VW Beetle Aerodynamics

Have any of you ever thought about the aerodynamics of a VW Beetle? Getting closer to playing in the Road Course/Auto Cross world of Racing I’ve been thinking more of it as of late.

I come from a Drag Racing background. Sure we’ve talked about our cars and how they have the aerodynamics of a “Beach Ball” going down the dragstrip, lol! That’s why most of us who race drag bugs use some sort of spoiler or engine cover. It’s somewhat decoration but also does provide down force that is important to the performance of these cars.

A good friend and fellow VW Drag Racer “Larry Kelley” once told me that a small pitch on the wing of our bugs would create badly needed down force necessary to plant these cars to the pavement. You see Larry had spent time in actual wind tunnels studying the effects of this exact issue. His car, the “Cal-Look Express” actually has a pitch to the wing (forget the exact degree) and it works to perfection. Another good friend and long time VW Drag racer “Dunebuggy Dale Adams” has his “Dale Adams Racing” bug and his wing/engine cover covers the entire back window. If you were to put these VW’s in a wind tunnel you would see how the wings act as “spoilers” and help to plant the vehicle.

Now of course with “Bumblebee” that would seem a bit “extreme” considering this car is built for running around a road course or auto cross track. While planting the car is important, keeping the engine cool is too! The Drag Bugs are making 1/8 and 1/4 mile passes whereas Bumblebee will be running laps and driving down the highway.

The car will have a potent power plant in the form of a 2258cc Stroker Engine with 48IDF’s and a Bergmann Porsche Fan shroud kit. This should be more than adequate for dispersing extreme amounts of CFM needed to cool the heads and keep this machine at a good operating temperature. With the addition of an external oil cooler and thermostatically controlled fan, the engine cooling aspect should be taken care of.

When I started investigating “German Look” VW’s I started noticing the track level VW’s were using some rear window spoilers. Now who am I, as a noob to this scene of VW racing, to question why these were installed and being used. However, I was curious as to what the exact reason was. I knew it wasn’t pure aesthetics, there had to be a reason, and knowing the rough aerodynamics of these cars I started searching!

This led me to a website by the name of Gerrelt’s Garage (www.gerrelt.nl) and his investigations into Beetle Aerodynamics. Please feel free to copy and paste his website into another window and read his findings. He has performed some great experiments and gives great insight into these great little cars. Here’s a link to his page on Beetle Aerodynamics http://www.gerrelt.nl/section-aerodynamics/aerodynamics-roofspoiler-explanation

If you’ve clicked on the link and read his findings you will see that a tiny spoiler at the top of your rear window does help tremendously. Having had the privilege of being around some very smart and seasoned VW Drag Racers I’ve learned that these cars actually create lift in the rear when higher speeds are reached. There are more intelligent people who have spent many more hours on making these great cars just a little better in performance and comfort and I trust their effort. There are a few other examples out there still available for these cars if you’re looking for a different look, function or approach. One of my favorites is the “Herrod Helper” wing. So simple yet so effective it’s a great addon to your VW.

Another popular item was the “whale tail” spoiler that replaces the aftermarket decklid. This particular item (from what I’ve read and heard) helps to allow much more fresh air into your engine compartment while also creating down force.

For now, according to my investigation and findings I’ll be installing my rear window spoiler soon and take it from there. All thanks to Gerralt and his findings convincing me what I already had a hunch on but needed the data to back it! See you at the track soon!

_{*Note – JLR Racing does not know Gerralt nor have we ever communicated on any level. His findings are unique to himself and it should be noted this is no recommendation to install any aftermarket parts or an attempt to sell anything. JLR Racing has no affiliation with any manufacturer of any products listed above and sells no products.*}

Author: JLewis