What are those Diffusers on the back of GTP cars?

[Tom and Vipers]

The GTS-R concept car has then.

They appear to force the bottom flow to difuse more completely than just letting it exit the rear of the car. The increasing cross-sectional area, if "boxed" in laterally, would diffuse the air creating downforce.

I read that there was some Ferrari or Lambo that had a computer controlled variable geometry for the bottom flow - they had ramps in the flow channels so they could change the CS area.

Anyhow, what is the proper name for this things?

Thanks

 

[GTS Dean]

The bottom of the '03 is completely flat from front to rear. The diffuser is there to control wake turbulence and rear lift at high speeds. The CART Champ Cars are highly regulated on diffuser area to control ground effect downforce.

 

[Tom and Vipers]

That's what I figured it did - it works just like a wing except under the car.

And did I guess the name correctly (diffuser)?

I think that would be so cool to run on the street! The GTS-R Concept has one in carbon fiber and it looks awesome.

Nothing like scraping the back of a Viper along with the front!

Thanks for the info!

NOTE: Now there is a topic - ground effects and aerodynamics. Boy there isn't much discussed in the normal channels. If you are serious about adding these to Viper and are concerned with performance and not looks - I have no idea where to start looking for performance info on various configs.
(other than the Internet of course!) Of course at Bonneville, that stuff is the secret stuff anyway and that stuff is nearly impossible to ferret out of people....