Also, your post rang a bell with me. I went rummaging on another forum and found this thought I had from a year ago when I had time to contemplate such things and do the maths and research to make sure it was a sound idea:
I've been mulling over the 500's front brakes. I'd like them to be:
- slightly bigger
- much lighter
- 4 pot calipers that take a variety of easy change pads (yellows for track, etc)
- fit under 15" alloys because I love the way she handles on 15"s
To start the process off I bought a 500 1.4 front axle/hub/brake/upright assembly from Lewey so I wouldn't have to pull Isabella to bits measuring stuff up. After much procrastination and more thinking and measuring I think I can get away with 10.5 inch disc rotors like these:
That's 267mm in new world measurements which is 10mm bigger than the standard discs. These bolt on to these ally bells:
This solves a couple of problems, slightly bigger brakes so more efficient, yet at the same time they're a lot lighter than the standard cast discs due to the alloy bells in the middle. Offsets are variable. Just need to pick the right one or blanks that suit and do a lot of machining.
For the calipers I'm looking at Wilwood midilites. They're aluminium 4 pot calipers, very light and good for cars up to 1300kgs in weight. The body of the caliper is reasonably small and the range of pads is awesome. Everything from EBC and Hawk and Ferodo is made for these and quite cheaply. Also the pad change is as simple as pull a W bracket out by hand and pop the old pads out and new ones in.
I've measured the surface area of the standard caliper with the pi x r squared formula and then trawled the range to find a midilite that's got marginally bigger surface area than the standard caliper (taking into account the multiple pistons vs single in the standard). This should be an ideal fit, given that the standard master cylinder will cope with 20% increase before the pedal feel is affected according to Fiat.
Interestingly the surface area of this 4 pot is marginally bigger than the Brembo GT kit advertised for the 500/Abarth 500. Also, interesting side note, the master cylinder for both 500 and Abarth 500 are the same.
Then machine some brackets from blanks which are surprisingly cheap. My initial thought is to convert the measurements into an mdf template then take it to a mates garage and borrow his milling machine to mill them out of some alloy blocks. I haven't done this bit because work has been a nightmare. But for giggles, here's a progress shot from a bracket I'm making for something else:
Once I've got it all together I'll need new stainless flexi lines made, Fiat 500 at one end and wilwood fitment at the other which isn't that expensive. Then fit them, flush through with new fluid and test.
As regards cost:
To give you an idea of costs:
2 x Calipers = £279
2 x brackets = £30 (ally blanks)
2 x Ally bells = £120
2 x disc rotors = £120
2 x brake hoses = £50
Pads = £65
================
Parts Total = £664
That's before we take into account:
- Machining the 4x98 and centre bore into the ally bells
- Machining the brackets
- Brake fluid
- Bolts and washers
- Labour to install it
So realistically, some faffing about and about a grand. But you'd get a very nice setup that would fit under 15" wheels such as the pro race 2's I'm running on Isabella now.
Definitely a good idea, but you could still go bigger. Subaru get 294mm brakes under 15" wheels for their group N cars
Piccy of a very rusty 294mm disc of mine inside a 15" wheel
