ghoffman

These are the first set of AP's Radi-Cal calipers in the USA that are presently being used in the DTM (German Touring Car) Series. They weigh 6.4 pounds each, have 25mm thick pads and have an air bridge that goes over the top of the caliper and cools the outside face of the rotor and caliper. I will post more later when they are mounted on my car. The red caliper shown is the big (8 pounds) Brembo. A version of this was used by Tony Stewart to win at the Glen.
Benefits:

AP Radi-Cal vs. Brembo and other 6 pot calipers:

1. Radi-Cal Design

a. Arrangement of caliper mounting points much closer to rotor centerline = massive stiffness increase

b. Smaller, more square box where pads reside = less deformation under load than a long pad box

c. Integrated diagonal support bridge

d. Offset caliper body design decreases deflection

e. Material removed around piston bores to increase cooling and lower weight

f. Article on design concept: http://www.autofieldguide.com/columns/1207euro.html

2. Provision for integrated carbon fiber air bridge

a. Increases airflow to outboard rotor face, caliper body, fluid, and pads, dramatically reducing total system temperatures

3. Forged monobloc vs. cast monobloc (Brembo) & two-piece squeeze-forged (StopTech)

a. AP is Stiffer/stronger

b. AP is Lighter- 6.4lbs. vs. roughly 8lbs.

4. Internal crossover ports

a. Less places for caliper to leak

b. Less chance of corrosion

c. Less weight

d. Less chance of damage during wheel install

5. No dust boots, only internal seals

a. They just burn up anyway on the track

6. Raw anodized with machined logo vs. painted caliper with silkscreen logo

a. Very little color shift- calipers look good even after heat and abuse

b. All parts look same, no uneven paint, chipping, flaking, shrinkage, or problems with brake fluid

c. Logo won’t smear, fall off, or yellow

7. Pad is roughly 25mm thick, vs. 14-17mm thick

a. Far superior pad wear, less pad changes, more heat capacity in pads because of greater pad volume

8. Stainless Steel Pistons

a. Much less heat transfer to caliper and brake fluid than aluminum pistons

9. Anti-knockback springs standard

a. Knockback big problem with uprights. More confidence when pedal is there= faster lap times…pedal is there when you need it, every time.

10. Stainless steel abutment plates

a. Brembo has none- pad will eventually wear away caliper body, “knock” around in caliper

11. Racing/Testing

a. These are exact same parts used in DTM, and very similar to those in NASCAR, F3, etc.

BrianCunningham

I'm going to need to lock my checkbook in a safe and give someone else they key

wallyman424

oh my... thats quite a caliper.

Cobra4B

Wow... that looks fancy

Jason

I'm going to need a moment.

ghoffman

And I just coincidently happened to have the Corvette adapters made already (this is not a Solidworks drawing).

wallyman424

so whats the damage on a set of these bad boys?

DarkMastyr

Rob Willis

They look HUGE, and I'm guessing will require a largely offset wheel?!

AverageVetteNut

Thank the gods that I'm poor

that way I don't have to imagine how cool those would be and what it would feel like to get my eyeballs sucked out by braking force.

thehammer69

For comparison sake, what is the weight of the OEM PBR calipers on the C5?

AU N EGL

Test driver ?

Falcon

Do those come with tissue?

ghoffman

The C6Z calipers are 9 pounds without pads, I don't know about the C5 caliper and steel bracket.
Here is it on a C6Z with CCW wheels. It has lots of clearance with the CCW's but a 1/4 inch spacer would be needed with the stock wheels.

wallyman424

actually the over caliper air bridge can be used as a vacuum to clean up afterwards. no mess.

wmckeenster

can we see pics of the pad comparison?

How much do they cost?

ghoffman

The pad shape is a 7778 and is available in from many companies. I am waiting on a set of 25mm thick PFC 05 compound pads. I will use others later but since I have been using the PFC 05 up to now I wanted to do an apples to apples comparison. I really do not know the price yet, it is still a TBD.

drivinhard

boy they machined all the weight they could out of those things.

25mm thick pad, wow, that' ~1" of pad material.

what size rotors are those brackets designed for?

ghoffman

Those are for 14 inch but it is a no brainer to use it with a spacer and longer SS shoulder bolts for 15 inch as well. That is not the production bracket, but is very close to it (a few thou here and there) but will be used for testing.

Everett Ogilvie

These are awesome Gary! Nice adaptor too!