I just mocked up a front rotor from a 95 Mazda Millenia on my 3rd gen with a J30 dual piston caliper. Clearance is close but it clears with a 2mm washer between the torque member and the knuckle. The center bore of the rotor is bigger and gives about .5mm or so of play when on the studs. Even with it as far to one side as possible it cleared the caliper as I turned it. I haven't driven on them yet to see if I can notice a wobble or if its out of balance. The rotor is 274mm vs 280mm for the Z32. They are both 28mm thick. These rotors with a washer save the trouble of having to mill off 3mm of radius on the Z32 rotors. I will however have to grind off a small portion of the metal on the outside pad towards the hub. Not the pad itself, just a bit of the backing.

I assume fitment is similar for Z32 and Q45 calipers.

Someone (Matt, Jeff) please advise if adding a 2mm washer between the caliper and knuckle is a bad idea and if having .5mm of play in the rotor is a big deal (the rotor wont move once the wheel is mounted).

I'll add some pics after I get them off the camera and uploaded. I'll try to get both sides mounted and go for a ride within the week and will update. If it doesn't work I'll delete this thread in embarrassment.

edit with pics:

 

Interesting. I offhand, don't see a problem with it.

 

Success! I had a couple of issues one being the one shown above with the outside pad. The grinder took care of that pretty quick. The other was the hardware that holds the pad rubbed the outside of the rotor. I bent the tabs back and forth like a paper clip until they broke (pics to come soon). Hopefully they wont move left and right too much. I made a few laps around the block to bed the pads and all feels good. After tweaking the hardware on each side there is no more rubbing or grinding noises.

cliffs: 95-96 Mazda Millenia rotors work with J30, Q45 calipers with slight modification to the pads and hardware and using a 2mm washer between the torque member and knuckle. The rotors should also work with a Z32 caliper but I'm unsure of the fitment with the pads. Someone try it and find out.

Pad before grinding:


Pad after grinding:


Fitment:


Modified hardware left, OEM right:

 

so with the j30 calipers you don't need the brackets for the j30 calipers? We can use our caliper bracket for the j30 calipers if I use the mazda rotors?