Did you say active brake flaps? Here's some inspiration for you... http://www.youtube.com/watch?feature...GHY_Al_I#t=361

 

I do a lot of work in thermal dynamics by trade. I know a little bit about aero. The wing I am using is an airfoil and I do in fact see in increase in down force as well as stability since the addition of this system. There is no doubting its functionality.

 

Very cool! I have never seen that before. Thanks.

 

Whether the label on the car says Porsche or Yugo, the laws of physics are the same: the limiting factor is tire grip, even with a Hoosier race tire. As I said above, there are other factors that come into play, like heat dissipation, but putting larger rotors and better compound on a car will not be more effective in reducing brake distance.

I am a long time PCA member and trackster. I have witnessed the affinity that PCA track rats have for big brakes and wings. More often than not, these add-ons don't improve the performance of the cars on the track: they improve the performance of the cars in the paddock, if you get my meaning.

 

Better brakes brings you to the tires' limit faster, don't they?

I would encourage the OP to test his wing as it's shown to operate in the video. Take it on the track at various speeds and record its effectiveness, in straight line stops and around the track.

You're correct about fancy sports car owners. The accessories are there for them to jerk off on, not necessarily to use effectively.

 

Those are too slow. This is the Mercedes you want...

 

In my case I have a lot of tire (225/35/17), a lot of brakes (13" x 1.25" rotors + 4 piston calipers), and now Aero. Before the car was squirrely under heavy braking. Now it is not. Before the rear would give an uneasy rotation under hard cornering. Now it does not. For me ;whom owns the car and built the system, it works. I am VERY happy with the handling and braking performance of the Beest.

Now if I can only get these ARP head studs to stay torqued. I have a new head gasket on the way. I am going to have to heat cycle the engine and then re-torque the stud nuts. I guess 24psi of boost will do that.

 

That, I have seen

 

As you described, it works as a spoiler to increase down force and improves stability of the rear end. That I wouldn't doubt. But as an "airbrake", have you tried having it stand up to see if it decreases the stopping distance?

 

Are you seriously going to argue with me about this? The very fact that it creates additional downforce on the rear of the car, further increases the effectiveness of the rear brakes, reduces nose dive, and reduces the load on the front brakes. The slower increasing angle of attack while braking keeps the force linear vs. disruptive. I am happy with the results.

I'll run some measured test when I get a chance, but keep in mind I really don't have any intentions on selling this.

 

It's a logical idea, but there's more to it. Here is what you need to consider:

Remember what your original theory was: that larger rotors and better pad compound stop cars faster than a car with stock sized brakes combined with an air brake.

-If you just put a big brake kit onto a car, it almost certainly has different-from-factory brake cylinder volume. By changing the cylinder-to-master ratio, you're changing the brake bias of the car, upsetting the balance of the car at its braking limit, and potentially decreasing brake performance.

-If the increased pad-to-rotor friction of a bolt-on big brake kit brings the car to the braking limit (read: lockup) faster, you are likely to increase stopping distance, since you will be locking your wheels sooner than you would with a factory-engineered system.

There are some factors that would support your theory in a slightly different situation. If you are talking about track use, and not a street car (The Wildebeest is primarily a street car, with occasional track use), the greater thermal mass and surface area of a big brake kit would better handle the extreme heat generated at the track. Many good production based race cars have fully engineered big brake kits, with adjustable bias and supplemental cooling. These should not be confused with a bolt-on BBK that you see at your local driver's event.

The bottom line: the above circumstances notwithstanding, as a general rule, the limiting factor in mechanical (non aero) braking performance is tire adhesion.

 

Thanks for ^^^.

 

1. Aren't we saying the same thing here with me calling it a spoiler (if the angles wasn't perpendicular or thereabout to the pavement) and you calling it air brake? I have driven the following cars either here in the US or Germany at sustained speeds of ~120mph. I have an idea of how this component improves stability. When driving from Berlin to Munich on wet pavement at 180-210kph, you learn appreciate downforce... or a cabin full of passengers and luggage.

Would you then say that the following cars have air brakes?

VW added this spoiler to the last generation New Beetle 1.8T after some complaints by journalists that the car was slightly unstable at Autobahn speeds, especially with cross-winds. VW-programed ECU raises spoiler at 87mph. US customers whined about it so VW changed the activation speed to 45mph for the US version.

RSI New Beetle (available only in Europe, street version of their Club Racing NB Cup Car). Notice the boxed diverter (1:45-1:53) on top of the rear windshield to aid airflow onto the spoiler. 3.2 VR6, AWD, lots of grip.

factory spoiler on a 944 series, with lower diffuser on the Turbo / Turbo S variants...


They all improve rear stability by increasing downforce... thus traction... AND braking.

OTOH, no spoiler but lots of adrenaline. The Suzuki Sidekick (or literally side-kicked) gets pushed about 1/4 to 1/2 lane to the right when a sizable car like a Merc S Klasse or land yacht passes it at 2x the speed on the left lane. Anticipating traffic coming from behind and steering correction was quite interesting...



2. Looking forward to your findings. Your results may encourage me to build a bracket on which I can strap my surf/boogie board... multi-purpose. Down to the beach with downforce, baby! Have a nice weekend.