Bigger brakes

speedy fiat

True Classic
Having bought one of the uprated master cylinders from Midwest and been pleased with the improvement in pedal feel I thought I would retry a set of Wilwood 4 pots (the Midwest variety) , previously I found the pedal travel too much with the Wilwoods and so went back to standard calipers. I then thought that larger discs would be another upgrade. Having assembled the parts on a bench it appears that you can fit the Wilwood's plus 257mm Fiat discs (from a Tipo, but very common across the Fiat range) and get them under a 13" wheel. All that is required is a bracket to bridge the gap between the hub mounting holes and the caliper mounting holes, the difference unsurprisingly being being 30mm. Looking at the clearances I would think the standard caliper would also fit. with a suitable bracket
Hoping to road test it within a week or two and so will report how much of an improvement the set up gives.
 
Which arrangement did you end up with; stock diameter rotors or 257mm, and I assume the Wilwood calipers with the upgraded MWB master cylinder?
 
Nice set up. I want it. :D
It will be interesting to see how the up-rated master compares with the stock one when the Wilwoods are on.
I'm sure the 257mm rotors are solid (not vented)? Either way the increased diameter will be a benefit.
How did you make the new bracket to mount the calipers with the bigger rotors?
 
Every application is different but I had WHOA brakes on my spider and X and noticed no increase in pedal travel (this kit used Wilwood four piston calipers) I loved those brakes and that's with the stock rotors. Very modern feel to the brakes.
 
So is there a reason you would not use the 10.25 (260mm) vented rotors with the wilwoods? Also on the the master. I put in a new master when I did the brakes but not the Bayless one. But the brakes are sooooooo good. Pedal feel and travel is perfect. I had to dimple my front rotors myself and an run and aggressive pad. I also put some EBS yellowstuff pads on the back( they don't make a rear pad so I had to modify some fronts by adding a pin and shaving the surface down) on the back with EBS dimpled sloted rotos. Stainless steel lines on 4 corners.I really can't imagine a better brake feel? But if I am missing some room for improvement I am interested.
 
So is there a reason you would not use the 10.25 (260mm) vented rotors with the wilwoods?
Are those particular calipers wide enough for the thickness of a venter rotor? If not I'm sure there are other Wilwoods that are.
 
Are those particular calipers wide enough for the thickness of a venter rotor? If not I'm sure there are other Wilwoods that are.
Wilwood calipers just change the spacer plate between the two halves to allow for different rotor thicknesses. I am not sure what version this is refereeing to but I have put the Dynalites on a few cars and they are all this way. The good thing is that the 4 and 6 pots are interchangeable as far as the mounts go. Mine on the x have two spacer plates to fit the rotor. I have run this exact caliper up to a 13" rotor.

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Looks like they may be using the Wilwood Powerlite calipers. Still looks like those can take up to a .86 in rotor thickness so that would be vented.
 
Looks like they may be using the Wilwood Powerlite calipers. Still looks like those can take up to a .86 in rotor thickness so that would be vented.
The brake kits for the X that I'm aware of are the "Powerlite" version. But there may be other X kits using different versions.
 
There could be an issue using 13 inch wheels with Fiat 260mm rotors, especially if they are only 40mm high, compared to the older 157mm x 46mm high rotors. Vented rotors also push the caliper out even further laterally, they will probably foul on the inside of a 13 inch wheel.
 
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I have 257 x 20 vented discs with willwood dynalite calipers up front, no way to fit those under almost all 13" wheels as there is simply not enough clearance to the inside of the wheel, but with almost any 14 inch wheel there is loads of clearance. My cromodora daytona's fit, another set of campys I have fit, but most aluminium wheels with thicker castings may not have sufficient internal clearance

I use (a copy in steel) the whoa brackets for 257mm, and for the fatter vented disc just added a 4mm spacer in between the wheel flange and the underside of the disc where it mounts up, disc is perfectly central to the caliper. I run a croma / thema / early delta disc front, regata 100s 257 x 12 solid at the rear.

FYI Greg, Most willwoods will not pass safety tech for road use here in Australia, they don't have a dust seal in the caliper piston which makes them illegal for road use down under. Willwood do make aussie road legal calipers but you kinda had to ask for them special order last time I got a set, exactly the same dimensions, but machined to accept a dust boot . They are quite good value for money, with a good range of piston sizes.

For cheap and cheerful though, you simply will not beat upgrading to a set of regata 100s calipers and discs, fits straight up save for the internal thread pitch differences (1.0 thread pitch) for the hose fitting... but thats simply fixed with a 1.0 thread pitch banjo bolt) gives a 257 x 12 solid, bigger pad, sliding pin mounted caliper, completely road legal swap, no engineering required.

SteveC
 
For cheap and cheerful though, you simply will not beat upgrading to a set of regata 100s calipers and discs, fits straight up save for the internal thread pitch differences (1.0 thread pitch) for the hose fitting... but thats simply fixed with a 1.0 thread pitch banjo bolt) gives a 257 x 12 solid, bigger pad, sliding pin mounted caliper, completely road legal swap, no engineering required.
So what the hell is a Regata 100? Being facetious, but cars like that are not familiar to us due to never getting them here sadly. But seriously, what years were they commonly sold? I might be able to look up the parts from one of my European suppliers. Or better yet, happen to have the part numbers for those components?

And I might have got that reversed earlier about the Powerlite vs Dynalite Wilwood calipers in the popular X1/9 kits, sorry.
 
I have 257 x 20 vented discs with willwood dynalite calipers up front, no way to fit those under almost all 13" wheels as there is simply not enough clearance to the inside of the wheel, but with almost any 14 inch wheel there is loads of clearance. My cromodora daytona's fit, another set of campys I have fit, but most aluminium wheels with thicker castings may not have sufficient internal clearance

I use (a copy in steel) the whoa brackets for 257mm, and for the fatter vented disc just added a 4mm spacer in between the wheel flange and the underside of the disc where it mounts up, disc is perfectly central to the caliper. I run a croma / thema / early delta disc front, regata 100s 257 x 12 solid at the rear.

FYI Greg, Most willwoods will not pass safety tech for road use here in Australia, they don't have a dust seal in the caliper piston which makes them illegal for road use down under. Willwood do make aussie road legal calipers but you kinda had to ask for them special order last time I got a set, exactly the same dimensions, but machined to accept a dust boot . They are quite good value for money, with a good range of piston sizes.

For cheap and cheerful though, you simply will not beat upgrading to a set of regata 100s calipers and discs, fits straight up save for the internal thread pitch differences (1.0 thread pitch) for the hose fitting... but thats simply fixed with a 1.0 thread pitch banjo bolt) gives a 257 x 12 solid, bigger pad, sliding pin mounted caliper, completely road legal swap, no engineering required.

SteveC
Steve, just for interest sake, what calipers and brackets are you using at the rear with the 257mm solids? If I ever upgrade the fronts in diameter to say 240mm vented and the Wilwoods, which have a larger piston area also, I would want to upgrade the rears also for balance.
One downside of using Regata or many other non performance car calipers is the lack of availability of good performance/ racing brake pads.
 
regata / ritmo / strada, all the same platform / mechanicals (basically) they are a Fiat 138 chassis / model designation, available in sohc/dohc/OHC 1600,/diesel variants.

Certain models used 257mm solid discs up front, 100s regata (1600 dohc engine) ritmo 105 (a ritmo is basically a regata hatch if you like) ritmo 125 all used this same setup, pad is larger than the regualr "DB29 - which is the Bendix reference - seeing as they ae Bendix made brakes.... shape the usual Fiat uses.

Rear of the race car is 257 solid, willwoods (but much smaller piston) and uses the exact same adaptor bracket, just without the spacer under the disc hat. Brakes on the race car are like ths as it's being built to go lemons racing, and has to last 24 hours of abuse...

Greg, Hot setup for your road registered street car would be (and given the reduced weight of your car I would be hesitant to laod the car with very heavy discs that are unsprung weight)

257 x 12 discs up front, regata 100 calipers / carriers and pads of a decent compount, if you look around I think you'll find you can get right up to the equivalent of DS11 compound material

227 x 11 on the back, using 38mm piston rear calipers from 132/125, use a front caliper carrier (the cast iron bracket) from a regata 85s (manual), as this lets you use a larger pad shape (it's the same as lancia beta rear will work on the back)

much more consistant brakes, slightly more rear bias than stock.... cheap enough for the discs to replace them often if they ever get too hot, and very little increase in sprung weight mass

If you really wanted 257 solids on the back and you MUST have a hand brake, then you could use the 100s front calper CARRIERS that will bolt to the rear hub, and then use rear calipers from alfa 164 / fiat croma / lancia thema like one of these, they are 36mm piston (like a lancia beta rear, whuich will also fit an x19)

(https://www.ebay.it/itm/PINZA-FRENO...572419?hash=item35eadc4b43:g:lX8AAMXQsoNRhfu~)

240mm discs don't give much increase in the way of brake torque, the differnce in the radius centreline of the pads when mounted is so minimal... and if you're not complaining about fading and cooking the fronts, then going to vented discs is simply adding mass for no good reason. The 257mm discs howver ... well thats enough of a %age difference in the radius of the pad centreline , plus with the bigger pad....

wilwoods will have a bigger pad, but also more piston area, which equates to pedal travel issues with the stock master cylinder setup... I also run a willwood pedal box / and seperate circuit master cylinders which is bias adjustable on the fly.... but I don't have to pass any road legality engineering requirements, your car is road registered and it does.... every component would need to have engineering approval / certification.

Jeff, they fit virtually everything Fiat made 1985 - 1999 when fitted with engines over about 80hp, they kept the "usual" one piece sliding wedge design caliper for many smaller engined models ... but the larger cars got Girling brakes (most made under licence) for 48mm size the caliper is 791365 and 791366 , they also come as 52mm and 54mm and look pretty much the same.

791365 caliper.jpg


the reason that this is technically a far superior brake setup lies in the fact, and it is fact, that if you have the caliper fixed (in high performance situations) then usually you would set the disc up to be "floating" or self centering. The reason is "knock off" of the pads due to float / movement of the hub on it's bearings. Toodling around at pedestrian road speeds is hardly a test for brakes, and in that use, a fixed disc / fixed caliper could work perfectly adequately...but when pushed hard, the system will find it's limit

If the disc is fixed (i.e. bolted firm to the hub) then the calper is floating, i.e. able to self centre on the disc.

Look at almost every modern braking system and that's how it is.

Now the sliding wedge that Fiat used does a good job for it's cost, but it is right down at the economy end of the scale of what's available as production parts off the shelf, Fiat saved that for the low perfomance end of their range... the system would have been adequate, and in ways was ground breaking when introduced on the 1100 range back in 1966 on the 1100R, slightly upgraded and used on the Fiat 125 and Fiat 124 sedans in 1967/68... but again the biggest problem is actualy just simple deflection that makes the pedal feel soft / inadequate/ travel. To prove my point take a wheel off the car, have someone else press the brake pedal as hard as they can and watch how much the caliper "bends" in it's holder.

The Girling system with the sliding pins, simply has far less delection. The mount / pins / caliper body are all much later design, probably with a ton of CFA testing on computer, it works better and is simple to service, and has kind of become the industry standard as most "mid sized" cars are like this.

SteveC
 
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While it's great that Fiats had disc brakes back in the day, by today's standards sliding wedges are probably right up there with holding a wood stick against the wheels to slow them down. I got Prima brakes for the X an you can tell that the calipers are much more sensitive and engage the rotor in a nice sliding motion. I don't know what Fiat the Prima brakes are off of. At least those brakes do fit under 13" wheels.
 
I'm curious if Wilwood changed the design of their caliper to allow pads that better cover the rotor surface - I remember years ago looking at them for use on a Volvo - and the actual rotor surface coverage was not great. Have they fixed that? Also are the pistons progressive-sized in the 6 pots?

I went with CEIKA on mine (because of K-swap) - I've used them before, they hold up & pads cover the full depth of the rotor. Pistons are progressive staged. You can also spec SS pistons & full dust boots. For street use in NY, I wouldn't want anything less. 304mm rotors in my case, won't fit under less than 15" wheel with appropriate offset.

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