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I read in a few different areas the rear base actually had the larger piston by 2mm. Recall this pretty clearly as it was odd the Z51 would be the performance package and smaller. Maybe this was a mis-type but just what I recall.
I read in a few different areas the rear base actually had the larger piston by 2mm. Recall this pretty clearly as it was odd the Z51 would be the performance package and smaller. Maybe this was a mis-type but just what I recall.
Anyone know why GM would use larger brake rotors on the front of Z51 equipped cars but use smaller piston calipers in the rear?
base rotor front diameter is 12.8", Z51 = 13.4" (5% increase)
base rotor rear diameter is 12.0", Z51 = 12.99" (8% increase)
The rear rotor diameter is increased by a larger percentage than the front, so to maintain the proper modulation and clamping force the rear calipers use smaller diameter pistons. The same master cylinder is used for both systems.
base rotor front diameter is 12.8", Z51 = 13.4" (5% increase)
base rotor rear diameter is 12.0", Z51 = 12.99" (8% increase)
The rear rotor diameter is increased by a larger percentage than the front, so to maintain the proper modulation and clamping force the rear calipers use smaller diameter pistons. The same master cylinder is used for both systems.
base rotor front diameter is 12.8", Z51 = 13.4" (5% increase)
base rotor rear diameter is 12.0", Z51 = 12.99" (8% increase)
The rear rotor diameter is increased by a larger percentage than the front, so to maintain the proper modulation and clamping force the rear calipers use smaller diameter pistons. The same master cylinder is used for both systems.
Realizing this is slightly off topic, it's important to recall that a seemingly small increase in rotor diameter yields a much larger rotor size in terms of area, since A = (Dia/2)^ squared. Mass generally rises with area, too, for better heat dissipation.
I'm sure the base car and the Z51 have nice brakes. The Z51's recently got a ncie review in C&D...
"Not surprisingly, the Corvette and the two Porsche 911s performed very well in this test. We grew weary trying to the get their brakes to fade. All three cars survived more than 35 back-to-back stops from 100 mph without a decrease in performance. That feat is even more amazing when one considers the relatively brief 20-second interval between stops."
I think that demonstrates what a waste of money multi-piston (e.g. 6), fixed calipers are in a street car. Those ol' sliding calipers, combined with big rotors, just flat out work really well.
let me get this straight i have a 2008 A6 with base suspension i would like to upgrade to the 08 Z51 brakes i order the Z51 rotor, bracket kit from GM Parts House and use my stock calipers/pads. now i find out the rear calipers are not the same what can i expect? you would sure think there is some kind of negative trade-off otherwise why did GM use different size bores.
08-04-2008, 10:23 PM
