Scirocco vs Rabbit Cd numbers

[Bildon]

I have had this in my head for years and have just recently found the #s in print again.
I know there is a general belief that the Scirocco is more aerodynamic but I was pretty sure they were not.
Here are some #s to suggest they are about the same. Not sure of the source but it was from a list of 100s of cars so I'm guessing it was compiled from something legit.

Car Cd
VW Scirocco I to-81 .42
VW Scirocco II 82-on .38

VW Rabbit to-83 .42
VW Rabbit-E .38
VW GTI to-83 .40

VW Golf 2 85-on .34

Thought some people who were desparately searching for a car might find a Rabbit quite a bit easier to find.

Other tidbits

VW Corrado 88- .32
VW Golf 3 92- .30
VW Golf 4 99-04 .31

[Dave Zaslow]

Another point of reference:

http://www.mayfco.com/volks.htm

Dave Z

[Bill Miller]

Bill,

I remember seeing Cd numbers on Rabbits and Sciroccos years ago, and was surprised at how close they were. I am curious though, what was different about the bodywork on a Rabbit E?

[JimW337]

And don't Scirocco's weigh more? Not sure if that means a whole lot with min. weight.

What's a Rabbit-E?

The GTI has a better CD, must be the little bumper filler strip in front of the grill. Arn't those Germans clever!

JimW

[joeg]

I still think the Scirroco is a much better looking car!

[Bill Miller]

I still think the Scirroco is a much better looking car!
[/b]
:023:

[itracer]

I still think the Scirroco is a much better looking car!
[/b]

Me too! And it just feels faster :035: I may be a little biased though.

[dickita15]

don't you have to multiply the cd by the frontal area. is the roofline lower on the scirroco lower?

[shwah]

don't you have to multiply the cd by the frontal area. is the roofline lower on the scirroco lower?
[/b]


I am glad you brought this up. The Scirocco has an advantage in frontal area, the CD is close enough that it will still take less power to push through the air.

[Bildon]

>> it will still take less power to push through the air.

Given the same weight etc etc

The #s I found didnt have area figured in for the Scir.
Wish Dave's site had the old Golf/Rabbit figures.

Rabbit E is the "Formel E" I think it just had skinny tires was lighter and had A pillar fairings.

Ok so perhaps the jury is still out ... the important thing is that my Corrado is the most aerodynamic VW :D

[JamesB]

Only if you ignore the mk3 ;)

[Eric Parham]

I'm liking that '90 Passat GL... 0.31 Cd BABY! Mom had a wagon. Not a bad car except it often overheated when driven hard -- NO grille, you know.

In all seriousness, though, I think frontal area has a lot more to do with race car performance than stock Cd. Airdams/splitters/diffusers can make a huge difference in Cd. Also, the stock Cd #'s are with all WINDOWS CLOSED. I have yet to see published Cds with windows open. I'm sure the window issue alone has vastly different effects on different cars. Mirrors are yet another variable...

[Wreckerboy]

I'm not an H20 VW expert by any means, but I *think* that the Rabbit E model was a stripper, carbureted Rabbit. (I remember seeing one at the dealership when I purchased my first new car, a '84 GTI, at Walters-Donaldson in Hicksville, NY)

[Bildon]

Eric, You're absolutely correct. I shouldn't post after midnight. :P

>> the stock Cd #'s are with all WINDOWS CLOSED.

Think anyone else will notice that my power windows (yes they still work!) are wired into the rear wing relay???
:D

[msogren]

Drag is CD X area. The Rocc is a lot cleaner aero wise. It also has the vent windows and smaller glass openings. The lower roof also gives it a lower Cg and results in a faster car than the Rabbit. But the Golf is as good if you factor the 12 hp advantage . BUT, The Jetta is the best aero wise. weight wise. it carries 20# less LF weight than the Golf and the trunk is a lot cleaner than the hatch.
Jettas rule the aero data, but I can get more tires into the back of the Golf>>>
MM

[JimLill]

Cd alone is not the aero answer. Effective frontal area is what is pushing the air. You have to take the cross-sectional front on area of the car and then apply the Cd to get effective frontal area.

To measure that and be accurate, you need to consider green house taper, and mirrors...

So for a A2 GTi you might get around 19.5 sq feet cross-section, with an effective frontal area of 6.63 sq ft