AP Radi-Cal

[jacobe92]

Post plenty of still pictures here once installed. 👌

[jacobe92]

https://www.facebook.com/EssexPartsD...5541501598897/

[EGbeater]

Originally Posted by jacobe92

I've been able to late brake more than ever into a turn.

So, you went from a 380mm Brembo GT kit to the 372mm Essex/AP 9668 Radi-CAL Pro5000R, and overall, the braking power has improved?

What about heat capacity of the Essex brakes/J-hook slotted rotors during extended hot lapping vs the Brembos, assuming nothing else has changed (e.g., no ducting or scoops added)?

Thank you very much for your information.

[jacobe92]

Originally Posted by EGbeater

So, you went from a 380mm Brembo GT kit to the 372mm Essex/AP 9668 Radi-CAL Pro5000R, and overall, the braking power has improved?

What about heat capacity of the Essex brakes/J-hook slotted rotors during extended hot lapping vs the Brembos, assuming nothing else has changed (e.g., no ducting or scoops added)?

Thank you very much for your information.

Rotor size from 380mm to 372mm for heat capacity, IMO, is negligible. Also it helps that I'm running the DS11.1 "More for track" now as oppose to the Endless ME20. I wouldn't know much about extended track sessions. Here at SoCal our sessions average about 25 to 30 min and I don't find the need for ducting or scoops. On the flip side, maybe I'm just not pushing it hard enough. Maybe someone else can chime in?
P.S. I used to run rotor size front 365mm and rear 345mm. It gives you the most 18"wheel selection that can accommodate a BBK than any other rotor sizes. 380mm F/R are more for Bling than anything else, I would know. I wish the 9668 and 9449 have these sizes.

[Gomeler]

Originally Posted by jacobe92

Rotor size from 380mm to 372mm for heat capacity, IMO is negligee. It also helps that I'm running the DS11.1 "More for track" now as oppose to the Endless ME20. I wouldn't know much about extended track sessions. Here at SoCal our sessions average about 25 to 30 min and I don't find the need for ducting or scoops. On the flip side, maybe I'm just not pushing it hard enough. Maybe someone else can chime in.
P.S. I used to run rotor size front 365mm and rear 345mm. It gives you the most 18"wheel selection that can accommodate a BBK than any other rotor sizes. 380mm F/R are more for Bling than anything else, I would know. I wish the 9668 and 9449 have these sizes.

AP Racing has some marketing material on the composition of the rotor internals, and how important that was for rejecting heat. Several reports of people not having brake fade running the 9668s without ducts through extended sessions. That being said, heat is almost always the enemy, so long as you can at least keep the pads around their optimal temperature after really long straights. I bet the front hubs would love a little bit of cooling, even with the thermal isolation that the 2-piece rotor adds.

[bracer]

There is more that goes into this. Piston sizing, piston material (and how that material rejects heat), caliper flex, brake pads to name a few. Also the AP Racing Essex designs show above do not use dust shields. 1 track event on the Brembo or Stoptech will overheat and crack the dust shields.

Fronts help alot, the rears made a big difference as well with balance.

[EGbeater]

Originally Posted by jacobe92

Rotor size from 380mm to 372mm for heat capacity, IMO is negligee.

I would agree.

Originally Posted by jacobe92

I wouldn't know much about extended track sessions. Here at SoCal our sessions average about 25 to 30 min and I don't find the need for ducting or scoops. On the flip side, maybe I'm just not pushing it hard enough. Maybe someone else can chime in.

25-30 minutes definitely qualifies for what I'd call an "extended track session." On hot days in Colorado (high altitude = low air density = exacerbated cooling issues compared to you lucky gooses living at sea level), my C6 Z06 would overheat (250+ coolant temps) after about 4 or 5 consecutive hot laps (on a sub-2:00 course), so anything beyond 20 minutes of continuous hot lapping is an "extended track session" by my standards...

Originally Posted by Gomeler

heat is almost always the enemy, so long as you can at least keep the pads around their optimal temperature after really long straights. I bet the front hubs would love a little bit of cooling, even with the thermal isolation that the 2-piece rotor adds.

Again, agreed. If nothing else, adding brake cooling via directed air should extend pad and rotor life, even if the fluid doesn't boil or the pedal soften at all toward the end of hard session.