In Defense of J55 Brakes

[LGAFF]

First, Big brakes look awesome... certainly over high speed repeated stops there is a clear advantage, I have 8 piston Brembos on my SL600, and 6 Pistons on 3 of my other cars. My 91 ZR1 at one point had Brembos from the Porsche 993 but the prior owner sold them... so I was looking for a brake upgrade.

I had landed a set of C6 Z51s cheap, so I thought throw them on the Z... well that didnt pan out the Z51s dont clear stock Amold sizes. As I started to look at options I did some checking on the J55's performance. From 70 it drew the LT5 down at 170ft... when I looked at the C6 Z51 the number was anywhere from 152-160+. So I asked myself, how much better is the C5/C6 caliper when its stopping a Z06/or C6 that weighs 200lbs less than a Z in just 5-15ft. I never noticed this but the standard c4 was the first corvette to hit below 110 from 60

Even the best braking cars in the world currently are in the mid 140s, some 130s for stops from 70.

So when you consider advancements in tire and pad compounds since the 90s, you could easily get your J55s into 150s with Hawks or EBC pads... better tires could even up the ante.... So the J55s no slouch..... I think Im staying with them.

[Ccmano]

I couldn't agree more. J55's are way under rated and with modern high performance pads they really perform well. When I installed my GS J55 calipers last year I opted for PowerStop Z26 Street Performance pads and rotors. The difference from stock pads is remarkable. C5/C6 Calipers have little advantage over a good J55 setup. Larger calipers like the C6 Z06 and other Brembo, Wilwood or Baer setups are good, but for the cost and installation headaches (parking brake) they are only an advantage if you track or autocross the car. But hey, if people like the look or feel the need for every ounce braking performance they can spend their money however they like! It's still a free country (for now).
H

[1991 Corvette ZR-1]

Originally Posted by Ccmano

I couldn't agree more. J55's are way under rated and with modern high performance pads they really perform well. When I installed my GS J55 calipers last year I opted for PowerStop Z26 Street Performance pads and rotors. The difference from stock pads is remarkable. C5/C6 Calipers have little advantage over a good J55 setup. Larger calipers like the C6 Z06 and other Brembo, Wilwood or Baer setups are good, but for the cost and installation headaches (parking brake) they are only an advantage if you track or autocross the car. But hey, if people like the look or feel the need for every ounce braking performance they can spend their money however they like! It's still a free country (for now).
H

I went with the same brake pad/rotor set up from Power Stop, complete with a full fluid flush. I?ve found the Z still doesn?t shed the speed like I thought it would. I?ve been spoiled by of all things, an old 2000 F body a friend drove in college with factory braking system. I got to drive it a few times and if you just breathed on the brake pedal, you could feel the brakes really bite. With the Z, I feel like I have to roll into the brake pedal and apply a decent amount of pedal push to slow the car.

[LGAFF]

I think a lot of it is pedal feel vs actual results... electronic brakes make a huge difference in pedal feel

[LGAFF]

Car and Driver 2009 ZR1, Z06, Z51 Test

From 70

ZR1= 141
Z06= 150
Z51= 152

So a C4 ZR1 with the J55, EBC/Hawk pads and modern rubber would probably be right in the mid 150s

[Erik]

I never got the knock against the J55's. I can't imagine upgrading from them unless I was doing really serious track work.

[LGAFF]

I orderd some EBC red stuff pads, and will install the bias spring and see how they do

[tgonyaw]

I would be interested in seeing your results also. Road surface and tire configurations at play also. My car is mostly stock with full depth street tires. I think a well maintained J55 set up is all I need. Thanks doing the testing.

[1991 Corvette ZR-1]

Originally Posted by LGAFF

I orderd some EBC red stuff pads, and will install the bias spring and see how they do

Interested in this result. I have stop tech pads but maybe trying out hawk pads might give me more of the grabby bite I?m anticipating in my head.

[LGAFF]

We put EBC red stuff pads on my wifes CLA45 it stops from 70 in 150ft stock, the pads have a lot more initial bite than the benz pads and zero dust