Brake cooling

D

danshonda12

Member
Hoping someone can give me info on these bbs looking brake cooling wheel covers? I have been told you have to make these from scratch? Or does someone make these? I do not know much about them so was just curious if thats what these are, and where to get some. Thanks in advance for any info. I am coming over to closed wheel from open wheel, so still getting adapted.

Dan
 
danshonda12 said:
Hoping someone can give me info on these bbs looking brake cooling wheel covers? I have been told you have to make these from scratch? Or does someone make these? I do not know much about them so was just curious if thats what these are, and where to get some. Thanks in advance for any info. I am coming over to closed wheel from open wheel, so still getting adapted.

Dan
Click to expand...

They are BBS wheel fans. I've seen these on a number of Porsche cars over the years. I don't know if they still make them.
 
In the 80's, they were used on Trans-AM, IMSA GTO and Prototype cars. These cars had too much HP, high top speed and brake discs that could be used for bistro tables at a French Cafe. Were most frequently used on street courses and tracks that placed a high demand on braking. Some considered them an aero advantage at Daytona, because they made the outer surface of the wheel smoother, reducing outer turbulance. The fans were mounted to the center flange of the wheel, using rivets, sheet metal screws or studs. You needed to be aware of wheel balance and centering the units when mounting them. They were easily used with a single center nut used for attaching the wheel. But, were a little awkward when using 5 lug nuts to secure the wheel. They were easily damaged or destroyed as a result of minor contact on the track. The wheel fans were made of plastic and would easily shatter. I sold a set of these last year. Expect to pay $200+ for a set.

They are probably overkill for a Prod car. You would be better served with good brake ducting, with ducting fitted closely into the brake center and using a high quality racing brake fluid. If you need these wheel fans on a Prod car, A) you have other problems that need to be addressed first or B) you are overusing your brakes and would probably be better served by simply removing the brake pedal.

Some FWD VW drivers may disagree, since they are rules limited to using a too small brake disc/hub setup.

Porsche drivers use them because the Father Land told them to. MG drivers use them because they looked good on the Porsche that passed them.

The fans can be easily fabricated using some aluminum sheet. Cut a round outer piece to fit the ID of your wheels, make some angle brackets for the blades, make a center tube and make 2 flanges. Mount the center tube to a flange for mounting to the face of the wheel. And mount the outer face to a flange connecting to the center tube. When they are damaged on the track from minor contact, the aluminum may cut your tire. You might consider using a plastic instead.

Use the pictures as a pattern, using the attached link:
http://s1192.photobucket.com/albums/aa339/JOHNMCNAUGHTON/SOLD%20-%20BBS%20WHEEL%20FANS/
 
Mike,

As a former brake design engineer for Ford, Bendix, Kelsey Hayes I can assure you properly designed brake fans make a big difference. I fabricated a set for my HP sprite and ran them for years. I ran a back to back test at the June Sprints around 1995 wher the fans were worth 150F rotor temp reduction. Just imagine what they would do at a track like Blackhawk Farms!!

If you call I can give you details on how to fabricate them, make them fit and work, even with complex profile wheels like miniltes. w: 317-733 9644 x18

They are definately NOT overkill for a production car. I was the racer who requested and received the rule change to allow them. Not sure, just ask anyone who has had brake fade. Not sure if that what bit Eric Prill at the Runoffs or not but if so.........these would have placed him on the top step.

There are many other brake related tricks I can share as well.
 
During 2002 Erik Skirmants used them on the E prod Miata Boigmobile along with very well designed brake ducts. You could call Erik at SCCA Enterprises inc.

Here are a couple different concepts. :think:

http://ultracoolbrakefans.com/main/

On these pictures look at pictures #93 forward for construction. Replace molded stuff with aluminum or ???.

http://www.mat.fi/n_index.php?nav=gallery_view&gallery=project1990lanciadeltaexbiasion&g=13
 
Jay Lutz said:
They are definately NOT overkill for a production car. I was the racer who requested and received the rule change to allow them. Not sure, just ask anyone who has had brake fade. Not sure if that what bit Eric Prill at the Runoffs or not but if so.........these would have placed him on the top step.
Click to expand...

Eric was running cooling fans most of the year but I think a mounting stud broke while at RA or right before and he did not have them on the car for the Runoffs.
 
Okay ... I'll bite ....

If you have measured brake temperature issues and you've run out of ducting options, I can see these being something worth looking into.

In GT we're allowed any brakes we want (iron rotors), and I've never seen a GTL car (most comparable GT class to prod) run out of brakes.

In fact, after spending time measuring brake temps with paint, IR, etc; I've determined that my brakes are over cooled. Mine are 10.25" vented rotors with superlite sized calipers. This was backed up by PFC engineers at the runoffs in 2011 (RA is the hardest track on brakes I have run).

Modern pad materials (i.e., PFC 01, 03, 07, etc) are so tolerant of high temps (in fact they require them), that brake cooling needs far less than they were in the past.

If you were REALLY tricky and wanted to undertake the engineering exercise of seeing how you could minimize MOI and unsprung weight by running the smallest brakes possible while using all the cooling trick possible (ducts, fans, electric fans, etc), you might see gains.

I almost never hear folks saying that they're running out of brakes. Even some of the heavy EP cars don't seem to have issues. So why is extra cooling beneficial, especially cooling that has pumping loses (costs horsepower)?

Bottom line: IMHO buy some temperature indicating paint for the rotors and thermax stickers for the calipers and measure your rotor and caliper temps before you go installing do-dads that cost you horsepower.

-Kyle

PS: One aspect of these that might also be worth looking into is their ability to evacuate air from under the nose of the car. It raises some questions about their legality as "moving aerodynamic devices". I'll have to consult the GCR to see if there is actually a rule forbidding that in Prod. But hey ... it is the silly season afterall.

PPS: Les' 914 is one of my all time favorite prod cars. It's one of, if not the best turned out race cars in our grid. I didn't want to come off as knocking Les or his cars. Both are excellent examples of the club racing ideal.
 
Kyle,

That's EXACTLY what Lotus does on their current street cars. Look at the diameter, thickness plus no vented rotors of most Lotus street cars and you will initially say to yourself........how long before these brakes fade????..........then you think.

But wait....but there is so little kinetic energy!!! KE=1/2MV^2. Mass is super low and more importantly top speed is generally low keeping V^2 super low. If KE requirements are low you don't need a lot of thermal mass to shed the relatively little bit of heat generated.

Lotus does this on purpose since big heavy robust brakes have to spin up and down to speed and of course have to be accelerated as part of the vehicle mass. Low MOI, low spinning mass, low vehicle mass is good here.
 
Great info guys! Thanks. I have a First Gen Honda Civic that I am re-building for GTL. Jay, would you consider making a set if I decide to go that route? I am more on the side of looking good, and I have run out of brakes in a formula car, and it was not a good feeling, lol. Just looking around right now I guess to see if anyone would be interested in making a set for me if I decide to use them. Thanks everyone!

Dan
 
Dan,

Old School was to use an magnesium Corvair fan.

Jay,

Any fan moving any air has to derive that energy from somewhere, right? Nothing's free. For underpowered Prod and GTL cars I had always assumed, perhaps incorrectly, that a fan could never be worth the power to run it? When does it make sense in your opinion?
 
Curtis,

Your thoughts on the power to drive the fan may be correct.....but what do you lose by not having ABSOLUTE confidence that your brake pedal will be there when you need it??. I tested them mounted to a 13" minilite wheel on a lathe and the pumping action was decent but not as good as the video above which has far more aggressive vanes than mine.

Dan,

I spent 40 hrs making 4 for my H car....so this project is not for the feint of heart.....sorry, no interest on my end.

If you could just adapt something pretty close ie a fan of some sort and just make a hub you would have it licked. BTW, be sure the fan attaches to the wheel and not the lug nuts. If it attaches to the lug nuts some genius SCCA tech guy will call it a wheel cover which are NOT allowed. Trust me on this......I've been through it.
 
Just for fun I'll see if I still have a pic of mine..........you'll understand why they took so long to make when you see them.
 
Jay, here's a beer. Pull up a chair and I will quietly listen to you all day. Thanks for the information you bring to the conversation.

I once had massive brake fade, very early in my SCCA career. Driving my hot little Lotus, nearing the end of a long straight, I gently tapped my brake pedal. And, it gently tapped me back when it bounced off the floor!!! Never take your autocross car with autocross brake pads to a brake heavy, temporary, airport road course.... It will take your breath away. I had a panoramic 360* view of that turn.

I have never run the mid west courses. Apparently some of them are brake intensive with 13" wheels and discs. My experience is with several GT1 cars and RX7 E/P, TransAm & GTO cars, with more than adequate ventilated brakes.
 
I looked.........sorry no brake fan pics. Maybe the racer that bought them could post the pic? I have no recollection who that was other than he was one smart guy buying them so cheaply.
 
Thanks John, it helps to have practical experience in a subject area....not just book learnin from enjineer schoolin! Like most people on the forum I know a little about many subjects, just enough to be dangerous. I fill in the gaps with common sense and the occasional line of BS. Luckily I rarely get caught with my pants down.
 
Dan,

Peter Zekert had some on his car at the runoffs this year. Call him. I'm sure he'd be happy to help.

-Kyle
 
Dan, use your friend Google. I found a pair (2) that sold for, sit down, $1000.00. :roll:

You might check with wheel manufactures, I read some stuff that they do magic with their spooks towards air flow past the calipers/rotors. :think:
 
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