the inner splash shield and run a duct from the front that blows on the calliper. Most of your cooling comes from the back side of the wheel.

Before the days of huge alloy wide open wheels so everyone could see how big your brakes are ( except now they just leave the stock brakes) most cars and trucks had steel wheels with small holes for weight reduction.

If you don't know how to drive you can fad the brakes on any vehicle.

[Frank Lee]

...most cars and trucks had steel wheels with small holes for weight reduction.

As far back as 1959, GM was touting brake cooling vents in their steel wheels and full wheel covers.

[pjbgravely]

And those brakes were drum brakes, a different animal as the cooling is on the side and front of the drum and not the inside to the back like most front disks.

Usually I look at what GM did to solve a problem, do the exact opposite and solve the problem , no wonder they went bankrupt.