Owner Impressions: Essex Designed AP Racing Radi-Cal Brakes for the 981 Cayman GT4

In an effort to continuously provide the cutting-edge products our customers want and need, Essex sponsors nearly a dozen automotive enthusiast message forums. We recently stumbled upon an owner's initial impressions of our AP Racing by Essex Radi-CAL Competition Brake Kit. The post on Rennlist also received several additional positive comments from other enthusiastic owners!

"The calipers are a masterpiece. The engineering and function of the part is second to none. I have no worry about quick/easy pad changes and broken ceramic pucks anymore. That, for me, was worth the price of admission.

The rotors are also a masterpiece in their design (ability to expand outwards when hot, due to the free floating design). The ability to expand and avoid "curling" of the rotor was what sold me. I'm a concrete guy, and curling of a slab is a phenomenon that occurs with all slabs and causes a serious structural issue - anything to avoid this is a great thing. So, I could relate when I saw the image of the Essex website that spoke about rotors doing the same thing when they get hot, expand, and are restrained thus the "curl."

I decided to go with the DS2500 pads. They make no noise on the street. They feel good, but not great. The initial bite is vague, but the modulation is good. For the street, they will suite my needs just fine. But for the track, I'll swap out to something with more initial bite and better pedal feel.

The brake lines are a pain, and you should take your time and read the instructions twice. Again, take your time when clocking the brake lines. We found out the hard way that if you don't clock the rear lines just right you will cause a rub with the rear tire and it will wear through the black shielding. We quickly re-clocked the line to fit tight against the chassis so all seems to be good now. (*editor note: All brake lines are a pain on these cars!)

We used a pressure bleeder for the first half bottle of SRF until we removed most of the air. Then, we switched to the good ole fashioned manual bleed with me on the brake pedal and a buddy on the bleed screw. We extracted a great deal of air that way, and made at least (3) rotations around the car and went through nearly 2 full bottles of SRF just for good measure - I'm a stickler about feeling good when it comes to brakes, and knowing that we took every measure to ensure the best outcome.

I would recommend going with the caliper bridge ("spring clips" so I call them) that hold the pads in nice and tight. This prevents any pad shift/clicking noise on the street.

And, spend the money and have Essex bed the rotors for you! It's very accurate, the kit is ready to go out of the box, and you don't take unnecessary risk on the street!"

Front

Below is what our pre-bedded discs look like out of the box...ready for action!

Rear

Essex Designed AP Racing Radi-CAL Competition Brake Kit (Front 9661/394mm)- Porsche 981 GT4

Essex Designed AP Racing Radi-CAL Competition Brake Kit (Rear 9449/380mm)- Porsche 981 GT4