Wheel well vents

[renault_megane_dci]

Automotive Aerodynamics - Sport Compact Car Magazine All Pages
Extracted article from the link :

[renault_megane_dci]

http://www.youtube.com/watch?v=ymvI_h1VwgI&sns=em

[serialk11r]

Originally Posted by Oceanic815

Thinking about the vents that are on top of the fenders of Le Mans prototype cars, I did a Google search and ran in to this thread on a Miata forum for reducing wheel well pressures.

I think the vents at the top of the wheels are not beneficial, they're there as a safety measure to reduce lift in certain accidents. There was Porsche magazine that said this.

In that thread, user lightyear has a nice setup His modified fender has the radiused edge that aerohead has mentioned before.

[whatmaycome14]

Originally Posted by jedi_sol

I think the OP is talking about the vents "behind" the front wheels....

Here is what is underneath the vent "behind" the front wheel

Well, would you look at that. I can't imagine that doing much good at all.

[ECONORAM]

Has anyone tried doing an air pressure check, like was mentioned in the miataturbo forum? I might consider that, once I get some time. My truck's wheel well openings are all radiused, but I'd like more ventilation since I've got a belly panel installed. My first thought was to put a vent aft of the front tires, hoping the passing airstream would draw hot air from the engine bay. But on second thought, that may not work since the tire is blocking the airflow, and I have mud flaps (I don't like rock chips...). Would a vent on the front side of the wheel tub work? I'd think the air would be moving down towards the ground, given tire rotation, and would draw air out of the engine bay...but haven't tried to put the theory into practice.

[spacemanspif]

My reasoning for starting the thread was an idea from an observation just under the assumption that the back half of the wheel well traps air and is a parachute of sorts. Ideally, radiused wheel wells would be used like on these club cars with the back 1/3 of the flare cut off. But since paint protection is a concern for most who drive their cars more than 1x a week and not on a race track, I thought the vents would be a good alternative and possibly (if they work like I'm thinking) be a cleaner, better looking alternative to wheel skirts. Skirts would be ideal but some aren't willing to take the plunge so if you could add a vent and get 75% of the benefit as making a skirt, it could be worth it. I'm guessing that the larger the space between tire and wheel well, the more air is trapped and the more benefit could be had from wheel well treatments of all kinds. Flared fenders like those on STIs and VW beetles would be easiest to do it on, but some creative ducting could be used to adapt to any vehicle much like how BMW did it with the aforementioned vehicle.

In regards to the Jeep comment, large fender flares will catch a lot of air but to cut off the last 1/3 would mean all sorts of debris from the tires getting kicked up and hitting the body and possibly the driver. Cutting an opening and attaching down facing vents or a small-ish screen could prevent body damage while alleviating some parachute affect of the flares.

On engine cooling: those with full belly pans have to exhaust radiator air/heat somewhere. I've seen a few that do it into the front wheel wells. If the pressure in the wheel well is high, then it could prevent some cooling as the max amount of air isn't being allowed over the rad. Venting the wheel well at the rear could possibly help maximize cooling as well if it drops the pressure substantially, Right? Otherwise a fender vent connected the engine bay would be needed (assuming the engine bay is completely sealed off)

[Oceanic815]

Something else to ponder, courtesy of Ferrari. These obviously would not work in combination of a mud flap or stone guard, but here we go:

The area behind the wheel of a 599XX Evo:


I had the fortune to view one of these 599XX Evos at the 2012 Rolex 24 at Daytona that was on display. Also on display was a 333SP which also has a front fender treatment, similar to the one shown below:



Going back to a stone guard, note the 333SP has clear plastic or curved plexi to protect the paint from rock/dirt/tire debris; this could be worth considering should one go this route.

[whatmaycome14]

Originally Posted by Oceanic815

Also on display was a 333SP which also has a front fender treatment, similar to the one shown below:



Going back to a stone guard, note the 333SP has clear plastic or curved plexi to protect the paint from rock/dirt/tire debris; this could be worth considering should one go this route.

Interesting. Does this example works best with a rear engine car, or if like in the case of the Miata, the configuration of the engine doesn't make a difference and the is just the BEST way to get airflow out of the front wheel wells.

I wonder also how having front wheel skirts would affect the entire concept?

[spacemanspif]

The 599 appears to be front engine as evidenced by the exhaust pipe. Wheel skirts would eliminate the need for the "rear of well" treatments because it would eliminate the trapping of air in the area. Vents could be a close sibstitute to the major cut outs of the race cars is my thinking.

[aerohead]

I'm not certain that the wheel well aft of the tire catches any air at all in the context of a parachute.A parachutes drag is created from the all-separation,enormous turbulent wake above it.
A pool of dead air may just travel along with the quarter panel,as with a rear bumper,with the active flow just ricocheting off the dead air.