Cd of 2011/2012 Jetta TDI

[mspropst]

Hi,

I'm new to the eco-modding world and I wanted to get a Cd value for my car to start with at stock. Also, how to calculate changes to the Cd (I know, I'm really REALLY new to this). The car is a 2011/2012 Jetta TDI.

It's not listed in the list sticky above, so I figured I'd ask and see if anyone knew.

Thanks.

[Cd]

Volkswagen has a world class wind tunnel that they use to test all of their cars.
Information like that is usually pretty easy to come by. Sales brochures usually have that information.
Have you already looked online ?
I seem to remember it being either .28 or .29

[Angmaar]

The cd is 0.30. Source

[Cd]

Originally Posted by Angmaar

The cd is 0.30. Source

Somebody in the VW aero department is getting lazy it seems.

[euromodder]

Originally Posted by Cd

Somebody in the VW aero department is getting lazy it seems.

That's what Hucho says. Aerodynamic improvements have come to a standstill as they're not important when testing is only done at an average of 32.5km/h / 20 mph.

[mspropst]

Anyone know of a place you can see the aerodynamic flow over a car as it is stock? Or is that only something they put on commercials to sell to you? May be a dumb question, but I'm curious as to where the aerodynamic problems actually are located at.

[Arragonis]

Have you seen the flow illustrator ? If not search for it. It is cool.

As per your other thread on mods look at what the Bluemotion models have over yours. Don't slap on a bodykit (weight) without checking the benefits first.

[mspropst]

Pretty cool. Checking it out right now. Trying to figure out what numbers to run on it for highway speeds with my halfway decent cropped out Jetta bitmap.

[Cd]

Originally Posted by mspropst

Anyone know of a place you can see the aerodynamic flow over a car as it is stock? Or is that only something they put on commercials to sell to you? May be a dumb question, but I'm curious as to where the aerodynamic problems actually are located at.

Smoke testing like you see in the commercials is pretty much just for pretty pictures.
An SUV will 'look' streamlined in a smoke test, but is actually quite the brick.



Compare it to a car that is actually streamlined :



Looks almost the same doesn't it ?

If you really want to see what the air is doing around your car, you can try tuft testing it like this :

[Cd]

Originally Posted by mspropst

Pretty cool. Checking it out right now. Trying to figure out what numbers to run on it for highway speeds with my halfway decent cropped out Jetta bitmap.

The Flow Illustrator tool is nice, but will not show real world results like the vortexes that show up around the sides of the car, or other problem areas like under the car.