Front&Rear wWheel arch ventilations/air extraction for MPG
 

Does it help if we build

Front & Rear wheel arch ventilations/air extraction for MPG
 

Does it help if we build Front & Rear wheel arch ventilations/air extraction for MPG?

wheel arch
 

Truly low drag vehicles have totally enclosed wheels.
Obviously,if you have a front engine car with front radiator,the air has got to have a pathway out.
Dr.Alberto Morelli has invested the most time of anyone I've read of to design a minimum drag cooling system at the Pininfarina wind tunnel with his CNR 'banana' car of 1978.
None of his air extractors were at the wheel houses.
The side extractors on the 1982 Pontiac Trans Am Firebird added drag.It could cost you hundreds of thousands of dollars to scientifically design these critters.And they would be designed on a case-specific basis,so what worked on one car would not necessarily benefit any different car.
I would recommend you take a cue from basjoos' AeroCivic.
http://asset1.cbsistatic.com/cnwk.1d...ide550x412.jpg

Didn't Hucho find that venting on top of the bonnet was the easiest way to improve efficiency ?
Might not be the most efficient way possible, but the best efficiency / effort ratio.

Vekke once had a set-up like that on his red Seat Cordoba - with radiator ducting if memory serves me well ?

I thought especially rear wheel arch extractions, I cannot close front wheels for now. I intend to do it back wheels sometimes later, but before that because of mercedes had backlights that extract air from under the car to back of the car. Or GM prototype had ventilations, or Porsche and Amg had vents from bumper, maybe that will help to cancel turbulence back of the car.

I have seen setup where air is taken from the front and extracted from the front of the front wheel.
I assume it is a good use of pressurized air to prevent turbulences in this area.

Seen it on Mercedes CLA and BMW 1series amongst others.

easiest
 

Hucho does show that.Ideally,you'd have an airtight extractor duct discharging the heated air at matched velocity with the surrounding flow so as not to introduce shear.And the cowl would have to be configured so as not to allow this air to enter the ventilation system,while providing a relatively high static pressure site for ventilation air harvesting.
Rain and snow baffles would have to be designed in as GM has done with their contemporary 191-mph Camaro and 200+ mph Corvette Stingray.
A cautionary note: If any radiator hose,or an upper or lower radiator manifold should rupture,the glycol coolant could make it through the hood and onto the windshield causing temporary blindness.

GM prototype
 

The 1999 PNGV GM 'Precept' has rear cooling,and the fenestrations in the rear quarter panels are air inlets,not extractors,of which are in the transom.