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Brake Development for Corvette C8

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  • Brake Development for Corvette C8

    Corvette C8 Tech/Performance

    https://www.corvetteforum.com/forums...rformance-177/

    Rotor Size:
    FRONT Wt (lbs) REAR Wt (lbs)
    STANDARD 12.6 x 1.18 (321 x 30) 20.06 13.6 x 1.02 (339 x 26) 17.54
    Z51 13.3 x 1.18 (345 x 30) 24.12 13.8 x 1.06 (350 x 27) 22.40
    Front Caliper:

    Click image for larger versionName:	front-caliper.pngViews:	1Size:	120.3 KBID:	11665
    Rear Caliper:

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  • #2
    Brake pads offered by Carbotech:
    Carbotech C8 brake pads including LOW DUST for the Z51 avaliable now
    https://www.corvetteforum.com/forums...post1601604937

    2020 C8 Z51 part numbers.

    CT28951F CT28951R

    Front Rear

    1521 $284.00 1521 $214.00

    AX6 $295.00 AX6 $223.00

    XP8 $307.00 XP8 $231.00

    XP10 $319.00 XP10 $241.00

    XP12 $332.00 XP12 $250.00

    RP2 $342.00 RP2 $258.00

    XP20 $352.00 XP20 $266.00

    XP24 $374.00 XP24 $282.00

    Comment


    • #3
      —NEW PROJECT— GSpeed C8 Corvette

      https://www.corvetteforum.com/forums...post1601604937

      Pads: When I arrived early, Chase was wrapping up the brake pad swap. We had run out of factory pad and Cobalt had sent us several sets to test. We did this as a ‘pad slap’ and sent it. As we all know, there will be pad material left on the rotor and TYPICALLY Cobalt pads can be pad-slapped with zero issues. Of course….we had issues.

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      The Michelin warm up was a few laps to get everything warm and bed in the pads a bit but by the time I came in, a light braking application resulted in a good vibration. Pushing through this vibration reduced it a ton, but being a big trail-braker I was hoping this would work itself out soon. <Foreshadowing> <Would the brake vibration only cause one problem? No…no it would not> <sigh>

      We have a quick chat and decide to pull the Michelins and go to the Finspeed/Hoosier setup. A passenger slides in and off we scoot for two laps to get rid of the mold release and get some pressure built up. Back in the hot pits, the crew ensures nothing is rubbing, re-torques the brand new wheels and away we go. The brake vibration is inconsistent but still only really noticeable on light brake application. When I really get into the brakes the vibration is greatly reduced and the brakes feel great.

      So….you see this coming right?

      We go back out, and I warm the tires more and setup for a “pretty quick” lap. I go through rattlesnake (largest waste of track in Texas, I’ll fight you if you disagree) and head down the hill, making a nice two-apexer and scoot up the hill toward Ricochet. I’m carrying too much speed so I lift and ease into the brakes to bleed off some MPHs and the vibration is very faint. I get to the turn in point and my left foot is barely breathing on the brakes and as I rotate the car in, the car USUALLY slows down a bit more. The big heavy Michelins and the big heavy factory wheels get impacted by the slip angle the Michelins operate at and we slide a bit and that slide creates friction and allows me to lose that last 1-2 mph so my apex speed is perfect.

      Usually. However, the Hoosiers operate at a much lower slip angle. Especially when I’m not asking for full grip, I’m just asking for a twitch. The Finspeeds are light and stiff and are not impacted and so my speed stays up. No big deal, I’ll just give it JUST A BIT MORE BRAKE PEDAL on my way to the apex. Easy peasy.

      It was, in fact, not easy peasy. The vibration got a bit worse, the back end started to step out and I’m quickly presented with two options. A) Try and catch it and slide it down, then correct and go. If this works I’m a hero, and if the rear bites in, I’ll experience snap oversteer the other way and we’ll go backwards off the track at 80 mph. Consequence of action: Low chance of success, high chance of Louis not happy. Or, we can do B) Straighten up, slow down as much as I can, go straight off in a controlled fashion, drive AROUND the pothole at the end of the rumbles and come back on track. Consequence of action: I end up taking Slick off road, but it’s dry and low chance of not happy Louis.

      Option B it is and you can hear my passenger laughing as we go off.

      Pulled back into the pits. Chase: “that grass was way too long over there, good job”. I love my crew.

      With that we get the Hoosier’s up to speed and while the brakes are beginning to cohabitate better, they’re not the usual Cobalt-perfect, but honestly it is not their fault. We should have pulled the rotors and did a light cut on them or put on fresh rotors. I’ve worked hard and spend a ton of time/money/testing to find out what allows me to pad slap from street to track pads with no cutting, but that’s a story for another time.

      After a few sessions we get everything we can out of the Hoosiers. It is lunchtime and we sit and do a deeper debrief. The car is not balanced. It is kinda close, but we’ve got a low speed push (not horrible) and we’ve got high speed oversteer. We are losing exit speed in ricochet, complex and big bend due to the high speed push. At medium speed and high speed we have great turn-in. At low speed the oversteer is manageable. (reminder: I’m in track mode with all nannies off. We’ve tested the race modes and PTM stuff…I prefer it all off. On the fastest mode one time I was exiting Big Bend at the turning limit over 100mph and some nannie played with the brakes and I almost went agricultural. Not cool.)
      Attached Files

      Comment


      • #4
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        Comment


        • #5
          2pc rotors offer by Girodisc $1,900 for a car set (4 rotors):
          Rotor weight:
          Front 21 lbs
          Rear 17.5 lbs

          Comment


          • #6
            Test fit of 420x40 Carbon Ceramic Brake Kit with RB 6XL calipers for Corvette C8 front.

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            Side View

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            Attached Files

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