Test Results are in:
Awesome, but noisy
Conditions: ran 199.9 miles at Lime Rock today with PCA-CVR, 6/25/20 70-85F, dry. (7) 25 minute sessions.
What: StopTech Level 2 Front Kit (STR43 calipers with 282mm x 28mm floating rotors) & ATE "M" (stock) rear, with Hawk HT-10 Pads, Castrol SRF fluid (fresh)
The Good:
1) ]They did not fade. The balance front to rear was fantastic, and best of all it did not change over the course of the day/session. The Braking on lap one (after the pads are properly bedded in) was just as good on lap 25. This is in contrast to the previous experiences where the front start to get a little mushy and the bias shifts the rear, resulting in rear lock up.
2) they really handle the heat better than 24mm wide Carrera Rotors and Wide-A calipers. I was able to increase braking force, for a shorter time (higher heat flux) without any issues. I was able to move my braking point about 50' closer to Big Bend. Lap after lap. Session after session.
3) After sitting for 30-45 minutes, it only took one pump on the brake pedal to bring back a firm pedal. Cooling and "shrinking" of the brake fluid is a common issue, but the amount of shrinkage is dependent upon how hot the fluid got. Must has been less than with the Wide-A pad size I ran two weeks ago. Brakes were firm and grippy immediately.
4) Pad wear seems to be very low. About 2 mm of wear in ~200 miles. This would normally be two days worth. With 20mm thick pads, they should be good for another 4 or more normal 100+ mile days
5) I never had any judder.
6) no overflow of brake fluid. Previously this happened all the time. Every track day. I would get a little puddle of brake fluid from the overflow. Not today.
7) fantastic, straight (w/open differential), controllable deceleration. Awesome.
The slightly Annoying: Light pedal pressure squeal from the HT-10s
1) This may be a trait of the the Hawk HT-10 pads. They do not come with anti-sqeal shims. They squealed loudly under light load after the heated up. Lap 2 till the end. This also happens with HT-10 pads on the stock rotors, but not to this extent. Only with light pressure. Like when you are trailing the brakes into a turn, just as you feather the brakes and go to the gas.
2) I really don't care that they are noisy. Maybe different pad compound would have less/no noise.
3) there is some heat checking on the rotors. Not really surprising considering how hard I was using them. This is more of an observation, as heat checking is common.
Some important points:
1) I broke the HT-10 pads in on the track. I ran the first 4 laps and got some smell. Pulled into the pits and sat for 5 minutes to let them cool. Then went out again for several more laps got some smell. Serendipity; we got black flagged for oil on the track, and that allowed the brakes to really cool down. The extra cool down probably helped as I never had "green fade".
2) I ran all cool down laps with virtually no brakes. And when I did stop I used the hand brake. I avoided pad transfer. by moving the car a little after about 1 minutes in the pits.
Side Note:
I really like Pagid RSL-29 Yellow Pads. They do not offer that compound in the 2205 pad shape. The HT-10 were a stop-gap move. Now that I have the StopTech DR-21 (2205) pads in hand, I am looking at the 2555 shape which is 45mm tall verses 43mm (2205) in RSL-29 compound. Time will tell if the extra 2mm really impact the installation.
Link to Install