Home » How Budgets Racers Built Supercar-Like Active Aero Out Of Pop-Up Headlights

How Budgets Racers Built Supercar-Like Active Aero Out Of Pop-Up Headlights

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Active aero has long been a controversial topic in the automotive world. Once the hottest new thing in motorsport, it was quickly banned in most top-flite series for safety reasons and to avoid a costly arms race. It then trickled down to the techiest road-going vehicles, and today, just about every hypercar has some kind of wiggly flap or other. You don’t need a seven-figure budget to do active aero, though. If you’re resourceful, you barely need three. That’s all thanks to the shade-tree motorsports set, which has developed some nifty tricks to do active aero on a budget, and it’s all thanks to pop-up headlights.

First, let’s talk about what active aero really is. At its heart, it refers to aerodynamic devices that can be moved to vary their generation of lift or drag. For example, many sports cars have a rear spoiler that extends when driving at speed to generate more downforce. Often, these spoilers can also be tilted up to act as an air brake, creating extra drag to help slow the car down in a braking zone. This is the most common type of active aero on roadgoing vehicles.

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In racing, a great example is Formula 1’s Drag Reduction System. It’s the only type of active aero device that’s legal in the series. This sees the vehicles use a movable flap in the rear wing, which, when opened, reduces the downforce generated by the wing while also reducing drag. This allows the cars to hit a higher top speed on the straights. Across the board, these systems are engineered with the help of computational simulations, wind tunnels, and great reams of calculation and analysis.

When it comes to the world of amateur motorsports, everything’s a bit simpler. However, despite its potential complexity, eager tinkerers have explored the prospects for developing active aero at the grassroots level. Keith from parts shop Flyin’ Miata is one such racer. His Targa Miata racecar is a fairly serious build, with a rollcage, sticky tires, and a brilliant Martini livery. Even better, it’s got a huge wing on the back with an active aero system you could build out of junkyard parts.

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Keith’s build is a simple setup capable of two positions. In its standard position, the wing is positioned to generate the appropriate amount of downforce to aid with stability and grip. Then, when Keith hits the brakes with the system enabled, the wing is pushed up and forward to act as an airbrake that helps slow the car by generating a great deal of additional drag.

The real magic is in the simplicity of the implementation. Initially, Keith had toyed with using industrial linear actuators to move the wing. These don’t always come cheap, and the parts Keith found couldn’t do the job. Those available to him were either too weak, or too slow. He abandoned plans for a three-position system that could act like a drag reduction system and an air brake. He elected to go back to the drawing board and build one with two modes instead—regular downforce, or tilted forward as an air brake, akin to the operation of the spoilers on many supercars.  In the end, the old adage bore fruit–the Miata is always the answer. Keith’s salvation was the actuators from the Miata’s pop-up headlights. They’re plenty strong enough to raise the wing, even at 120 mph, and they’re able to move from one extreme to the other in about half a second or so.

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Getting the electronics rigged up was remarkably easy. There’s nothing fancy going on; Keith just hooked up the 12-volt headlight actuators to the brake light circuit. It’s a simple on-off operation. When the brake lights come on, 12 volts goes to the the actuators, which move the wing to the high-drag position to help slow the car. When he comes off the brakes, the wing moves back down. The headlight actuators are only capable of these two extremes, but that’s enough for a barebones active aero system built out of junkyard parts. Keith considered whether this simplistic setup might be a problem, such as if it caused instability in a situation where he was on and off the brakes. Fundamentally though, he notes that when he races the Miata, he’s hard and decisive on the brakes, and it hasn’t proved to be an issue, even when modulating the pedal.

Keith notes that the main benefit of the build is the additional stability under braking. When he built the system, the car had a 350-horsepower  V8 under the hood so Keith’s Miata is plenty good at punching through the air, but it puts a great deal of stress on the brakes. The air brake is thus a boon when it comes to slowing the car down from high speed. “It’s like throwing out a drogue chute… you’re pulling on the back of the car, basically… you’re helping keep it stable,” he explains.

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It does come with some drawbacks, though. With Keith’s setup, as soon as the wing goes into its air brake position, it becomes virtually impossible to see through the rear window. That can be a problem on track if you’re under attack from behind. He also says he grew tired of people bombarding him with questions in the paddock when he went to the track, along with a deluge of unsolicited suggestions on how to do it better. Sadly, he also had data acquisition problems that prevented him from getting hard data on any actual lap time improvements. However, from a seat-of-the-pants perspective, he credits it with greatly improving his confidence in the car under braking.

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Keith isn’t the only one that’s tried this over the years. His tinkering began a decade ago, when he got the idea from Warren van Nus at Exomotive, the company which turns Miatas into Exocet race cars. If you’re a long-time punter around the Chump Car or 24 Hours of Lemons scene, you’ve probably seen others working with similar equipment, too.

It makes almost perfect sense if you’re racing in cost-limited series like these. If your Miata doesn’t need its headlights, you can just move the actuators from the front to the back of the car without taking a hit in the budget. A few bits of wire to hook them up to the brake light circuit, some homebrew hinges and linkages, and you’re golden. Your only main expense would be the wing.

The Miata Turbo forums have a great thread that talks about these kinds of builds. Robert, a Chump Car racer from Texas, noted that he built a similar setup using a single headlight motor that lasted for a full 24-hour race. His team relied on the brake light actuation method, as any kind of more advanced controller would have been against the budget constraints imposed by the series. He credited the setup with greatly improving the car’s stability under braking, particularly in the rain.

Miata Active Aero Experiment (fm Live) 9 46 Screenshot
A headlight motor from the NA Miata is a cheap and simple actuator that can be put to great use. First contraption that can cook a Full English Breakfast using nothing but Miata headlight motors wins a T-shirt, my treat.

It bears noting that you can do this on other cars; it’s not just limited to Miatas. If you don’t have a set of headlight motors kicking around, though, it can be a less enticing prospect. If you can get used ones cheap, dive in; expect new replacements to cost you $150 for one. You might be able to make something work with one, but two gives you double the power and can simplify the build. By the time you’re spending hundreds of dollars, it might be time to consider grabbing some high-powered servos and going for a more advanced design with flexible positioning. With more money, you could consider buying an off-the-shelf active aero wing. These solutions kind of lack the low-buck charm, though.

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Ultimately, if you’re looking to experiment with active aero on a budget, it’s hard to go wrong with a setup like this. Chat to your local Miata fanatic if you’re on the hunt for parts. Every city has one, I promise you; you just have to hunt for the yard full of NA shells (shout out to Ray). Grab yourself some bits, do some experiments, and see if you can score yourself a better racecar and some quicker laps to boot. Happy hacking!

Image credits: Flyin’ Miata, YouTube screenshots

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Keith Tanner
Keith Tanner
2 months ago

Kudos, Lewin. That was a well written article on my experiments and those of others. I hope we see some interesting projects come out of it!

Morgan Thomas
Morgan Thomas
2 months ago

In the late 80s, the R31 Skyline GT, GTS and GTS-X had a retractable chin spoiler that electrically extended automatically when speeds exceeded 70km/h.

William Sheldon
William Sheldon
2 months ago

despite already being an air brake due to cross sectional area/shape, i need this on my xc90. Hold on kids!

Scott Wangler
Scott Wangler
2 months ago

As the owner of a Porsche with about half the power I would be more interested in a drag reduction system. Not sure how I would actuate that though, there is lots of time I am WOT and still want the downforce.

Hondaimpbmw 12
Hondaimpbmw 12
4 days ago
Reply to  Scott Wangler

F-1 drag reduction started out with a hole in the side of the cockpit that the driver would put his hand over as he set off down the straight. Nowadays, I think they put button on the steering wheel. I’m sure a button could be rigged for the average race car steering wheel.

Beater_civic
Beater_civic
2 months ago

This is so cool! I love some budget engineering. I wonder if it’s possible to design something like this that works pneumatically or hydraulically. Basically you would just increase pressure to a piston that lifts the flaps, so to speak, in response to brake pedal travel. Just spring load it for the rest position, or let airflow take care of it for you.

Bonus points if it runs off the 12V tire inflator thing kicking around the trunk. No clue what kind of psi one of those wings sees though.

Cerberus
Cerberus
2 months ago

There are so many great parts sitting in junk yards that could be used for all kinds of clever things. When I was younger, I used to go to yards telling the guy I was getting some whatever small part and then spend a while looking at all kinds of cars and trying to think up and remember alternative uses for them.

I never built it, but I designed a drop-down airdam using pneumatic cylinders for my mk1 Legacy. That’s a different case, though, where it retracted for ground clearance reasons, but would be deployed more of the time. I also figured in a mechanical locking linkage to resist aero forces (not sure if it would be needed or not, but that and making sure to deploy it at lower speeds meant the system didn’t need to be very powerful). I planned to use the compressor from an air suspension model. Headlight motors would be a better solution. I can’t remember why I wanted to go pneumatic as this was over 20 years ago.

What causes the motor to end operation per design? I imagine there’s an internal limit switch that opens the circuit when it reaches the desired extent of travel or am I wrong? If I’m correct, I wonder if more positions could be allowed here with a set of reed switches or something to cut power to the motors with a rotary switch or something that would cut out the switches for the undesired settings, leaving just the one someone wanted to use. Say you want the air brake, but also 2 positions for downforce—a low downforce for straights and a high downforce for cornering. Set it up as they have it here with full motor travel in one direction as air brake, but with the other end of travel being the setting for minimal downforce. To get the high downforce setting, a sensor corresponding to that position could be set to trigger the power cut to the motors and limit the wing travel to wherever that desired position might be (and this could be built into a bracket that’s easily adjustable). There could be a switch in the cockpit the driver could flip to switch between the low/high downforce limit stops. Brake would still activate via brake pedal, but if the driver was coming up on a straight, they might want to flip the switch to cut out the intermediate high downforce position and vice versa for a set of turns.

Scoutdude
Scoutdude
2 months ago
Reply to  Cerberus

It does look like a bunch of wires go in/out of the cover on the opposite side of the output shaft so I suspect there are some limit switches that that shut off the power to the motor when it reaches the end of travel. So chances are you could pop that cap off and position a switch that is actuated in the mid position and connect to a relay that changes between the OE switch and the added switch. Or you could just use a window motor, which is essentially what the headlight motor is and do your own switching/relays to give multiple positions.

Keith Tanner
Keith Tanner
2 months ago
Reply to  Scoutdude

You might want some positional feedback in that case, especially if you’re using multiple motors.

Keith Tanner
Keith Tanner
2 months ago
Reply to  Cerberus

The next version of this was going to involve a three-position setup – although you could consider the air brake setting as being high downforce and the normal position as DRS. F1 cars have massive drag from their wings so DRS has a big effect, my wing is a lower drag design so DRS would not have been as effective.
Warren did a video of how the headlight motors work internally a long time ago. IIRC it’s not really possible/easy to stop them in an intermediate position. The nice thing about using them as-is is that the engineering of the motors themselves is rock solid.

Slow Joe Crow
Slow Joe Crow
2 months ago

That’s a more useful trick than the vacuum operating skulls on Murilee Martin’s Black Metal V8olvo.

Usernametaken
Usernametaken
2 months ago

I’ll never understand the upper technical echelons of racing go “We are the pinnacle of automotive technical engineering. That neato idea you had that makes your car faster that’s novel? Yeah we should probably ban it immediately because you came up with an engineering solution that made your race car faster”

It really undermines their messaging that the justification is to advance automotive engineering and technology

Cerberus
Cerberus
2 months ago
Reply to  Usernametaken

The justification has been largely marketing nonsense for a while, though it did get us the hybrid era of F1, I suppose, even if virtually none of those particular systems are used in road cars. The reason they outlaw this stuff is the same as it’s always been: cost and safety. There have been unlimited series in the past and they died off due to both of those reasons. Think the original Can-Am series, Group B rally, and Group C prototypes. Besides the cost factor, the current tracks can only accommodate so much speed and, ultimately, the meat bag behind the wheel is also physically limited in their ability to withstand the constantly changing and extreme g forces. As it is, drivers have to be pretty fit. It might be wild to see a series that had no drivers just to see what the limits could be, but very few people would watch it. I’m not a people person and I have more interest in the technical aspect than the drivers, but even I wouldn’t want to watch a series that was just remote control or AI or something.

Hugh Crawford
Hugh Crawford
2 months ago

Mercedes Benz windshield wiper motors are hugely powerful, and are found with lots of linkages in their native environment. Probably other brands are similarly over powered.

Robert M. Graham
Robert M. Graham
2 months ago

Nice article, but you didn’t discuss any of the testing procedures to determine effectiveness of the device. If I could paste a short gif, I’d show you how we tested our AARP (Advanced Aerodynamic Retardation Project) that we used in a Lemons race. We clamped it to the roof of my old Tahoe, and then deployed it going down the road. (Can’t attach any pictures either.)

It did, as Jay Lamm said in an email, “butt-ass nothing”.

TOSSABL
TOSSABL
2 months ago

Deleted comment referring to a brake Jack Beckman posted about below

Last edited 2 months ago by TOSSABL
Keith Tanner
Keith Tanner
2 months ago

This was tested at High Plains raceway in an A-B test – first with the wing fixed in place, then with it active. It can be turned on and off with a switch in the cockpit. Unfortunately, the Traqmate suffered an accelerometer failure so there was no hard data and HPR is a long way from home. The article was written based on a couple of my videos, you might find more information in the video itself.
It was also tested while going down the road – there are videos of that on YouTube. But that was just “does it really move like it’s supposed to”, not “how well does it work at 120 mph?”

Robert M. Graham
Robert M. Graham
2 months ago
Reply to  Keith Tanner

Wow! You had actual instruments? We were lucky we had a video camera! I’ll have to check out your videos.

Don’t know why I didn’t think of putting the video on YouTube … I have a channel.
https://youtu.be/2XC70gVtzNE

We tested on a Tahoe for installation on an Olds 98. We were after any help we could get for the brakes. It was activated by the airflow when we pulled a release, than springs were “supposed” to push it back down once slowed down.

Last edited 2 months ago by Robert M. Graham
Jack Beckman
Jack Beckman
2 months ago

Some of the LeMons stories: https://www.caranddriver.com/news/a18739149/lemons-goodbad-idea-of-the-week-cessna-airplane-wing-provides-serious-downforce-for-honda-civic/

My favorite though is only mentioned at the front – the bowling ball in the trunk tied to a movable wing. When you accelerate, the ball rolls back and the wing is opened; when you hit the brakes, it shoots forward and pulls the wing shut. Not sure I like the idea of a heavy object shooting back and forth behind me when I’m racing, but it’s pretty ingenious.

Alexk98
Alexk98
2 months ago

I’ve been joking since I bought it that my NA has active aero since the headlights produce more drag when open, but dang it I didn’t think I was this close to being actually correct (as opposed to only technically correct, the best kind of correct)

StillNotATony
StillNotATony
2 months ago

That is just SO cool and clever!

Mr. Asa
Mr. Asa
2 months ago

I’m a simple man. I see something Keith or Flyin Miata did, I read about it. Then I send it to my friends.

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