After my last post, I have been thinking a bit about the shortcomings to my braking system. While the system I currently run (which are Wilwood 4 piston Superlite calipers in the front on 13×1.10″ rotors and 4 piston Dynapro’s on 12.19×0.81″ rotors out back) works very well, my fronts don’t seem to have very much endurance.
Wilwood has been making the Superlite calipers for a long time. I even have some Superlite IIA’s, a much older version, floating around somewhere which date all the way back to the early 00’s if not older. I don’t really know the history or the design goals of the Superlite caliper but I believe it was for light weight purpose built circle track cars. But it just so happen to turned out, the caliper was so good that everyone started to use them on everything. But back when the caliper was designed, 400 hp was considered a lot of power while today its really not that much. Not to mention, how the weight of cars has ballooned.
These days, just look at the brake systems found on modern performance cars. They absolutely dwarf the Superlite calipers and my 13″ rotors. Not to mention the systems that comes on a Porsche; a friend has a 991 4s that has 350x34mm front rotors (that comes out to 13.77×1.33″ for us imperial folks). Its really no surprise that I get only a couple of hours out of my front pads.
A short pad life is not the only issue I have. I also get massive taper in the pads as they wear. The leading edge of the pad gets blasted and wears out much quicker than the back of the pad. This taper is so bad that it actually causes the pistons in the calipers to bind. Luckily, this happens slowly as the pads wears so it doesn’t pose any danger. I feel the brake pedal getting stiffer as this happens.
While this all might sound pretty horrible, its not at all Wilwoods fault. I believe that these calipers were never intended for a heavyweight car with the power I’m making on modern race tires. Tires that didn’t even exist back when these calipers were first introduced. I do know on less intense applications, like a light weight circle track car, the pads wear much more evenly and last a lot longer.
What I really need is a larger caliper with a bigger pad. But, I wished when I got these Superlites I would have gotten the 6 piston version. Those come with differential piston bores and would have, most likely, wore the pads more evenly. I think the 4 piston ones I have now were actually designed for a race series that mandated no more than 4 pistons in the caliper. Live an learn I suppose. I actually chose the calipers I have based off of calculations for my required piston area, and the ones I ended up with were the closest to what my calculations said I needed. Only later did I learn that there is a pretty large margin of error that can be tuned out with the many different pad compounds available. Again, live and learn.
I have found some other calipers out there that seem like they would be a lot better than what I have now. When I was at PRI in 2017, I found a company called Powerbrake. I know… sounds like a ripoff of the PowerStop company, but their products seemed really legit. But, what worries me about a company like that is the pad selection. Everyone and their mom makes pads for Wilwoods, especially the superlite pattern of backing plate. But Powerbrake is an unknown. Their website is also not very good and doesn’t even showcase their caliper and pad selections. I did find an image of one of their setups though: http://cdn3.volusion.com/nryfm.ecyjp/v/vspfiles/photos/NIS01F.3BH.BKD3.X-2.jpg
Wilwood is also making larger calipers as well. Their Aero6 looks very attractive and they even came out with an even larger caliper called the SX6R. But I’m not sure what the intent of that caliper is since they are not currently offering any race pads for them and the pads they do have are only .60″ thick. Typically, Wilwood’s race calipers use .80″ thick pads. I am also disappointed that the calipers only take rotors that are 1.25″ wide. While I don’t think thats a big deal and that 1.25″ rotors are plenty, the OE Brembo’s on the Porsche are significantly wider. I’m really confused to what Wilwoods philosophy is. They do have a really nice thoroughbred race caliper called the Grand National GN6R which uses large pads, differential bores and takes wide rotors. It also has a great selection of race pads. But its limited to 13″ rotors and they only comes in one piston area – a massive 5.40in^2. These calipers are designed for manual brakes and specifically for the Grand National series. While I think this caliper would be great for other applications, like my car, apparently Wilwood doesn’t think so. Though, the Aero6 caliper is really close to this. https://www.wilwood.com/Calipers/CaliperProd?itemno=120-13947
Of course there are other options out there. AP racing, Alcon and Brembo have a great selection, but wow, they are pricey…