Micro-mini Wheel Skirts

[lunarhighway]

a few 80's and early 90's cars wich had quite good to exeptionally good Cd's used these cut off rear arches... unfortunately big wheel arches again became a fashionable in the late 90's and this smart feature disapeared.
here's a few examples of car wich more or less cut off rear arches... most have pretty great aero for their age


1986 opel omega 0.28 Cd (one of my favourites)

1984 opel kadett (later rebadged daewoo nexia and pontiac lemans) 0.32 Cd

1983 citroen bx 0.34 Cd

1986 citroen ax 0.31 Cd

1996 Smile (greenpeace converted renault twingo) 0.25 Cd (compared 0.35 for the original twingo)

[Xringer]

Wow! Those are some neat pics! I'll bet that any blockage at all helps
keep the air flowing the down the side of the car smoother..

The massive hole above my wheels is exposed to the side air rushing by..
If it was high pressure air or low pressure air, it seems that either would
disrupt the air flowing down the side of the car.



I think just about anything would help this situation. But the scangauge is the final judge.

[Xringer]

The back skirts are close to the tires, but are doing okay. But the front ones are getting worn down in the middle a little when I do turns in parking lots.
I'm gonna have to trim a little arc in the middle of them and they are
going to be really ugly.. (Or, maybe my wife won't notice)..

[Sean T.]

Those miniskirts look really good... I think you should definitely try using a metal brace and making a full rear skirt. The way the gray trim is shaped, your car definitely has the potential for it.

Sorry to be off-topic, but do you have aftermarket headlights or something? They just don't look right for some reason...

[Xringer]

Originally Posted by Sean T.

Those miniskirts look really good... I think you should definitely try using a metal brace and making a full rear skirt. The way the gray trim is shaped, your car definitely has the potential for it.

Sorry to be off-topic, but do you have aftermarket headlights or something? They just don't look right for some reason...

I was looking for a zero drag profile, so I went with flat, instead of having the budge sticking out. It seems like I've got 50 to 60 percent of a Full skirt, so I'll try this for a while and see what happens.

The headlights are standard OEM. Here's a different angle.

Haha.. They still look a little weird..

[SVOboy]

I like it! It's not ideal, of course, but it's better than nothing and looks pretty neat, especially with the rim treatment,

[groar]

Originally Posted by lunarhighway

1996 Smile (greenpeace converted renault twingo) 0.25 Cd (compared 0.35 for the original twingo)

Thanks for this picture, I never saw this twingo.
Here are 2 links I just found with info and pictures :

• Greenpeace - SmILE
  see at least Technical Specs and Pictorial
• Twingo Greenpeace

The engine is a 358 ccm and weights 35kg !!! It consumes 3.3 L/100 km (71mpg) instead of 6.7 L/100 (35mpg).

Denis.

[Concrete]

Xringer,

looking good
and I would not worry about increasing drag by catching airflow with the mini skirts
judging by Lunar's post you are in good company

but to crexcrex point I bring my own failed test data of full skirts
I did a quick test with scan gauge at 65 mph the cover shown below
they were at best no improvement & I do believe, as crexcrex said

trap the turbulence and cause more drag.

but...
I have open wheel wells in front of and behind my rear tires
(my truck bed is sort of hollow looking in that area)
I believe I was catching air from under the vehicle & not letting it equalize thru the wheel opening

you appear to have closed wheel wells - front and back
I predict you will be gaining on this mod
measuring it might be an issue if you don't have instrumentation

Hope this helps
waiting to see your results
might mod my card board wonder skirts to match

[Xringer]

Originally Posted by crexcrex

One can easily note that there is a roof rack in place not to mention the extra weight, i would think that eliminating the drag from the turret might be an idea.
The rear spare, how many pounds are there bieng given a free ride plus the wind turbulence the spare causes.

Mods may well be fine and dandy but i do think that the obvious is bieng overlooked............

I am only expressing a opinion that you may well dismiss as bieng trivial, mods are great as long as one does not overlook the obvious

I did some yarn testing the other day. I taped three 6 inch pieces of yarn
on top of the spare so I could see them fly around as I zoomed up US95..

Didn't happen.. The three yarns just lay there like they were asleep.
Maybe my Coroplas Spoiler and Wake Boards are blocking the spare.?.

I moved the yarns to my rear window. I'm starting to think that's going
to be a low turbulence area too.

[Blue Bomber Man]

I think even partial skirts would be an improvement, contrary to what crexcrex believes. The logic he uses states that air gets trapped up there with no escape and thus must create drag, so presumebly a full skirt would be even worse by this logic.

The partial skirts certainly must improve laminar airflow some and I think it is a good compromise for those that do not feel a full skirt is practical.