How can you tell if your car has these or not? Does anybody have a pic of what they look like? I searched but i couldnt come up with much info. Thanks.

 

look under the front of the car... if you see a big black plastic urathane peace that covers from the bumper to a little bit past the axels, you have the diffuser..

 

I think he's referring to the ones that come with the trunk spoiler. See this link, page 2 has good pictures.

https://g35driver.com/forums/showthr...t=air+diffuser

 

Did your car come from the factory (not dealership) with a spoiler? If so, you should have them. Only one way to find out for sure. Jack up your car and take a look underneath. Be careful not to break a nail.

 

Look under the car, in front of and behind each rear wheel. There's a irregular shaped plastic piece near each end of the torsion bar. There's also two differently shaped plastic pieces up and behind each wheel, aft of the A-arms. No, I'm not talking about the splash guards.

I bought my set from Grubbs but they don't carry them anymore. There were pictures on this forum.

 

now that we know where they go, WHAT DO THEY DO!!! !

 

In theory, they reduce the air turbulence under the car that might cause underbody lift, basically smoothing out the open pockets that can trap air. In practice though, you'd have to be going at a very high speed to notice any difference.

 

^^^ correct +...
The coefficient drag is reduced a little with the factory aero pckg compared to non aero starting on 06 coupes.
Reason for different design rear wing and adding under-body diffusers.

 

Yup, I believe the Cd is reduced by .01 from .29 to .28. We all know though that the aero package is bought/sold for cosmetic reasons. The stats are just marketing schemes to lure you into buying the package.

 

yeah.....I think that only aerodynamic improvement was an 0.1 improvement in Cd around my pen as I signed the sales contract......

 

dang, what a drag.

 

 

What's funny is that the sedan (1st gen) has a better Cd than the coupe. The sedan was spec'd at 0.27 and with spoiler 0.26.