Do FLUSH mounted window vents help aero?
 

I mean really slim flush mounted window vents that don't protude out of the window frame beyond the plastic thickness i.e. they are flat and don't curve out.

Do they actually help or hurt aero?

Vent windows??

http://oldcarandtruckpictures.com/Er...VentWindow.jpg

Flush mounted stuff usually helps aero. Whether you'll notice an improvement in fuel economy numbers is a whole other story though.

They may well be done for noise reduction as much as aero / fuel gains.

BMW did a lot of aero testing for their external mirrors to reduce noise and ended up adding "dimples" to the section between the post and the mirror.
There was probably some aero gain but BMW never claimed any.

Peter.

Not quite sure what vents he means but usually the spot right behind the a-pillars is nasty anyway... I'd think that whatever doesn't add to frontal area there wouldn't hurt or help.

It almost sounds like you are trying to describe a naca duct.

vents
 

a photo would help.

I think he means wind deflectors

http://lh3.googleusercontent.com/pub...uKwfFvWMuX9Dgg