Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - CRX vs MX-3 aero, When aero doesn't seem to work

Cd · 10-24-2015, 09:45 AM

Here is another excellent example of what I am talking about.
Of these two cars, which is more streamlined ?
The VW Fox ( I used to call them the VW Box ) :

Or the Jaguar XJ-220 :

The Jaguar has larger tires, yes, but does it make that big a difference when the car is so low ?
Consider how many cars benefit from a full width spoiler at the front of the car. Surely that adds just as much drag as the exposed tires of the XJ-220.
There is a built in spoiler on the rear of the XJ-220, but it is very subtle, and not like the huge drag inducing ones that are frequently on high performance cars. The car is wide, but that effects CdxA, and here we are just talking Cd.

The XJ-220 even has flush wheels.

When the XJ-220 first came out, I was still under the impression that a laid back windshield was good for aerodynamics. I was floored to find out that the Fox had better drag.
And with the smaller frontal area of the VW, it was actually quite a bit more streamlined than the XJ-220.

The numbers ?
Jaguar XJ-220 point 32 VW Fox point 31.
So given the same amount of power, the Fox would actually have a higher top speed. Amazing.

I just noticed a nice little aero feature of the XJ-220 - the wheel arches have a nice smoothing out at the rear of the wheel well, much like the Honda Insight did. Also, consider that the XJ-220 has a flat underbelly since it has the engine at the rear of the car.
The rear glass is flush as well, unlike many Ferraris and Lambos.

10-24-2015, 09:45 AM	#3 (permalink)
Cd Ultimate Fail Join Date: Feb 2008 Location: Austin,Texas Posts: 3,585 Thanks: 2,872 Thanked 1,121 Times in 679 Posts	Here is another excellent example of what I am talking about. Of these two cars, which is more streamlined ? The VW Fox ( I used to call them the VW Box ) : Or the Jaguar XJ-220 : The Jaguar has larger tires, yes, but does it make that big a difference when the car is so low ? Consider how many cars benefit from a full width spoiler at the front of the car. Surely that adds just as much drag as the exposed tires of the XJ-220. There is a built in spoiler on the rear of the XJ-220, but it is very subtle, and not like the huge drag inducing ones that are frequently on high performance cars. The car is wide, but that effects CdxA, and here we are just talking Cd. The XJ-220 even has flush wheels. When the XJ-220 first came out, I was still under the impression that a laid back windshield was good for aerodynamics. I was floored to find out that the Fox had better drag. And with the smaller frontal area of the VW, it was actually quite a bit more streamlined than the XJ-220. The numbers ? Jaguar XJ-220 point 32 VW Fox point 31. So given the same amount of power, the Fox would actually have a higher top speed. Amazing. I just noticed a nice little aero feature of the XJ-220 - the wheel arches have a nice smoothing out at the rear of the wheel well, much like the Honda Insight did. Also, consider that the XJ-220 has a flat underbelly since it has the engine at the rear of the car. The rear glass is flush as well, unlike many Ferraris and Lambos. Last edited by Cd; 10-24-2015 at 09:56 AM..