Covering upper halves of rear wheels

[ziddey]

I know this is one of the aero mods people do a lot so I apologize for starting a new thread instead of searching around more (strike me down). But I'm planning a drive cross country soon and figure this would probably be a quick and easy mod I can do beforehand. The car is just a vw fox sedan. I figure I could get a piece of ****metal or something and drive some screws in. Since it'd be completely highway driving, I'm hoping it'd bring me maybe 1-2mpg? Am I being too optimistic? And how much should I be aiming to cover? Would ****metal be too thin and invoke too much turbulence that it'd not be beneficial? I doubt that part, but figure it's may be taken into consideration.



Actually, how about a piece of leather or something like that? I figure it'd be easier to fabricate and I could probably just leave it on full time, vs sheetmetal would look like garbage unless I molded it later on and painted it to match.

[GasSavers_BEEF]

depending on what you have done to this point, I would air up your tires to side wall max and use the "SHEET" metal to cover your grill (or at least part of it) those seem to be the first two things that most peope do with great success.

good luck on your choice.

[ziddey]

Thanks. I've already got my 35max's running at 44. I figure they're cheap enough tires to run out the middles due to overinflation. Next time around if I still have the same car, I'll step down to 155's from the 175's I currently have.

So rear wheels aren't anything night and day? The front grill is already fairly small, and the radiator is mounted to the side in the car anyway so I could cover up the grill. The valence under the front is a big issue though but I don't think I'd be able to address that before the trip.

[GasSavers_BEEF]

if you check my garage, you will see that I have completely covered my grill. the only thing I have left is the gap between the hood and the bumper and I have used weather stripping to cover most of that. I am left with an opening about 1.5 inches by about 5-6 inches.

it also depends on where you live. If you see 100 degree days then maybe you want to rethink it. where I live, high 90s is about as high as it goes and they are few and far between.

also, only do what you are comfortable with. if you are taking a long trip, I wouldn't want to experiment on the trip because if you find problems with your setup, you probably want to be close to home.

good luck

[theholycow]

I know you want fast information, so here's a search that has it:
http://www.google.com/search?q=site:...rg+wheel+skirt
It's faster than waiting for people to respond.

I'd say if you just want to do something temporary for your trip, try to find a piece of Coroplast large enough for the job. It is easier to work with than sheet metal and if it blows off it won't damage the car behind you. You might need to add one or two bars of metal to stabilize it; I'm thinking that a piece of C-channel from a drawer slide could bolt right on.

[Jay2TheRescue]

For a temporary grille block why not use duct tape? It's cheap, quick, and easy. Plus if the car does start running hot you can pull over and remove 1 or 2 strips.

-Jay

[ziddey]

Thanks! Duct tape sounds brilliant!! I'll definitely do that.

Also, I'm a little curious. What would happen if I did a piggyback system to add dfco to my manual fuel injected car? Possible? Specifically, vw digifant.

I figure, as is, if I'm coasting, I can keep it in gear and flip the key down a notch, and bring it back as needed. Obviously, there's the drag from being in gear, and I'd be better off in neutral, but that'd only be practical for long stretches of downhill where I'd be wanting to coast, vs dfco coming into play anytime I'm off the throttle while in gear.

I figure since I have a throttle body sensor, I can tap into that signal. Then, if I can tap into the rpm, and create a relay so that electricity is only supplied to the injectors when the tb is closed and rpm is over a certain speed.

But with that kind of setup, I'd need an on/off switch since it wouldn't let me rev the car in neutral without it cutting itself out. I wonder what an easy way to detect if it's in gear or not would be. Plus, perhaps I'd want to install a sensor to tell if the clutch is fully released or not.

[Jay2TheRescue]

Originally Posted by ziddey

Thanks! Duct tape sounds brilliant!! I'll definitely do that.

Also, I'm a little curious. What would happen if I did a piggyback system to add dfco to my manual fuel injected car? Possible? Specifically, vw digifant.

I figure, as is, if I'm coasting, I can keep it in gear and flip the key down a notch, and bring it back as needed. Obviously, there's the drag from being in gear, and I'd be better off in neutral, but that'd only be practical for long stretches of downhill where I'd be wanting to coast, vs dfco coming into play anytime I'm off the throttle while in gear.

I figure since I have a throttle body sensor, I can tap into that signal. Then, if I can tap into the rpm, and create a relay so that electricity is only supplied to the injectors when the tb is closed and rpm is over a certain speed.

But with that kind of setup, I'd need an on/off switch since it wouldn't let me rev the car in neutral without it cutting itself out. I wonder what an easy way to detect if it's in gear or not would be. Plus, perhaps I'd want to install a sensor to tell if the clutch is fully released or not.

Glad to be of help with the roll of duct tape... Remember, if you can't fix it, "duck" it. Chances are if you have a fuel injected car it already has DFCO, no matter what transmission it has.

-Jay

[ziddey]

mine doesn't :\

[theholycow]

I wouldn't expect it to be easy to add DFCO. It's usually done in the computer that controls the fuel injection.

You could install a fuel pump kill switch or a switch that cuts off the fuel injectors, but it's not going to behave like DFCO.

I had to google Digifant to see what it is...
http://members.tripod.com/~fuelie/intro.htm
Looks like there's some good info there.