EvilBoffin

I'd love to hear your comments on my initial plans for brakes needed for HPDE's in my Z51 C6 -

• C5 NAPA rotors (front)
• C5 caliper brackets (front)
• Wilwood H or Carbotech XP10/XP8 pads
• ATE SuperBlue or Type 200 fluid
• C6 Z06 brake ducts
• Motive Brake Bleeder

The biggest question is - should I also replace the stock Z51 REAR rotors & brackets, too? Or, just get rear pads that fit the stock (cross-drilled) Z51 rotors that work reasonably well on both track & street?

I intend to dedicate these front pads & rotors to the track, but I drive the car on the street, and to/from the events as well.

THANKS !

Rob Burgoon

I did the rears also, just so my rotors didn't look silly being plain up front and drilled in the back.

EvilBoffin

ttt

Rob Burgoon

To better answer your question, that would be fine. The rears don't do much braking, and having too little rear bias wont cause stability issues like too much rear bias would.

Keep your cross drilled rotors and either keep your Z51 pads or put C5 Z06 pads back there. Then you can swap in something stronger up front as necessary.

Better answer?

EvilBoffin

Thanks for the responses, Rob.

Unless someone offers a differing viewpoint here, then you have confirmed what I thought. I can always add the rears later if deemed necessary.

I just wanted to ensure that those expensive, cross-drilled rotors wouldn't still crack back there, or that changing only the fronts wouldn't alter the brake bias/handling feel in some weird way, under such heavy braking conditions.

Rob Burgoon

Under heavy braking you lose out on a little extra braking power with the rears fading first.

The only risk is if you end up with race pads up front that don't work when cold. Then on the way to the track with cold pads you could have a brake bias to the rear.

That might only be an issue with extreme race pads though.

tmak26b

The C6 is a very front bias heavy car, I have a tough time preventing the front brakes from locking. You might have the same problem.

yakisoba

I'd do the rears too, just to keep everything the same and wear on your stock parts the same.

gkmccready

I disagree. I ran PFC 01 fronts with PFC Z compound rears for a number of events, and when I switched to PFC 01 fronts with Wilwood H rears my braking performance was MUCH better, and quite a bit more balanced.

The other thing I've noticed is that the Wilwood H pads on the front are much more linear during application than the PFC 01. Looking at the pad curves for the PFC you can see the Cf goes up with temperature so during application the PFC stops more and more without you changing pedal pressure! You can get used to it, but after putting H pads on the front I sure like that feeling a lot better.

EvilBoffin

Mr. McCready - Are you saying that you prefer to run C5 rotors front AND rear, with Wilwood H's on both ends as well?

As you can see from my initial list of parts above, I had the Wilwood's in mind already, or the staggered Carbotech set (XP10 front/XP8 rear) to get a bit more rear bias. I just don't want to be replacing rotors constantly from overly-aggressive pads, so I'm not sure which would be better...

Good point, I've also been weighing the 'even wear' issue against only having one set of rear brake parts. Having no spares could be a problem if there's ever an issue, which could end a nice track weekend prematurely.

THANKS guys, for continuing this thread - it's a good discussion.

kflee

To be safe, you need to do both or none... By doing the front only you significantly change the brake bias rearward. This is because you are reducing the moment arm (leverage) of the front brakes by 0.5" (1" smaller rotor).

The vette may could use a little more rear bias, but that may be too much, potentially making the rear end skidish under hard braking.

As for pads, you should always run the same or very similar compounds front and rear. They need to have the same friction vs. temp curves.

Kirk

Rob Burgoon

Crap, you're right Kirk, I forgot about that part.

Bill Dearborn

I doubt that will make much if any difference. You forget the later C5s and the C6 all have dymanic rear proportioning. The brake system will apply as much rear brake bias as the available rear traction can take whether the rotor is larger or smaller.

Bill

kflee

Dohhhh...

You are right, I did temporarily forget. All this new-fangled technology takes all the fun out of modifying a car. If I now remember correctly, it actually looks at the rate of speed difference between the front and rear wheels, not just when the rears lock... I wonder how effective it is???

rbl

Unless you're running some serious rubber why bother with any of it? Put the PFC "Z" rated pads on the car and enjoy it.

Folks here don't think much of the Z51 drilled rotors but I will guarantee you they will outlast the C5 rotors 3 to 1 and they only cost 2x.

Additionally, the XP-10's and XP-8's aren't much, if any, better than the PFC Z's.

Save your $$ for an extra event instead.

gkmccready

I chose to run C5 rotors front and rear because of (a) price, and (b) no cross-drilling. I tried the H pads after several folks suggested them, and find them much easier to modulate than the PFC 01 pads. And, for me, running a race pad front and non-race rear didn't make the car feel nearly as good as race pads front and rear... also, running the race pad in the back seemed to help brake wear (pad _and_ rotor) up front.

All of this is subjective so you'll just have to try it and see. I've watched several folks now run C6 Z51 cross-drilled rotors. Haven't seen many folks do it with race pads, though.

EvilBoffin

Thanks guys.

Wilwood H's seem like a well-liked pad. Though, this is the first time I've heard a 'bad' review of the XP10/XP8's...

Any suggestions about where to buy the *******?

tmak26b

I ran xp10 on my stock c6 z51 rotors, seems to work okay. THey are rotor friendly compare to the HP+

rbl

Exactly, and that is why they are no better than the PFC "Z"'s. You can't have it both ways on being rotor friendly and being aggressive.

And CrystalRacer got it wrong .... there was no "bad" review about the XP10/XP8 pads. Carbotech makes good pads IMHO. However, the XP10/8’s just are not much, if any, better than the PFC's, which are very good for all around use. If you don't have any rubber that will be the limiting factor.

tmak26b

I can't relaly test the limit with these pads on my C6 because i am on street tires. If I hit hte brakes hard, ABS would just flip out.

I had them on my 350z, stopped the car from 60-0 on the RA1 in 107ft. I dont think they aare bad parts. I can tell you they are AGES ahead of the HP+.