rx7 caliper width and compatible Porsche rotors?

[pribs67]

I'm looking to do a big brake upgrade along with an IRS conversion. I'd like to use RX-7 calipers as they seem to be highly rated and quite a bit cheaper than the Porsche calipers and will, in addition, fit under my 15" Fuchs. Does anyone know of a Porsche rotor that will be compatible with the RX-7 calipers, or a source for blank rotors that I could have drilled to work with a Porsche hub? According to the Brembo site, minimum width on the rotors is 20mm. Thanks.

[flat]

Pribs67,

It doesn't really work out. The rx7 rotors (2nd/3rd gen) are 22mm new and wear limit of 20mm. The 944Na's are 20.4mm new and wear limit of 19.1mm. So if you use the rx7 calipers on the 944NA rotors you are overextending the pistons in the bores. I wouldn't do it. It might be alright when your pads are new, but as they wear you'd always (at least I would) overextending the pistons. Life is complicated enough, I don't want to worry about more things especially when it's related to the braking system of a vehicle that directly relates to the safety of myself, my passengers and others on the road.

Guys are selling kits with that combo, but looks kinda shady to me. Well, you have the numbers, you can decide.

There isn't any other rotor in the same neighbourhood, most P-car rotors are 24,28 or 32mm wide.

Easy,
Lanner

[pribs67]

Thanks Lanner, that's roughly what I came up with with research on the Brembo site. Would it be possible to fabricate 2 0.8mm shims to place between the pistons and pads? Or, as an alternative, could I use Porsche hubs with RX7 rotors machined to match? Thanks.

[rip]

how about spacers?

I don't know the offset of the fuchs, but if you will need to use spacers, why not use all mazda parts then get a spacer made that converts the 5x114.3 to the 5x130 bolt pattern?

Rip

[flat]

Pribs67,

I think the shims are a little shady, I wouldn't bother.

What bolt pattern are you trying to run? Porsche I guess. I can machine the rx7 rotors for the porsche pattern and with the rx7 billet hubs machined to the 5-130mm bolt pattern you'd be set. The only problem with this road is that next time you have to replace the rotors you'd have to get them machined. I can make up a jig so that you could drill the rotors on a drill press. (The rotor hole is just clearance for the stud).

Lanner