Front Brakes to Rear - Will it work?

[bobswei]

I recently upgraded to front Wilwoods on the race car and now it's like there are no rear brakes. I have a pair of aluminum S calipers and wanted to put them on the rear (SC swing arms) but the bolt pattern is 3.5" and the swing arms are 3". Is there an easy solution to this? I saw one guy was going to notch the calipers bolt holes but I'm saving these for another car, down the road. Is a proportioning valve the answer? Are there adapters?
Thanks for any insight.

[gestalt1]

it really depends on the size of the pistons on the wilwood front calipers. you really want something close to a 1.6:1 ratio front to rear (assuming similar size pad area and rotor diameter). 4 piston, 44mm wilwood calipers have 3897 sq mm of total piston area (22*22*3.14*8) you would want 2435 sq mm (3897/1.6) total piston area for the rear. the front 48mm 2 piston calipers would have 2304 sq mm (24*24*3.14*4). this is in the ballpark. iron front calipers have 48mm pistons and 3" mounting so they can bolt on without adaptors. i think you will need a 23mm master cylinder for this setup. unless my math is completely off.
-matt

[Porsche Doc]

I have what you can use.
PM me.
Thanks

[Zeke]

Call Doc, but the center lines of the rotors are different with respect to the center of the caliper. He must have the adapter that you need.

[bobswei]

Thanks for the responses. I'm just heading out so will PM tonight.

Bob