Wheel well vents

[spacemanspif]

I'm loving some of the things BMW did with that 4-series. The back has a small kammback it looks like, aero wheels, grill shutters AND the vents that were the reason why I started this thread. If anything, I think BMW proved my idea that cars with some kind of fender bulge might benefit from a small hole cut in the rear of the bulge. Ideally this would be experimented on a car with an already messed up fender from an accident or small animal impact. Something tells me that this won't increase MPG by 500% but I wonder if it's something that might show increases outside of the normal noise if checking MPG...

And could maybe be a more simple, more attractive mod than front wheel skirts that nets almost the same gain...maybe??

[Smokeduv]

Apparently, Subaru are using them too, as well as the frontal deflector(?) to guide the air to the sides.

Thanks to kach22i who posted the image on the "Random Wind Tunnel and Smoke Pictures" thread

[whatmaycome14]

Originally Posted by Smokeduv

Apparently, Subaru are using them too, as well as the frontal deflector(?) to guide the air to the sides.

Thanks to kach22i who posted the image on the "Random Wind Tunnel and Smoke Pictures" thread

The far upper right image suggests that the wheel well vents are NOT purely cosmetic. The question remains though, is it beneficial for fuel economy...

[jedi_sol]

Originally Posted by whatmaycome14

The far upper right image suggests that the wheel well vents are NOT purely cosmetic. The question remains though, is it beneficial for fuel economy...

i still find it hard to believe the front vents have any aerodynamic benefit.

i popped off my front vents on my Sti... there is only a single 2" diameter hole behind that vent. i doubht that 2" hole is big enough to cause 3 arrows of air to flow out of that vent

[spacemanspif]

Originally Posted by jedi_sol

i doubt that 2" hole is big enough to cause 3 arrows of air to flow out of that vent

I this the new version of the "10lbs of crap in a 5lb bucket"?? lol

I can't imagine that "normal" cars would need much venting of the wheel wells, so the 2" hole might be enough to relieve any high pressure building up in there. Again, I don't think that there would be impressive gains made but it might be something to think about doing.

[renault_megane_dci]

The idea is to use high pressure from the front to offset depression from underneath.

Wheel well vents, now that I think about it might only work as one way exit only.

Excess pressure might leave through sides of the tires anyway ...

[oldtamiyaphile]

Originally Posted by jedi_sol

i still find it hard to believe the front vents have any aerodynamic benefit.

i popped off my front vents on my Sti... there is only a single 2" diameter hole behind that vent. i doubht that 2" hole is big enough to cause 3 arrows of air to flow out of that vent

Your car is an older model though. It looks to me like the vents are intended to provide an air curtain over the front wheels (which you wouldn't need if you had smooth wheels...).

[oldtamiyaphile]

Originally Posted by spacemanspif

Ideally this would be experimented on a car with an already messed up fender from an accident or small animal impact. Something tells me that this won't increase MPG by 500% but I wonder if it's something that might show increases outside of the normal noise if checking MPG...

I'm thinking of trying this on my Wrangler's plastic fender flares before I fit new wider ones. It seems like given the air gap to the tyre an aweful lot of air could get trapped in there, esp. the 7+ inch wide ones. I could even try a little 'CAD'. The problem is the flares still need to stop rocks and mud from being ejected out the back.

[jedi_sol]

Originally Posted by oldtamiyaphile

Your car is an older model though. It looks to me like the vents are intended to provide an air curtain over the front wheels (which you wouldn't need if you had smooth wheels...).

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

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

[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.