johnnymo63

I agree with Mojave. Everyone puts bigger wheels and tires on, but you don't hear anybody too concerned about unsprung weight with those.
Since there are no real differences between the C-5 and C-6 set-ups, stay with the C-5 upgrade since all the parts are proven to work on the C-4.

ScaryFast

Well...I wouldn't say "everyone". I'm concerned with the weight of my wheels, which is why I spent the extra cash for true OEM GS wheels and not AFS replicas at 4 lbs more apiece. Stepping up to a set of Fikse wheels is not in the cards right now.

Tom and I hi-jacked for a more detailed discussion about brakes because the topic of weight came up. We can take it offline if the OP would prefer.

ScaryFast

There is a lot more to it than that, of course. Pad size is one of many components in stopping performance. More relevant are things like piston configuration and quantity, friction material, caliper stiffness, floating vs. fixed rotor, etc. Covering all of the rotor does not really mean anything, you can have the same contact patch with a larger rotor if the pad surface area is the same.

One of the most overlooked parts of a brake package is the caliper quality. The hi-volume Brembo brakes used on many street cars (EVO's, Mustangs, etc) are huge in size, but the caliper body is cast and not machined. It can flex more and therefore trasnmit less of its energy into stopping than an expensive aftermarket Brembo caliper.

But we're only talking street cars here so it doesn't matter, and knowing the full story and deciding whether it's relevant to those asking the question is not important, apparently...

Mojave

Oh man, you are right.

Hey guys, I need to shave a few ounces off of my brake and wheel setup. I lost an auto-x on Sunday because my brakes weighed 6 oz too much.



95% of the people in this thread won't ever exceed the braking capacity of their stock C4 brakes with craptastic parts store pads.

jkade72

So can you run a c6 Z06 rotor with a c5 caliper on a c4? I want the look of the 14" rotor to fill up my 20" wheels.
Thanks in advance

Z51L9889

I have seen them in person in GM's test lab. They are freaking ginormous. I suspect that they are made by Brembo or they are a 6 piston copy made by someone else. They use the biggest single brake pad I think I've ever seen -- the pad area is about a foot long by 3-4 inches high -- no padlets here. I didn't have a tape measure handy to measure the rotor so I laid a notepad across it and it is at least 14 inches.

CorvetteZ51Racer

Brembo, AP Racing, Alcon, and Performance Friction all make brakes that large. When I worked on Daytona Prototypes last year, the caliper/pad/rotor combo was tailored to the track and race duration. We used to have some 12-piston Brembos laying around that carried a single pad approx 12" tall on a 15" carbon rotor. The problem with these things is cubic dollars. A "basic" 6 piston monobloc AP Racing caliper runs ~$6000 ea.

jkade72

Bump....

95wht6spd

So Jeffvette, are you planning on making a kit of the above for C4'S?

Jeffvette

I've been talking to a few people about trying to get my hands on a caliper. The big thing is how they will mount to the new car. If they have a radial mount of a axle mount.

Jeffvette

Yes, the base rotor and the Z06 rotor are both 1.25" in width. All you would need is a bracket to space it out on the diameter.

CentralCoaster

Make sure that C5 caliper (from the 12.9" rotor) will fit over the 14" rotor enough such that the pad doesn't hang past the edge of the rotor.

5abivt

make me that kit to mount the c6z caliper/rotor for my 93 i'll buy it. i have my visa ready

rickneworleansla

After seeing more posts this week on the C4 to C5 brake upgrade I had to come back and read through this one again. Does anyone actually have any data that would suggest the C5 brakes are better than the C4 J55's? Stopping distance, track evidence, etc.. Who has experience with both and which are better? When my pads wear down I was thinking of switching to C6 calipers and rotors. Other than the looks is this a waste of money?

Thanks

Mojave

The C5 stuff is cheaper and easier to work on. C5 front rotors are $20. The pads are decently cheap as well. Instead of having a stupid clip to hold the caliper on, there are just two small bolts. The pads just sit in the PAB instead of being held in with those stupid round tabs. Just for all of that, I think the C5 stuff is worth it. C6 rotors are expensive and different (vane structure is different). I wouldn't bother. I run cheapie C5 style rotors on my track car, and they work really well. I'd recommend C6 calipers with C5 rotors.

Some people have had problems with the base J55 calipers flexing under hard load. The C5 calipers (and especially the C6 stuff) are forged and stronger than the earlier stuff.

steve40th

Rick, I had asked this question to a magazine, as they have the funding etc to try what I wanted to see if this was a valid upgrade, which I think it is as my Vette had regular 12 inchers, then Grand Sport rotors, then C5 rotors etc. The C5s havent warped or cracked and I have autocrossed and run some very brake intensive roads down hills which the stock C4 and Grand Sport brakes warped heavily on.
But I asked if they could basically, with the same car, same tires, same track etc etc, try new 12 inch brakes OEM (same pad compunds), then upgrade to the 13 inch C4 brakes, and finally the C5 brakes systems.
So, same car, same pad compund, same tires track etc etc.
I got no response. But it brings up the point that to truly test wether there is an upgrade worthy here, you need to test all three sets, or more if you want to get into Brembos etc, on the same day same BAT CHANNEL!

Jeffvette

And even when they do the testing they still screw it up.

zaragoza

Here are some shots of my C4 to C5 conversion.

kowalski340

is anyone aware of a company that makes a bracket to bolt up C6 Z06 6 piston calipers up front on a c4 with 14 inch rotors?

Jeffvette

Maybe.