Resized Rear Calipers?, techy help requested Options

[seanery]

I just pulled this from a page that redshift sent me to HERE. How is this done?
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The rear of the car received the following:

Widened stock calipers for use with vented rear rotors
Resized (smaller OD) 911 rear vented rotors (cross-drilled and slotted)

[brant]

1st... I want to say I agree with brad.
I sold my rear vented rotors and on the new car I will be running non-vented 914-6 rear rotors...

2nd, I've done the rear vented rotor twice... with 2 different ways. (Remember I sold both of them).

If you want to re-use a stock rear caliper:
you will need to buy original square O-rings (dealer type item) Also you will need all new hardware as in longer (vented) pad retainer pins, and springs. Also, the bolts that hold the caliper halfs together will need to be longer. I would suggest that you buy a complete core set of M-calipers in order to steal these bolts from. Finally, what I did was machine spacer blocks of the appropriate width from steel stock. After I had gotten them close, I took to a machine shop and had them surfaced and had the fluid passages cut. This is where the O-ring goes and there MUST be a square shoulder (like stock) inside of the passage for the square O-ring.

Next, buy 911 rear vented disks. They need to have the outside diameter turned down just a little bit for clearance. I sent my notes to the guy whom I sold mine to and don't have the exact figure any more. Just dry mount the calipers and you will be able to tell, Its not a lot, I think around 3/16. I had the same machine shop do the rotors.

My other set of vented rear used a 914 front caliper but spaced. For this application you do not need to make the spacing block from scratch and you can just use the spacing block out of the core M-calipers you buy. I was able to just leave the same rotors on the back... and do not know if you would have to turn them down this way.... This technique is easier but you do loose the parking brakes.

Warning.. this adds a lot of sprung weight.
I believe this would be appropriate for a high downforce, full slick car. I think it is actually detrimental to a small track car or combination DE/street car.

brant