Brake conversion

mk2-1jz said:

around 27 mms needed in the front to fit the caliper

Click to expand...

So is that 27mm clearance needed on wheels from the hub mounting surface to the spokes of the wheel? Raj figured we could get another 2-3mm by clearancing the letters off the calipers. Were those the aluminum or iron 30mm Z calipers? Looking at those comparison pics Raj posted, it almost looks like the aluminum ones might be a little thinner in width as the casting around the piston holes is much closer to the edge on them then on the iron ones. Also, with the rotors thickness taken into account, if your around 10mm off from the clearance you need just run some long studs and a spacer if you really want the Starion wheels. Chances are they could stand to come out a bit more anyways. Try my celica GTS steering arm mod too if they stick out too far once you get them clearing the brakes. Those arms suck in the struts about 10-15mm. To give you an idea, I run 15x8 -12 wheels on the front of my car with a little negative camber dialed in and 225/50-15s and they are perfectly flush with the flares.

Basically I want to know the max spoke depth clearance I need. I've got 2 sets of wheels I'm planning on running on my car, preferably with the 30mm aluminum z32 calipers and some rotors that can be mounted like stock. I'd rather not run any spacers but I can change my plans a little if need be.

So are you running the NA calipers then? Those are 26mm, the turbo 30mm, but the MPV rotors are 28. Dude a couple pages back ran out of pad with his mismatched rotor and caliper thicknesses and almost wrecked, have people successfully run either caliper?

Regardless, my issue with over rotors is the same as Billy Ms from years ago (I've almost read the whole thread now lol). I'm not willing to add the weight of the center section of an over rotor unless I'm going to simultaneously switch to a new hub that is designed to work with over rotors and is significantly lighter then ours.

Honestly, calipers are easy. I don't mind making brackets, the issue is a I want a decent sized (read significantly, but not exorbitantly, larger then stock rotor rotor) that bolts up to our hub. I do prefer easy to change rotors, but not at a significant weight expense. I've been running the same set of rotors and (ceramic) pads for 10 years on my car, frequent rotor changes are not a concern. I would just bite the bullet and go JK as I know they clear my wheels (yup 15s even), but A) I would have to switch to T3 steering arms then (I have celica gts), and B) I don't like the idea of running rotors and pads that I can't just get through any old parts store. Plus I only need upgraded front brakes. JKs are such a big step up I would end up doing the rears too then.

So, I could have sworn that at some point in time on this board I saw someone with a front BBK setup with bolt on rotors. I thought they were the PT cruiser ones, but now I'm not sure. Has anyone ever successfully bolted those on? I'll have to look up the specs on those next. Or has anyone else ever found another bolt on rotor? Obviously redrilling the mounting holes on the rotor would be expected. And don't say cressida, not big enough.

Guys don't sweat my 15 inch wheels. Like I said they clear JK brakes, which are bigger then the MPV rotors.

I should also mention, not only am I a weight weenie, I am a mono block snob too. There are several monblock 4 piston calipers that meet my criteria, but I will probably go with one of the z32 ones just for the awesome pad selection they have and the fact that the caliper bolt spacing happens to be the same.

Gamble, I assume you are talking about the later mx73 rotors. As I said, not enough of an increase to interest me (plus long term availability will become an issue). Mx8x Cressidas probably have big enough rotors but as I recall they went to over hub rotors on those? I'll have to check that again.

Revvhappy, stock pad selection is fine, I love my pads! In fact I've been out stopping big brake equipped cars with my setup for a long time. But in recent years as I've made more power and gotten faster, my brake setup has started to show its shortcomings. And I definitely need more rotor mass if I want to get serious about track days. Your rotors are 28mm wide aren't they?

So the mx83 front rotors did go over hub, its the 88 mx73 rotor that was coming up in my searches. Its specs...


The 85 Supra rotor for comparison (basically same as mk2)...



So a decent upgrade for the cressida over the earlier rotor, but but pretty poor for the mk2.

Ha ha, maybe I'm just super picky, or stubborn.

In my research I've looked up the following info, could be useful for others exploring other rotor options;


1990 300zx NA front rotor. The one designed to mate to the 26mm caliper that many of us have gone with.


1996 300zx Turbo front rotor (90-96 should be the same). The rotor for the more common 30mm caliper.


1996 Mazda MPV front rotor. The one that everybody uses.


Outer Diameter:308mm (12.19 inchs)
Normal Thickness:32mm (1.25 inchs)
Jim King mk2 BB Kit front rotor.

Anyone weigh one of those bad boys with the aluminum centerplate and 8 bolts and nuts needed to attach them to each other?

I've been using autoparts warehouse to look this stuff up as they seem to carry standard centric rotors for every application and they always have the diagrams.

Nope, its worse!

Found the mk2 Supra's spec sheet on the actual centric web site...


With the MPV rotor thats a 7.25lbs increase of pure centrifugal mass per corner, for a somewhat tame sized rotor. No thanks, I have found several better alternatives already. Almost done my research, more to come soon!

Still looking for answers to 2 questions in that last post, but I have another for the general populace here...

So hats off to Mr Jim King. Going with the calipers speced in his Wilwood kit is a great choice. I have found a large range of rotors that meet my criteria but so far no 4pot monoblock caliper off a regular production car that is slim enough to mount to a rotor bolted to our hub that can clear old school wheels without at least a 5mm spacer. I've found interference specs for several calipers and none, even with modification will do it. Before I spring for a set of 26mm z32 calipers and resign to spacers, can anyone think of any others? My criteria is; must use pads that were available on a production car sold in North America ( I want to be able to get pads on long distance road trips if need be), must be a 4 pot monoblock design, must be designed to work with a rotor between 280 and 310mm in diameter, must weigh 10lbs or less (so aluminum ) and needs to be less then 68mm from the center of where the rotor would sit to the outer edge that would be closest to the wheel spokes.

I have looked at the following front calipers;
Z32 26mm and 30mm.
FD Rx7 (3rd gen)
All calipers from Double wishbone Toyotas and Lexus LS/GS/SC models
Subaru Wrx 4pot (06/07), used on other models and markets too

They are all around 70-75mm and interfere. Any ideas guys?