BREMBO

[124ADDHE]

The only thing that sucks about the stock brakes is the maintenance required to keep those sliding wedges lubricated. A proper setup system on these cars stops amazing, as redline showed with the numbers.

Im all for a cool addition and those brakes look f-ing awesome but my fiat will ultimately be limited by the contact patch to the tarmac, just like yours.

I uprated my pads to the EBC yellowstuff from Allison auto, they eliminate any risk of sudden, unpredictable brake-fade.

[Special]

The numbers above ...
...don't just eyeball it.

It is not fair - you know all the formulas.
It makes it impossible to argue with you.
I give up.


If I would have the ability to calculate like that - I probably would , but I was just looking at other examples of really week looking mounting brackets -

this one is for Nissan 240



and this one is for some Subaru.



And these cars are a lot heavier then the Fiat and don't have any problems -
so I am pretty sure my brackets will be OK.

[maytag]

... but my fiat will ultimately be limited by the contact patch to the tarmac, just like yours.

A common fallacy.
Don't you know that physics are NEVER a limiting factor in the first-person, as in "My Car"?
It's only in the 2nd or 3rd person that physics start playing a role, as in "Your car", or "Their car".


seriously though; there's a lot more to brakes then just their ability to lock up. Is it possible that y'all have never felt what GOOD brakes should feel like?
'cuz I remember all too vividly test-driving an '83, in '88, at the dealer (Ferrari, Maserati, Fiat, Lotus). This car represents for me the "this is what they were like when new" benchmark. And I can tell you that those brakes were not up to the standards of other sporty-cars of the day. And None of the Spiders I've owned have been any better without some upgrading.

That's not to say they aren't adequate for daily street use: they are.
But to make-out like they're more than adequate is wrong, IMHO.

[fiat218]

The numbers above would indicate that they do not, in fact, suck. 30 years of neglect can make them suck. Porous lines, water-soaked fluid, grotty caliper pins, cheesy pads, a rusty master cylinder. Those can all make them suck. I'm pretty sure the factory rally effort (the first BS-series cars) didn't even upgrade the brakes.

I certainly don't want to rain on anyone's parade, and I think it's great when someone takes the initiative to do something. I really like this particular car, to be honest. But I also think that "big brakes" are a panacea that everyone quickly reaches to, and then there is the surprise that, in fact, those big discs and multi-pot calipers didn't really bring anything. We're talking about an 800kg car.

I retract my concern about the hubs. I had assumed they were re-drilled. Now I see that the OP has "only" made slotted holes to hold the caliper bolts. Interesting. I mentioned it because I think sometimes people don't realize the kind of "power" that is going through these components under braking. Everyone spends a lot of time trying to beef up diffs and driveshafts to take an increase in engine power. Quite often hubs, rotors and caliper backing plates get overlooked. Let's look at some rough calculations (and I may be way off, as I'm just hand-waving it, so feel free to correct me or my logic):
just a question, how do u come up with this calulations?
On original brakes the 124 can pull 0.8g of deceleration, so that's about -7.85 m/s^2

If it weighs about 850 kg, then that means an average friction force of 6670 N to slow it down.

If the brake balance puts 75% of the braking on the front, that's 5000 N on the front axle, or 2500 N per wheel.
(As an aside, I guess the corner weight on the front is about 2500 N per wheel, so that's an effective friction coefficient of about 1, which is consistent with many estimates, so so far the rough calculations aren't complete nonsense)

The rolling radius of a typical 124 wheel is about 295 mm, so the effective braking torque per wheel is about 2500 N x 0.295 m = 735 Nm (540 ft.lbs!)

Now, divide that braking torque by the bolt circle of the caliper adapter plates that have been fabricated and you start to see why material strength and the amount of material you've left are rather important...

Probably they're ok, but don't just eyeball it.

[boogiedude]

Anyone praising the stock setup has never driven a spider with a performance brake kit. Be it Wilwood, Brembos, Tarox, or any other retrofit. The stock brakes do work, obviously, and they stop the car well enough, but that isnt the point of going with a performance kit. The point is to improve them and make the car easier, and more fun to drive. Saying the stock setup is the best answer is ludicrous. A 40 year old, sliding block, single pot caliper is worthless compared to the brakes on even the most mundane, beige, econobox commuter cars.

Good for you Special for making your own setup, it looks awesome and it'll out perform any fool on this site who prefers to stay in the stone-age and preach about archaic technology.

[Redline]

any fool on this site

Well, I respect everyone's opinion. I think most of us were simply asking about whether or not all the details were thought through. Brakes are critical, hence the questions about slotted caliper mounting holes, adapter plate strength and (very important point) matching the master cylinder to the new calipers.

Going with a brake upgrade is a big commitment: new wheels + tires + calipers + rotors + pads + lines + master cylinder + labour. Some were just suggesting that getting the original system to its as-new condition gives a good baseline for comparison (and even an '83 tested in '88 would not really represent "as new" condition; my Opel Speedster with AP Racing calipers, vented rotors and Ferodo pads was always groaning and chirping after <10'000 km and required new pads and rotors by then, and that in an 800kg car...)

Anyway, I really like this tough little "Special" car. Apologies if my comments came across as too critical.

[maytag]

any fool on this site

Well, I respect everyone's opinion. I think most of us were simply asking about whether or not all the details were thought through.

I think Boogie was turning a phrase, rather than trying to call anyone a fool. (I dunno) But let's be fair, Redline. Here's yer sign:

But I also think that "big brakes" are a panacea that everyone quickly reaches to, and then there is the surprise that, in fact, those big discs and multi-pot calipers didn't really bring anything.

I wonder whether you have ever experienced a Spider with improved brakes? Because your suggestion that they "didn't really bring anything" leads me to believe you haven't? I don't know. The ability to lock-up the brakes should not be held as proof that they are as good as they can be. There is MUCH MUCH more to brake technology and functionality than just locking 'em up.

You made quite a point about the stock brakes being "very good". And I think what most of the rest of us are saying is that they are 'adequate'. Not 'good'. And certainly not 'very good'.

But.... as you say, there are many opinions, and we can respect them all.

[Redline]

No, not specifically on a Spider. I've tried good and bad brake "upgrades" on the Miata, Elise and various water-cooled VWs. Some were great, some were a disaster. The ones which were a disaster were usually poorly sized, such that the brake balance was way off, front-to-back, or pedal travel and feel was dodgy (although anything is an improvement over the marshmallow brake pedal in early Golfs and Sciroccos). My comment on big brake kits being potentially a panacea was general, not 124-specific.

I realize as well that Coupe vs. Spider is a bit of apples and oranges comparison, as the brake balance my be different with the Coupe. Spiders (Fiat and Alfa) are more nose heavy that their Coupe and Berlina siblings, aren't they? I'm basing my opinion on the Coupe. The stock brakes, for me, are better than "adequate" for spirited road driving, and our roads don't really give them an easy time.



But you've convinced me to try a 124 with better brakes so that I can form a proper opinion.

[maytag]

......and our roads don't really give them an easy time.

You suck. Man that is beautiful!

I've tried good and bad brake "upgrades" on the Miata, Elise and various water-cooled VWs. Some were great, some were a disaster. The ones which were a disaster were usually poorly sized, such that the brake balance was way off, front-to-back, or pedal travel and feel was dodgy (although anything is an improvement over the marshmallow brake pedal in early Golfs and Sciroccos).

I am in total agreement with every word of that.

[Redline]

Man that is beautiful!

It's only beautiful when you stick a nice Fiat in the picture.

[Special]

This is how one pound of holes looks like

[maytag]

I like it... but does that rotor look waaaay off-center of the hub?

[Special]

Nope .
I just took a picture on an angle.

[unplugged]

Very Nice job. I may steal your idea for my rear brakes. I already swapped out the fronts to one of the "Big Brake Kits".
I had previously changed out my MC and found out the expensive way that 7/8" isn't really close enough to 3/4" that it won't matter. But since you are playing around with different calipers and may want to go with a non-stock MC here is what I used.

Booster: http://www.summitracing.com/parts/SUM-760121/

MC: http://www.wilwood.com/MasterCylinders/ ... 260-9439-P

It has been a while since I installed it but I believe there is an adapter that sits between the Booster and the Firewall. The holes didn't line up with the bolts on the booster but it was a simple matter to just file them a little oval. Once that was done everything just bolted up.

Good Luck

[Kevin1]

Unplugged,
Has the dual diaphragm booster made a difference in how much pedal effort is required? I have Wilwood front calipers and larger rotors. A definite improvement, but getting the Spider's brakes closer to "modern" car power brake feel/pedal effort would be nice.
How does the 3/4" MC help vs. 7/8"? Knowing what you do now, would you do this upgrade again?