BlackRocket

I spoke with tech at Wilwood and I asked about their 14" rotor 6R BB kit...specifically the lack of piston area. The tech was very informative and stated that there are larger bore calipers that will work with the rotors/mounts but won't work on our cars unless heavily modified. Master cylinder issues and unbalanced with stock rear brakes. He stated that this system is the largest and most effective for stock rear brakes and a stock sized MC. Accordingly, they sold a larger bore caliper to another C3 owner at one time and the owner was dissatisfied as the brakes were too touchy and locked up too easily! Anyways, the Wilwood 13"/14" systems are designed around the C3s weight and stock braking system. I was impressed by his knowledge and overall customer service.

Their 14" 6R system seems like the best bang for the buck at $1,700.
Comments?

Thanks!
B-R

Jason Staley

Are you running R compound or full racing tires to take advantage of the 14" rotors? If not, why not just get a set of Wilwood factory replacements aluminum calipers and stock size rotors. Factory configuration is big enough for pure street tires, cost less, and less unsprung mass too. Just a thought.

OldCarBum

I talked at length with Willwood service reps who all steered me away from their big rotor kits for street and spirited driving use and recommended their 6 piston D8-6 calipers with 11.75 Promatrix rotors for the front and 4 piston D8-4 calipers and 11.75 Promatrix rotors for the rear.
Once my motor is in the car they will recommend which master cylinder will work best with the vacuum I'm making in the motor.
They said their big rotor kits are great for track use but really a waste of money on the street.
There is plenty of room in my 17" wheels and even though they are tight, would have clearance in the stock ralley wheels.

gkull

I have the big front wildwood big piston area, stock master cy, and stock rear calipers with carbon metallic pads. Motul RBF 660 Pro Racing Brake Fluid and bleed it till clear often. Very well balanced with my pad choices on the front. You need to look at the pad TQ graphs. You want nearly linear pads in the heat ranges that it will see on the front

Touchy brakes can be two things. Poor pad choice and or lack of tire traction to use high end braking systems.

I've never had lockup problems, but I understand how to late brake in a straight line and lift somewhat on the turn in. You will see light puff of smoke off the front end inside tire if you are over aggressive

0Todd TCE

Appears the often mistaken piston quantity for piston are miss understanding. All the Wilwood kits in the basic design mirror oe spec piston area. You can do that with one, two, four, six or more pistons. That's quantity..not area.

Clamping is based on area. As too is displacement and bias. Too much area results in a long soft pedal (however greater force for equal pressure) and bias that goes out of whack quick.

You can run small area front and rear calipes with small are masters...or run larger area front and rear calipers with larger bore masters. It's the same thing. Where this goes wrong is miss matching of the calipers to one end or the other and to the master size in use.

You can sub parts and pieces to a degree and get desired results but you should understand the why's an how's of things before making such changes.

Street Rat

I just put some D8-4s on the front of my '81. I liked the looks and the fact that they have o-ring seals. I decided to upgrade from the factory lip seal design which were on my car.

I later found out that the runout of both rotors were out of spec. This was almost certainly the cause of my brake problems.

Glad I put the Wilwood calipers on now. I really honed in on the disc runout problem. New rotors and the calipers freed up some weight. These are quality pieces. They bled easily and quickly.

I'm eventually going to add the rear Wilwood kit. But these things are quite pricy as you know.

BlackRocket

Great input on brake balancing with proper pad selection. I think if I am going to spend the $$ I want the largest caliper/rotor clamping force I can fit inside 18" wheels and will deal with the rear as needed. A proportioning valve may be necessary as well.