GT brake ducts

[ChipBeck]

Brake dance at LeMans.

One other question... on the older GTs (GT40s) Shelby did not want the brakes cooled this way. He thought that it would cause problems at Le Mans. The Ford team did duct cold air to the brakes and the front rotors warped on them. Shelby's team did not and their brakes performed better as the race wore on. Any thoughts?

Fubar,

The Shelby prepared GT40s did duct air to their brakes at LeMans. But for this particular race they used air taken from just behind the radiator which was warmer of course then the ambient temperature air picked up by the standard front mounted brake ducts on the Holman-Moody prepared GT40s. That was back in the days when the two-mile long Mulsanne straight had no S turns in it to slow the cars. That long two-mile stretch without any breaking had so much cold air blasting onto the brakes for such a long period of time that it caused a huge and rapid reduction in brake rotor temperature which led to the warping. But Shelby knew that the GT40 brakes needed some cooling in order to survive for any reasonable length of time. Pulling warmer air from behind the radiator was their compromise solution that kept the front rotors from cooling too much at the end of that long straight. In all other races that I am aware of Shelby switched back to the front mounted brake ducts as they were more effective.

If Team Shelby was racing at LeMans as it exists today, with the Mulsanne straight effectively broken into three sections, I am reasonably certain they would use the standard front mounted brake ducts. All the best.

Chip

 

[Fubar]

Wow... great information, thanks Chip.

 

[MAD IN NC]

Chip to the rescue! :thumbsup

 

[roketman]

"The modification to open up your front brake scoops to be function will not effect the lift/downforce of the vehicle so you are good there. It will effect the drag number, it raises it 10 counts, which is about 2.5%. I wouldn't worry about it because your vehicle, with no power mods, could exceed your clipped top speed of 205 mph by 3.4%. So you will still be able to go 205.

FYI
The open ducts do help the brake cooling quite a bit. The reason that we did not open them up is actually a long story, but the short version is that they added some drag and we engineered the braking system to not need them. Now if you change pad material to a more aggressive compound or increase the front tire width or increase the front tire stick you will overtemp the brakes at a track event and need to open up the ducts."
An email I got from Tom Reichenbach

 

[dbackg]

Well we thought we would share another one of our track packages. We have done this to a few other cars as well. While the install isn't for the faint of heart but the functionality is worth it. The a/c line has to be reworked on the passenger side to clear the ducting. We clamp the tubing to the back of the ducts on the fascia and then run the tubing next to the cooling module and then to our bulkhead connector in the inner splash shield. Then another piece of tubing going from the splash shield connector to a fitting that bolts to the knuckle. This way the hose has a solid connection at both ends. Also this hose can be replaced without removing the front fascia. And just in case you are curious the tire doesn't contact the hose as we did the study with the shock off and moved the wheel through the entire travel and lock to lock.
We have also done some cooling module work to help out for the track. Stay tuned for pics in that in another thead. Also stay tuned for another package that is in developement now.

Also notice the new T&A Shocks single adjustable shocks.

The functional front brake ducts are amazing.

What's the new development package? Staying tuned.

 

[Indy GT]

"The modification to open up your front brake scoops to be function will not effect the lift/downforce of the vehicle so you are good there. It will effect the drag number, it raises it 10 counts, which is about 2.5%. I wouldn't worry about it because your vehicle, with no power mods, could exceed your clipped top speed of 205 mph by 3.4%. So you will still be able to go 205."

An email I got from Tom Reichenbach

Thanks Tom for setting the record straight with internal engineering facts. This topic has been bantered about for years as most just did not understand how opening up these ducts can increase drag. But it obviously does as I have stated in many posts.

For unmoded FGT's no big deal as the increased drag is more than compensated by the excess engine power available at our ECU clipped speed of 205. But modded engines (pulley's, Whipple's and TT's) the increased drag WILL effect your top speed.

 

[Ed Sims]

drag vs brake cooling

Why not have the functioning brake ducts for the track events & then cover up the duct openings for speed events? That's my plan.

Ed

 

[dbackg]

Why not have the functioning brake ducts for the track events & then cover up the duct openings for speed events? That's my plan.

Ed

Yes! Elementary, my dear Watson ... Sims. Brilliant.

So simple yet we make it so complex.

Ed. Please keep us posted. I would love that setup.

 

[roketman]

I just tape over them for speed events

 

[dbackg]

I just tape over them for speed events

Tape.

I don't have time to do that when the police are chasing. :driving:

Words of wisdom.

1. It wasn't me.
2. Deny. Deny. Deny
3. Prove it.

All said in jest, of course. :wink

Happy Thanksgiving to all.