Wilwood D-52 Caliper question

[Nicks67GTO]

Does anyone on here have them on their car? Has there been any independant testing done on these vs. old style stock D-52's? Do they really pull the car down much quicker than the originals or are they more for 15" wheel bling?

[ProdigyCustoms]

We did them on one of our drag cars, 140MPH through the traps. No scientific test results but surely feels like it stops better in a short stopping distance.

[sr73bu]

I have them... the (2) 2" piston versions for the front brakes. They are quality pieces, light-weight and the fact that they are larger and billet aluminum will probably help dissipate heat better than the old cast iron d-52's. I've read that the wilwood BP-10 pads that come with the kit don't bite as well or are really as effective as other pads on the track or for aggressive street driving. So I swapped them with EBC yellowstuff pads (these pads alone make a difference, pricey though). A guy name ROD on here swapped pads (same calipers) and from what I read it made a huge difference.

Check my build thread for pics and after April 2nd I'll give you a full review on them...I'll be running my car on the road course at RTTS in NJ... my car weighs 3850 with me in it, so it definitely will be a test...

-Sean

[Rod]

the wilwood D-52 replacements work well and really come to life with wilwoods own E pad for them. The grip was awesome and the brake fade level must be very high! I just ran them at the Run to The Coast II event and on the big track the brakes held tough for the 2 solid days of abuse and they never gave out or faded!

[79-TA]

The brake caliper's job is pretty simple. It has a total piston area which determines part of the hydraulic force multiplication ratio. The caliper is also responsible for dissipating some heat, but not nearly as much as the rotor. As mentioned above, the newer D52 has two pistons with 2" diameters. That's a total area of 2pi or about 6.28 in^2.

When I did the brakes on my Trans Am last weekend, I measured my stock caliper piston and it was about 3" in diameter. That gives a total area of 2.25pi or about 7.07in^2. The D52's will then offer 8/9 (2/2.25) of the braking force that the stock calipers did. This is not the end of the world though. One can still adjust the front/rear braking bias with pad compound. With some pad compounds, you might actually be glad you have a bit less braking force (as the brakes might feel too grabby or touchy.) Switching to steel braided brakelines might also improve pedal feel. It is also possible that the rear brakes were underutilized before and the balance has been improved. However, the car should always always have a brake bias that favors the front for the sake of stability and safety.

I have Hawk HP+ pads on the Trans Am paired with Powerslot Rotors and the combination works wonderfully. However, the The biggest track the TA has run was the one at RTTC which doesn't have any super demanding braking zones. My Mustang on the other hand runs a similar setup (it uses Hawk HPS pads instead of the +'s) has run the Cal Speedway Roval (4 big braking zones) and the brakes worked very well. My point here is that calipers are not the highest priority when it comes to brakes and brake feel. I'd rank them as follows:

- making sure the system is bled properly and not leaking (kinda goes without saying, but I thought I'd include it anyway)
- brake fluid - ATE super blue is affordable and it's just silly to have boiling brake fluid
- pads - lapping a track requires a pad that is designed to continue providing a high coefficient of friction at higher temperatures
- rotors - rotors are responsible for storing a dumping the vast majority of the heat. A basic performance rotor should be built to better handle the heat
- calipers

D52 Pros:
- some weight savings
- brand new internals that should be less likely to fail and are supposed to be more resistant to corrosion
- a bit better heat dissipation
- flashier looking brakes

Cons:
- less piston area than stock means slightly less braking force
- existing caliper might be perfectly capable while money could have been spent elsewhere (for instance, my 32 year old Trans Am caliperes have not corroded to the point of failure)


So to answer your original question, no because they provide less braking force.

However, it's not a big enough difference that it would prevent one from bringing the tires to the limit of locking up, so in that regard, no, it'd be about the same for ultimate braking force.

Then again, if the rears were noticably underused and balance has been improved, then yes, they car would stop more quickly. How's that for a conditional set of answers?

Most automotive braking systems do not lack in ultimate braking force. What matters is whether the system can handle large amounts of heat well enough to resist fade.