The vast majority of racing series in the world have some level of restriction on aerodynamic elements. Take that away, though, and you get truly wild cars, like this Audi S4 from aftermarket shop JXB Performance.
As seen on its Facebook page, the company’s self-proclaimed “biggest project yet” has a 4.0-liter, twin-turbo V8 from a 2017 Audi S7 under the hood. With the help of twin turbos plucked from an Audi RS7, it’s tuned to deliver 650 horsepower. It sports a mighty five-element wing on the front that sits proudly ahead of the front bumper. There’s another five-element wing at the back too. Despite its size, the huge aero package only adds about 250 pounds to the car’s weight.
Don’t get confused by the fan at the rear, though—that’s not for downforce. It’s just for cooling the air-to-water heat exchanger and it pulls air from above, not below.
The car also features many parts from the JXB Performance catalog. The suspension is fully kitted out with all spherical bearings, including spherical strut tops, and there’s a performance two-piece driveshaft carrier too. The front and rear diffs are running helical LSDs, and the manual six-speed shifter has been heavily upgraded for a gated-like feel.
Fully race-prepped, the car had shed 800 pounds of weight over stock before the big wings were added. That’s in part down to the carbon fiber front fenders, trunk lid, and sunroof delete panel.
The aim was to generate major downforce with plenty of tunability. With such large elements and so many of them, there’s plenty of adjustability here to get the levels right at both the front and rear. As a bonus, such large wing elements are often particularly useful at generating high downforce at lower speeds.
In an earlier, less-radical iteration, the car has competed in various SCCA autocross events. It was originally prepped for the Street Modified class.
The new aero package was built in a hurry for the UMI Performance King of the Mountain event, an autocross contest with unlimited aero rules. With a five-figure payout for the winner, the big wings were inspired by a simple ethos: “what aero would it take to win while carrying a two-second cone penalty?”
From reading the rulebook to fitting it to the car, the wings were built in just six short weeks. Formula SAE papers were used as a guide to the development of the package.
Early testing revealed an excess of rear grip, hardly a surprise given the size of the rear wing. Tuning the wing to the proper level was as simple as removing a couple of elements to get the balance right.
We look forward to seeing the Audi S4 on track. Standing eight feet tall at its highest point, it should be pretty difficult to miss. Let’s just hope that the wing struts hold out.
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