Simple (almost) all Mazda Front Big Brake Upgrade

[wytbishop]

OK so you’ve all seen a glimpse of my obsessive compulsive side by now. Once I get an idea I’m sort of like a Pit Bull on a bologna sandwich.

Perusing ClubProtege.com a few weeks ago I read up on the Miata rear big brake upgrade and decided to do it so I have those parts arriving as we speak, but I wanted a similarly easy upgrade for the fronts. There is a thread over there posted by a New Zealander using the front steering knuckles from a E-spec 323F V6 and Subaru Legacy calipers. The problem is that the 323F is a Europe only model and even there it is not common and the cost of getting them here would be prohibitive for most North American owners of the BG chassis and its variants.

So I’ve been looking at stuff trying to figure out a way that this could be done without having to import parts and I think I’ve got it.

I was looking at the 99-05 Protégé Collision guide and I noticed that the basic arrangement of the spindle in the sketch is the same as the MX-3 but with larger spacing of the caliper mounting tabs. So I did some searching.

Here is the 89' 626/MX6/Probe front caliper on the left and the 99’ Protégé caliper on the right...



All we're looking at is the spacing of the mounting bracket mounting bolts. The 626 (GD chassis) caliper bracket is used to mount the Subaru caliper on the BA V6 knuckle so I wanted to see if the Protege seems to have the same spacing and it seems close. So that tells me that the 99' Protege knuckle will probably have the correct spacing to allow the Subaru caliper to bolt up just like the BA V6 knuckle does.

You can also see that the 89-94' Subaru 2 pot caliper looks like it fits in the 88-92' GD Mazda bracket. We already know this but I wanted to illustrate...



Next I was concerned about the hub. The Protege has 5 bolt hubs so would the BG/EC 4 bolt hubs fit. so I checked this...



The 99' Protege (and about 2 dozen others) use the same wheel bearing as the MX-3. So if you could find a set of 99'-03' Protege steering knuckles, press out the 5 bolt hubs, press in the 4 bolt MX-3 hubs install a 270mm Miata front rotor and a 89-94' Subaru Legacy GT 2 piston caliper and mounting bracket (with a couple of millimeters of spacers most likely) from a 88-92' GD chassis it will bolt right on to the BG and EC chassis.

The last remaining issue that may be a stopper is the steering arm. The knuckles look very similar, but it remains to be seen I guess if the steering arm will work with the MX-3...hard to tell for sure from the diagrams...Protege on the left, MX-3 on the right...



I think. All of this still has to be confirmed. So if anyone out there has a 99-03 1.8L Protege I need to know the center to center distance on the front caliper mount bolts.

This won't be an inexpensive upgrade as the protege knuckles will not be readily available at wreckers, but it will be very easy and all factory parts.

What do you think?

[Ryan]

I have a 1999 1.8L Protege LX on my driveway.

[300zxrb26dett]

Hey you stole that post from Clubprotege!

I hope this works cause I can finally have 4 piston calipers on the cheap!

[_-Night-Shade-_]

That's sick, I want to know if it's possible. Let's get to the testing stages!

[wytbishop]

Hey you stole that post from Clubprotege!

I hope this works cause I can finally have 4 piston calipers on the cheap!

Hey I posted it on clubprotege.

[300zxrb26dett]

I did not realize you were the same person. lol


Well for some reason the posts are gone over on CP. I dont know whats up with that.
Anyway I was going to get a BJ spindle this afternoon from a local wrecker for $40 but apparently they had already sold it.

There is another place that has one for $60 locally, but I will have to wait till monday to call them.
For some reason I get the feeling that the BJ spindle is going to be real close to that Probe one I have pictured over on CP.

[wytbishop]

Ah yes. I have many guises.

I am heading to the local DIY wrecking yard tomorrow morning, but I doubt there will be a BJ in the lot. It's too new.

I was planning to ask Ryan if he would mind pulling a front wheel off the one in his driveway and taking a few pictures and maybe some measurements for me. Ahem...Ryan?

[wytbishop]

Here's another thing I stole from CP...I mean posted on CP...

The 00'-03' BJ chassis (protege) all trim levels had the option of 2 or 4 wheel disc brakes. 4 disc cars had 5 lug hubs, 2 disc cars had 4 lug hubs.

The front steering knuckle only has one part number for all cars regardless of brake option so we knwo that the 4 and 5 lug hubs interchange on that knuckle. Well it's the same 4 lug hub as the MX-3 so there's your 5 lug front conversion.

There rear spindle has different part numbers for disc vs. drum brakes, but the MX-3 RS and GS have the same rear hub and I'm betting the the Protege would have the same bearing in both the 4 lug and 5 lug hubs. So there's probably your rear 5 lug conversion.

I have to find a rear 5 lug hub and see if it fits.

[300zxrb26dett]

Here's another thing I stole from CP...I mean posted on CP...

The other advantage to the 5 lug hubs is that opens up even more options for big brakes since there are a lot of cars that use the 5x114.3 bolt pattern.
Almost every 5 lug Nissan, all the way up to the 370Z and Mitsubishi has this same pattern as well. I think the probe/mx6 guys are able to use brakes from a Mitsubishi as an upgrade, either a Galant VR-4 or a 3000GT? So if they can use that, then so could we perhaps with the BJ front spindles. I love all this interchangeability!, Reminds me of working on Nissans....

I am almost positive that somebody with a BG has already confirmed fitment of the front 5 lug hub, and the rear did not fit. I know I saw it somewhere.....
Well I found the thread
http://www.clubprotege.com/forum/showth ... t=lug+hubs

But I think by the sounds of it that maybe the solution for the rear may be just swapping to the rear disc BJ spindle if all else fails. The suspension has the same layout, with the trailing link, TTL's so maybe, just maybe.......

[wytbishop]

So I found an 02' Protege with 4 wheel discs and I had a close look at it. Its really hard to tell. I didn't have the right tools with me to remove the axel nut so I couldn't remove it, but I'm sure of a couple of things.

The strut moung is wider than the BG so that would have to be adressed. I think the arm for the tie rod is shorter and a bit higher than the BG so the steering ratio would be affected too. I have to get my hands on one but it doesn't look good at this point.

It looks like BA V6 knuckles is the only answer for right now.

[300zxrb26dett]

Well it looks like this may not work at all. I did some reading on another thread on CP and apparently someone already tried or was going to try the BJ protege stuff.
He says it too far off. Part way down the post by "Geronimo"

http://www.clubprotege.com/forum/showth ... 040&page=3

Yes BA V6 knuckles may be the only answer. I think for the price though to get some here, I would rather just cut the caliper mounts off the ones we got to make them shorter and go from there.

[wytbishop]

yes you can tell it isn't going to work just by looking at it. I feel stupid now because I remember reading all that.

Back to the drawing board. This thread is dead.

[300zxrb26dett]

I will either try to get some BA hubs or just cut the caliper ears off the BG ones and go that route

[wytbishop]

The quest is not dead, but this path to the grail has come up empty. I will still find a way to make this possible for the masses.

It's what I do.

[wytbishop]

I’m not giving up.

My mission criteria are as follows...

1) The parts must be commonly available and within a reasonable price comparison to a replacement with OEM stuff.
2) The kit must be simple to install. I want no cutting, no heavy tool requirement. I want it to bolt on easily so anyone can do it.
3) I want it to fit in a stock 15” wheel, I may have to go to a 16” wheel though.

The main problems have been:
-The stock caliper mounting points are in the way of all of the caliper options I’ve looked at.
-There are very few 4x100 vehicles with big brakes so rotor selection is very limited.

It’s not so much about the size of the rotor to me...it’s got more to do with getting a 2 or 4 piston caliper on the front to really jack up the clamping force. I looked first at the BA V6 spindles. They are proving hard to find and it’s going to be very expensive to get them to North America. So that’s on the back burner.

I thought I had something with the BJ spindles, but it was not to be.

Then I started looking at a universal caliper like Wilwood. They have some inexpensive options that I thought I could make work but the only rotor I could find that would work at all was the Miata 10.6” unit and it just doesn’t give enough spacing to fit any caliper Wilwood or otherwise without removing or modifying the stock mounting points. You can build a 2 piece 11” rotor but they are very pricey. Anyway, long story short, it was looking like the stock mounting points on the BG spindles were going to screw it up for everybody.

But then I found out last night that the Mini Cooper uses a 4x100 bolt pattern and has almost the same offset as we do. They have vented rotors which are about the same thickness as ours in varying sizes.

They have a 294mm (11.5”) rotor that I don’t think would fit in the 15” wheel but it would definitely fit in a 16” wheel. There is also a 280mm (11”) rotor which would definitely fit in a 15” wheel but may not offer enough clearance for a caliper but I’m confident I can make it work.

I’m working on a few possible caliper options.

The Wilwood Powerlite Radial Mount is ~$145ea, has 0.86 disc opening (the only one Wilwood makes with that disc size) and look like teh sex.

The FC RX-7 had some really sexy aluminum 4 piston calipers which I’m trying to buy on ebay right now. But they’re reeeeally wide so I don’t know how that will work out.

The Millenia and the 89-94’ Subaru legacy both had 2 piston calipers. Not as sexy but maybe better overall because of their reduced demand for fluid volume.

So anyhow I’m still planning on making this happen...just so you know.