I've got manual brakes, a Wilwood 7/8" bore master cylinder to be precise.
Todd, I'm a bit surprised they just use silicone too. I guess for them it is the best solution for a street car. Since they race what they sell, and they predominantly sell to people who will almost never drive on the track, their setup makes sense. There would be no point in running a full floater on their cars and then selling the Torino Bearing 9" setup to the public. I do wish they sold a setup that was overkill though, I know I would buy it.
As for what knock back is, I think Greg might have posted a good link explaining it somewhere. Basically, under hard side loading, going around turns, there is enough stress on the bearings, and axle components that everything moves a bit causing deflection. What this does to the rotors could be compared to an outside wheel on an old car gaining positive camber around a turn. In other words the rotor flexes and is no longer perfectly parallel to the brake caliper, thus pushing the pads and pistons back. Then, when you need to brake and you step on the pedal, you get a really light feeling i.e. the pedal might fall halfway to the floor, or feel like it isn't bled properly. If you tap the brakes once and push the pistons back in place everything will feel normal again. I think, and correct me if I'm wrong, power boosters, like what DSE runs, will cut down on the amount of noticeable knock back feel, but doesn't address or cure the problem. On manual brakes like a bunch of us are running it is very noticeable. I've got a 7/8" Wilwood manual setup, and it does not inspire confidence before you tap the brakes up.
Here is a picture of one of our car's rear rotors. I think the reason I never noticed bad knockback sooner was because the rear calipers weren't evenly spaced and whenever I'd go around a hard turn, the rotors would grind against the retaining pins between the padlets on the C6 Z06 brakes. Because of this knockback was limited, and less apparent. The downside though, was that my rear brakes weren't ever working 100 percent.
You can see the ring caused by the deflection, where the rotors ground against the retaining pins:
Matt
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
I can't believe DSE silicones in their axles between events. No way I would put up with that crap! Matt, what master cyinder and is there any booster or hydraboost?
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