Precision 2-piece rotors and RZ/Wilwood/Widefoot rear brakes
 

I finally installed the Precision Brakes Company 2-piece rear rotors in the Mazda RS/RZ size (larger than U.S. model) with my Wilwood/Widefoot rear brake setup tonight (see: http://maxcooper.com/rx7/how-to/brakes/rear/index.html). They Precision rotors work just fine with this setup and there is plenty of clearance for everything. In fact, the Precision rotors are a bit better than the Mazda rotors because the bottom of the pad hangs over the edge of the friction surface with the Mazda rotors and gets full contact with the Precision rotors. That gives a little more swept area than the Mazda rotors. I had to file a bit of the pad off where it was hanging over the edge of the Mazda rotor when I installed the Precision rotors (easy to do, and I didn't want to gouge the new Precision rotors). New pads won't require any filing -- it was just the part that was hanging over the edge of the Mazda rotor's friction surface that I removed, since it was thicker than the rest of the pad.

I did a test drive (and bedding run) after the install and they work great. With the 13" AP fronts and the 12.2" Wilwood rears, my car stops like a mofo. :D

I'll post some pics soon.

-Max

P.S. Thanks again Jim for the rotor fastener torque specs, assembly, and bedding procedures.

I took some pics tonight. They are lousy pics and in the dark, but it's proof that the parts work together with an easy-to-recall picture if anyone else is considering a similar rear brake setup.

And before anyone mentions it, yes I know I need to clean my car/wheels/etc. I just got the car back from a long rebuild/upgrade and I'm just trying to get everything sorted out first. Function before appearance.

-Max

Hey Max you didn’t happen to do any rudimentary brake distance testes, just to compare the 0-60 (or whatever) stopping distance did you?

Obviously they should not fade as much with hard use, but just wondering if they had ay side effects of better stopping distance.

they look good by the way:)

I don't have any "before" tests, so I don't have any way to compare. A common point that comes up in all the brake upgrade threads is that so long as you can lock the tires, big brakes aren't going to help your stopping distances. So I wouldn't expect any significant difference in 60-0 braking with my setup versus stock. There is probably a fair amount of variability (weather, surface changes) that would be hard to eliminate from the tests, too, so any real difference would probably be less significant than the general test variability. The only advantage I could imagine would be from better bias, but even that would be small since the fronts do the vast majority of the work when braking hard. And I don't know that my setup has better bias than the stock system (also, bias varies from car to car based on ride height, weight distribution, tires, etc.). There might also be some negative side effects with my bigger brakes versus the stock brakes in that the ABS controller might do a better job controlling the stock calipers than my bigger calipers. I haven't noticed any significant problems with the ABS control, but my butt-brake-dyno isn't precise enough to detect small differences. If there is a difference due to the ABS, though, it isn't large.

I am very happy with my current setup. The pedal feels great and is easy to modulate, they release cleanly, and the bias feels generally correct. They have also resisted any "warping", too, which is nice since I used to have a lot of trouble with that with the stock brakes. I am sure they will be more resistant to heat-related fade and inconsistency that I have experienced with the stock setup in extreme conditions. I am hoping the pad and rotor costs will be reduced over the stock system, too, where I used to kill rotors fairly frequently and track pads only lasted one weekend. I haven't been to the track yet to test the big brakes out yet, though, so I am just speculating at this point.

-Max

Just subscribing to see how these turn out. I probably won't go with the Wilwood calipers, but I'd like to go to the 2-piece rear rotors.

i don't know what you're talking about, i think these may be the best quality pics i've ever seen from you :). your setup looks great, keep us posted on how you like them once you get some track time in.

Yes, I finally got a new camera, so my pictures suck slightly less than before. :D

I'll report back with track impressions once I have some.

-Max

Looks great Max! I finally got around to installing my 2 piece rotors with the RZ front and rear calipers as well. :bigthumb:

Pics, pics!

-Max

no parking brake right?

My setup with the Wilwood calipers has no parking brake.

Using the Mazda RZ rear calipers keeps the parking brake.

-Max

I take after you with my photography talent! :rlaugh:
http://img192.exs.cx/img192/1020/im0007452au.th.jpg
I'll get some better ones as soon as it gets warmer.

here are some more for you Max. Rears for right now, waiting on dust shields before installing the front :D

https://www.rx7club.com/attachment.p...hmentid=102268

https://www.rx7club.com/attachment.p...hmentid=102269

Bringing this back from the dead (5 years!) - 7 racer - I see the hat is installed on top of the rotor - I assume the rear dust cover had to be completely removed. On mine, if I install the hat on top of the rotor - it is much taller than the stock rotor - i.e. placing the rotor closer to the center of the car - and offsetting it from the rear brake caliper.
I have 99 rear calipers,(brand new), and the precision brake setup both of you guys have,(hat and rotor).
Any other pictures?

Thanks! I did read the link and grinding off that much material off the original cast caliper mounts for their adapter, would make me look for a diffferent adapter bracket or weld a plate to the aluminum upright for the caliper mounts. Excellent write-up and pics. Very detailed.

They do make hydraulic park brakes. Sand buggies use them. Press the brakes, press the valve in, release the brakes and it holds the fluid in the rear brakes.

GD