I did a quick search here, but didn't find much in this subject, but....

At MOTD, I was told that the oly difference between Justa brakes and S brakes was the brake carrier and the rotor. The S rotor is bigger and requires that the caliper be moved outward.

In looking at parts numbers, I find that S models and non-S models use the same part number. I find differences n the rotor numbers and in the pads.

Given that I will be due a brake job sometime this summer, I'm thinking of accumulating the requisite parts, and, accordingly, I'm thinking of buying S rotors and pads along with the S carriers to do an inexpensive upgrade on my Justa (which seemed a bit lacking in the brake department on the Dragon -- perhaps because its an automatic). I will, of course also be adding stainless steel lines and synthetic fluid.

Has anyone out there actually done this sort of swap/upgrade? Is it worth the approximate $250 cost (carriers are about $120 each - and I'm thinking of doing only the fronts at the start)?

Your thoughts?

After I posted this, I did some more looking and I find that there is actually no difference in the rear brakes sot the only changes will be to the front. I'm going to go with Akebono ceramic pads all around and non-oem disks, most likely from TireRack, most liely Cryostop (dba's are too high).

 

Not sure why you want to replace it. Front rotors are sized to the HP of the car. You may not need the larger diameter rotor for a justa. However, the rotor and pad probably would last longer. It would likely not stop the car too much quicker.

 

Are you talking about a GEN2???? If GEN2 this may be correct.

On a GEN1 I believe the brakes are the same between to S and the Justa until you introduce the JCW brakes, which end up being the same as the GEN2 S brakes.

And Slinger, if everyone accepted your argument (which I'm not saying is right or wrong) Wilwood wouldn't stay in business. For some, size DOES matter

 

Its a 09 Gen2 car, and the reason why I am considering this is because I got a good bit of brake fade on the Dragon. I am thinking that the larger diameter rotor means a larger swept area for better stopping and more surface area for better cooling. And, of course I am optimistic that at some point I will come up with a way to get a bit more power from the Justa naturally aspirated motor.

And, to tell the truth, I'm also a bit of a tinkerer and just like messing around with things, and I thought I might justify this project in my mind (and in my wife's mind) by convincing myself that I am making it better.

 

I dont think you can ever have to much stopping power long as theyre able to stop smoothly and controllably

Hmm so if the calipers are the same, id assume that the master cylinder is also the same? Sounds as if they were sized for rims, not HP lol. There is also the weight of the car in that consideration..

Usually if someone upgrades they go all out and probably do at least the JCWs!..but whoknows

 

I would start shopping the market place, many S owners take off there stock brakes to upgrade to "big brake kits" and no longer need the parts you want.

Things to think about:
If your stock wheels are 15" they will not clear the S brakes -- All S are factory equipped with 16" or larger rims. A few aftermarket 15" wheels will clear the S brakes.

Stopping distance is largely dependent on tires not brakes -- What "better larger" brakes importantly add is "repeatability" --- ie you can stop more often without brake fade with the bigger brakes.

So your problem at the dragon will would be addressed by the change.

 

I have 16 inch wheels now, but I have a set if 17s on the way.

I'd do the JCWs in a heartbeat, but I'm currently suffering from a lack of new excuses to give to my wife about why we need new toys. I about broke the toy bank when I bought the Mini in the first place so I have to walk on eggs. JCW brake projects all run in the thousands. In the case of the "S" upgrade, I have to buy new pads anyway, and S pads are only marginally more expensive than Justa pads -- same with the rotors. And I can buy the carriers for $120 each. I wouldn't have to even bleed the brakes to make this change (but I'm going to because I have a shiny set of stainless steel brake lines to add). So to accomplish this, I have only to justify about $300 to $400 versus about $2000 to go with JCWs. I looked at a lot of brakes at MOTD, but all of them had four digit prices. Too rich for me.

And as far as matching horsepower to braking power, I suspect that the soul reason that the Justa has smaller brakes is so that it can accomodate the smaller stock wheels -- especially so given that there are no other changes in the braking system (i.e., caliper size, number of pistons, master cylinder main orifice/piston bores, etc).

To me it just looks to be an inexpensive way to add braking power.

I'll let you know how it comes out (probably will have to go back to the Dragon to test it).

 

well, I'm no engineer but I've been accused of being one

if you increase the size of the rotor

but retain the pad

and the friction is caused by the interface of the pad and the rotor

increasing one but not the other is BLING and not result.

the larger rotor will deal with heat differently

but you have not increased your braking surface

you HAVE increased your weight up there tho . . .

 

Ahhh, but there's the unknown.

The S model, while using identical calipers, clearly takes different -- and according to those I talked with, LARGER -- brake pads so I'm guessing that the swept area will increase both because of the larger rotor (think about it, the rotor moves outward on the edge so does the caliper, so the number of square inches of rotor area actually does increase, (even with Justa pads). And because the pad is larger, the swept area will increase even more. Therefore, given the larger swept area, and the potentially larger footprint of the pad itself, braking force must improve, as will the cooling. BTW, the backing plate is the same on both models so the only other improvement would be to duct cooling air to the pad/rotor surface -- phase two of the great Justa brake impovement program.

Now, whether or not the improvement from all of this will be either measurable, or, more importantly, be noticeable, well, there's the quandry.

I'm willing to bet the requisite $300 to $400 that it is both.

Who knows, I may be all wet, but the worst that can happen is that I will spend a few hundred to come up with nothng but "S" brakes that are no better than my original Justa's.

And thre is no "bling" effect. The brakes are identical in looks once the wheels are in place. I'll have a problem keeping the local Mini shop from putting the wrong pads on the car if I ever take it there. They'll never actually see the difference unless they measure the rotor and look at the caliper part number.

I guess I could paint'em purple or something, but I'm more interested in function than appearances.

The increase in brake drag will no doubt be a factor, but remember, I'm not so much interested in that issue as I am in getting improved braking and less fade. I could really care less if the car is incrementally slower as a result. I have sufficient power to overcome that issue. I'll probably see larger friction losses from the increased contact patch that the 205-45/17s will provide.

In the end, I can't lose -- either way I get good brakes. And I get to mess around with a noble experiment. The worst that will happen is nothing at all (and I can always put everything back as it was).

This is sounding more interesting all the time.

(BTW, I'll deal with the weight issue by using lighter wheels and tires -- it has realatively heavy 16" Bridge Spokes and really heavy Bridgestone run-flats on it right now.)

 

I was not too clear but I felt that it is unnecessary to swap brakes and rotors if you do not use it for the track. Just changing out the brake pads would be enough for most situations.

 

meh. might as well do it just to do it. THEN get aftermarket S pads!

Even us S people upgrade all the time to JCW or bigger and im sure some of em dont see track... kinda the same...

The OP stated the brakes were lacking...whos to say itll never see a track lol

 

Of course you can do it. All I am saying the benefits are not great for a street car. You can probably get as much from a good pad change. Many people put things on their cars that is bling.