My Budget Big Brake Kit using Corrado rotors
 

My Budget 11" Big Brake Kit….. Installed on 90 Mazda Miata w/ 15 wheels.

Parts List:

2 1990-1991 Corrado front rotors – Napa part # 4886122
2 Front rotors from Miata (used to make hubcentric rings)
1 Front / Rear set of your favorite brake pads for a 1.8L Miata
1 Wilwood Proportioning valve – 260-8419
4 Grade 8 flanged bolts to mount caliper bracket
4 Grade 8 all steel locking nuts
4 M12 bolts to mount the 1.8L caliper brackets (original bolts are incorrect grip)
1 ¼ chomoly plate steel for caliper mounting plates.

Optional:
2 1.8L Miata Brackets ( for those with 1.6L brakes)

Step 1: Make hubcentric rings and turn down head of 2 Grade 8 bolts.
Take a new rotor and a pair of old rotors to someone with a lathe. Bribe them to cut rings from the original rotors that fit inside the new Corrado rotor. Also, have them cut the head of the bolts down to fit under the caliper brackets (see picts) You may need to clearance the caliper bracket to allow the most material for head bolt.

Step 2: Ream/drill the caliper holes on spindle to fit the new Grade 8 bolts.

Step 3: Cut out mounting plates using downloadable pattern. Drill the holes on a drill press only. I would start by drilling 2 of the holes to size, 2 slightly undersize, then mount on spindle and ream to final size for a secure fit. Alternatively, If anyone wants to put this in AutoCAD step up :)

Step 4: Mount bracket to spindle, bolt rotor to hub, mount caliper bracket. Check fit between both faces of rotor and bracket to rotor OD clearance. They should be even. If not, determine why and correct.

Step 5: When fit is good re-assemble and torque with green locktite.

Step 6: Install Proportioning valve. Bleed brakes, set front to rear bias and enjoy.

Disclaimer – this is provided as educational only. If your brakes fall off this is not my fault. Do not attempt if you are not skilled in this area – get help.

Pictures of hubcentric ring. I would have it cut straight across on the OD of the ring... keep it simple, unlike the pic.

Mounting plate installed...

Caliper bracket mounted to mounting plate.

Bracket pattern file. If anyone with CAD expertise wants to clean this up and verify it would be great.

that would be great, I'd buy a set of them too.

Question: Is there a reason why your 1/4" bracket "rotates" the caliper bracket? Cause that's gonna make it a bit crocked. Curious why you did it that way. Awesome that you wrote this though, many thanks. Not sure I like how much you had to cut off that one bolt head though. Looks pretty weakened.

looks great but try to redo that bottom bolt looks weak u dont want a weak part on brakes

ill try to do that up in cad on my spare time (end of the week).

edit: couldnt open that file, idk what program u were using. I use autodesk inventor. Just try to post up a screenshot of the 2d dimensioned drawing and ill make one in autodesk inventor

I'll see what I can do with that cad file at work tomorrow if i remember.
Instead of trimming that bolt down I could machine some of the caliper bracket away instead. Split the difference between the two.

I'd like to see a picture of how the hubcentric ring sits on the hub and how the corrado rotor interfaces with the ring to be centered.

hey how big is the rotor compaired to stock? any pics of it done?

I wonder if the angle of the caliper is to tip the pad some so that it covers more of the larger surface area of the rotor. So instead of using the 1.75" tall pad surface you use more like 2-2.2" of pad height.

btw... i found in his other post, corrado is 11" stock 94-2000 is 9.9"

Would really like to see someone like M-tuned make a kit for this. Include the hubcentric ring and a bracket bracket design. It's a great idea and I know it's been knocked around. If you could buy a pair of brackets and the rings for under a hunsky plenty of people would do it. Better yet would be a 4 wheel kit to keep the brakes balanced.

here it is done

The pads sit 'square' relative to the rotor. The bracket was rotated along the spindle centerline in order to use this with 15" Konig Helium wheels. Rotor is 11" 1/32. IF I mounted the bracket directly above the original holes it sticks up a little to much. I wanted to avoid cutting down the spindle and bracket.

A side benefit may also be the intersecting lines between each pair of mounting holes. Theory is there is less leverage for this to bend. But it is only a theory.

I agree the bolt head is not ideal, and splitting the difference between some clearancing in the factory bracket is best. But most of the force is in shear and to rip the bolt in tension you would also have to also break all 4 wheel studs and rip off the rotor before the bracket is compromised. Its good the caliper floats.

The the od bevel in the hub centric ring fits the bevel on the backside of the Corrado rotor. But the Corrado rotor also has a flat surface that is sufficient to located on a straight cut hub centric ring. I guess the machinist wanted to kill some time lol

Yes, a kit with brackets, rings and hardware would be awesome. But for me its not worth the risk of getting sued. A business on the other hand has insurance :)

Im sure this isnt even close to scale....

but this is:

awesome. ill make that into an autodesk file later on and do a cool rendering

We have the prototypes made, and are waiting to get them put into a CAD file.

Braineack.... wow! Are those from the dwg file?

If so, please verify the distance between centers. The guy who originally did it was a little off on the holes when pattern was printed and compared to actual plate.

If not - You rock!