While considering whether to follow this route last night a thought occurred to me

Generally one ducts into the centre of the disc so that air can flow through the ventilated section.

The TRD disks i have fitted have a "scoop" effect on the outer edge fins. That is to say these fins are not perpendicular to the edge of the disc but rather are angled. It looks exactly like a waterwheel running in reverse

Thinking about this a little further, if the disc is trying to scoop air from the outer edge it must exit in the centre of the bell.
If I am trying to duct air in to the bell and the disk is trying to vent air from the bell do I run the risk of stalling airflow completely and inadvertantly causing less cooling?

Discuss

have you considered pointing the ducting at the caliper itself rather than the disc?

as you say, the discs are vented and so will try to look after themselves. in my limited experience, when brake fade occurs its down to the pads overheating in the caliper (witness my smoking pads at the haynes trackday) so whenever i have thought about fitting ducting its always been with the intention of cooling the caliper.

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Sprint ST165 aka "The 500BHP Sledgehammer" #6 in the Toyota Sprint Series. GT3071 1.9bar

Funny this should come up, I have been looking into this for a while now.
I got some pictures from my recent visit to beaulieu from the F1 cars & they seem to cool the rotors as does anything else I find on the net.
Did find a site that talked about water cooling the Cal's but I cant find the site on this work PC

Heres some links, I think the last one is the best.

http://www.ttzd.com/izcctech.html

http://zhome.com/ZCMnL/PICS/BrakeDucts/ducts.html

http://www.ctautoengineering.com/bdck.htm

http://www.timskelton.com/lightning/rac ... _ducts.htm

Depending on the type of rotors used, most draw air in from the centre 99.999999%r and expel the air form the out side edge.

Some have a built in fan blade running of the centre shaft, this increases slow speed air movement, so a constant airflow can be achieved great for heavy braking tracks, with lots of low speed bends

I have some pictures of the set-up, form a touring car.

The outer edge travels faster than the inside centre
Centrifugal forces etc, same rules applied as impeller laws.

The vanes on racing rotors are not straight fluted type

I have worked on many group A race /rally cars, venting from front via pipe work to the centre of the wheel bearing and bell.

Cooling helps stabilize both braking system and wheel bearings.

Sorry for quality, have better somewhere.

Image shown: front left, without the bell and rotor fitted.

You can see the aluminium shroud around the bearing hub connected to the upright, in side, it has a 4” stainless fan blade, and this is attached to the inner wheel bearing shaft, not front wheel drive.

Want to make something up like that for my car jon??

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ST205 WRC #0002249

Hi.

Will dig full set off pictures out, shows the fan, cowling, outer shroud etc?


Its no problem to make them.

They do make a big difference in keeping the wheel bearings cooler, people forget about the wheel bearings.

Hmmm,

Mebbe I've mis-interpreted the way the in disc vanes appear to work then

they are definitely at an angle like \
with the wheel spinning clockwise

I'd figured that this would effectivly scoop air in from the outside edge but I was wondering about the whole centrifuge thing too....

Steve - I wonder if this is also the reason why the stock 205 disks are handed?

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

Hi.
a few more of the rear and front brake duct and fan unit.






I hope this helps to clear up a few things.

A real must for the rear, as this thing would pump out more than 650 horses

the bells, rotors, calipers all AP racing, so nothing special there.

Steve, you ever thought that you might have the discs on the wrong side? Was down at the Jap fest and was amazed at how many people where running after market discs on the side. Like you say the air should travel from the inside out as the wheel rotate not scooped. Just a thought. Dorris

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Black CS 2771