Journal: This Is How Turbofan Wheels Evolved From Racing To The Street

This Is How Turbofan Wheels Evolved From Racing To The Street

Petrolicious Productions By Petrolicious Productions
July 7, 2016
14 comments

Written by Alexander Sobran

Do you remember any periods in your life wherein some nascent but compelling interest managed to imprint itself on every facet of it? Maybe speak like Yoda you did after seeing Star Wars, perhaps a Pokémon backpack to hold your Pokémon lunchbox and your Pokémon Trapper Keeper. Forget embarrassing fad worship, though, because the same dynamic is responsible for one of the most polarizing and unique automotive innovations both on- and off-track: turbofan wheels.

What was the spark for this radical idea—to put bladed covers over wheels to aid in brake-cooling? It was the dawn of true aerodynamic understanding applied to the best sport there is: car racing. What still boggles many minds is just how long this took to happen, this great “catching up” of aero to engines. What I mean can be summed up by the fact that humans managed to supercharge inline-8s decades before they ever thought to put a spoiler on a car. Maybe they were all proto-Jeremy Clarksons, “Power!” being the only thing worth pursuing. Who knows. This is a topic for another day, so let’s get back on track, back to wings and vents and diffusers and louvers and slats, oh my.

Once engineers began to aid gravity in sticking cars to the ground, they went wild with ways wind could be manipulated to produce podium finishes.  Group C cars like the infamous Le Mans-winning Porsche 962c and Mazda 787b were the posterchildren for the benefits of modern aerodynamics, but one must only glance at a Porsche 935 to see how we got there. Massive wings and cowcatcher front air-dams made the iconic 911 shape barely recognizable, but the most extreme piece of the 935’s aero package adorned not the body, but the wheels.

Dubbed, in totally consistent ’70s lingo, “turbofans,” these wheel attachments were the ultimate embodiment of form following function. Often painted up in garish but gorgeous contrasting colors, made of exotic magnesiums and kevlars, and sporting downright evil-looking knife-like air ducting, you knew that any car donning a set of ’fans meant business.

For racing applications, the idea was pretty simple: the channels beneath the outer cover would exert a centrifugal force on the hot air that stagnated around the brakes after heavy use, pulling this hot air away from the brakes, keeping them cooler and more effective. So that’s why they were invented, but their enduring legacy has little to do with maintaining optimal rotor temperature: it’s pure style. The kind of aesthetic impact that race cars have in spades. This is why the early ’fans that were not summarily tossed in the trash after races are so sought after today by wheel enthusiasts; no one in 2016 is driving on the street with these attached to their wheels so they can brake later into turns, it’s all about evoking the look and subsequent badassery of race cars.

It’s the same reason the last decade has seen flocks of street-shavingly low German cars, a style that originated to mimic absurdly dumped touring cars like the E30 M3s and 190e Evos that used to spark, rub, and no doubt level out the Nordschleife.

Turbofans are arguably just plain old awesome as material objects, but the real value comes from using their origins and current popularity to understand the relationship between race engineering and street car customization. BBS, the undisputed king of the turbofan, even went so far as to offer non-racing customers bolt-on covers for their RSes (as seen in the red-white colorway in the included advertisement).

BMW, in a flash of brilliance, even equipped the first-generation E34 M5s with honest-to-goodness turbofan wheels from the factory! Polarizing back then for being reminiscent of stodgy whitewall tires, it was a bold move, but one that highlighted just how pervasive and important turbofans used to be.

I think we should look back on this trend with the most rose-tinted glasses we can find; through turbofans we can see the endless pursuit of gaining an edge on competition (they represent an idea taken to the edge) as well as the dynamic relationship between function and form, between physics and style. Anyone who thinks they look like hubcaps just doesn’t get it.

Images provided by Alexander Sobran

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Nick BiangelJim LevittJavier BerrocalAdam DavidsonBrian E Recent comment authors
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Nick Biangel
Nick Biangel

I never knew the reason behind it. Very interesting.

Jim Levitt
Jim Levitt

I installed a set of BBS turbo fans on my 1985 911 Turbo look Targa. I had them painted body color. Only set around (on a street car).
Holbert Racing installed them on 15″ ultra wide wheels and tires

Javier Berrocal
Javier Berrocal

You can’t deny the fact that these are some of the best looking most recognizable wheels ever made.

Adam Davidson

I really never new what was going on with this style of wheel. I know it is supper 80’s (not accurate per yer), but did not know the purpose. I like them more now.

Brian E

Good article. The E34 M5 is second generation though.

Alexandre Zamariolli
Alexandre Zamariolli

May I say two words about the subject?
Thanks, here they go: Bugatti Royale.

GoLikeHellMachine
GoLikeHellMachine

The Porsche 935 debuted in 1976 according to Wikipedia, but I think the Shadow team in the Can Am series used a similar technology as early as 1970. They bolted centrifugal fans from air-cooled Chevrolet Corvair engines to their front wheels to draw cooling air over the brakes. I’ll admit it wasn’t as attractive as the Porsche version, but it was very much the same idea.

BDA
BDA

I’m surprised the author didn’t mention the attempts Ford made in their GT40 program. My understanding is they had huge brake problems – partially because the car was so heavy – and they tried to cool the brakes with “fan blades” cast (I assume they weren’t forged) into the wheels. I also understand that they were not successful in cooling the brakes so they were abandoned.

Obviously, it’s been figured out since then, but that’s the earliest reference to this sort of thing I’m aware of.

paul Bzzzz
paul Bzzzz

I can 2nd this as my neighbor worked on the GT40 program and told me how they’d attach cut telephone poles to a spool of cable and drop that from the roof to test the braking systems. They’d get them nuclear hot to test fanning cast inside the disks and inside different wheel configurations to get the heat out. First they’d warm the discs with a blow torch. I wish I had access to the pix he shared, it would be a fun post with their mid 60’s styling, all on a roof, freezing, dropping phone poles off. The people… Read more »

Wes Flack
Wes Flack

the coolest look is most always racecar

Peter Lukáč
Peter Lukáč

Oohh, my favourites!

Nicolas Moss
Nicolas Moss

Nice little article! I look forward to more essays about esoteric items that show up on our cars from time to time. As pointed out, we often do things to our rides because it enhances the fantasy we all harbor (sometimes secretly, sometimes overtly) that the trip to the grocery store is really just special stage in disguise. Now, if someone could just explain the phenomenon of the stretch & poke stance…

HitTheApex
HitTheApex

My explanation is imperfect, but my understanding is that stretch and poke comes from a western reinterpretation of the Japanese zokusha, as various regions’ tuning styles feature hippari (stretched) tires. As for the origin of hippari tires, one might find information by searching JapaneseNostalgicCar.com or BosozokuStyle.com.

Some people fit them because they want the aggressive look of wide wheels but are too cheap and/or style-oriented to pony up the cash for sufficiently wide performance tires to match the alloys, although in time this has become a trend all its own.

paul Bzzzz
paul Bzzzz

In Phoenix, a trip to the grocery store IS a special stage.