930 rear caliper machining - dimensions?

[jpnovak]

Yes, I checked the archives. I find lots of references to the VCI site and I know what exactly needs to be machined. I just need the dimensions. This would be a good time to add the information to the archives. So...

Can anyone provide the specs for machining rear 930 calipers to use on 911 rear trailing arms. Its a no-brainer that the spacing of the new holes is 3" compared with the 930 trailing arm dimension of 3.5". From the pictures I have seen I calculate (infer) that the holes are moved inward 15mm on the center line between the mounting holes. Can anyone confirm this?

I also infer that the spacers are needed to bring the mounting flange on the trailing arm flush with the inside face of the caliper (pistons). Thickness of the spacers will depend on the depth of the plunge cut to prevent them from moving.

Thanks for any help you can provide.

[89911]

Call VCI, I'm sure they would be glad to send you the measurements You need to get one off the car for the correct sizes. I have them on mine, but don't plan on pulling them soon. That lower bolt is a problem to tighten. I have pictures of them before I installed them if you want. It should be enough to match up the landmarks to work. Let me know.

[jpnovak]

You are right. I am sure VCI would be happy to send them to me. Pictures would be great. The ones on the VCI site are not high enough resolution to blow up to take measurements off.

Anyone have a machined set on the bench that they could measure?

[911crazy]

Hi Just giving it a bump with the hope the Goran might be able to help with the measurements. As I am also about to fit turbo calipers to my 87 Targa and I live in South Africa. Freight would be a killer.

Thanks Craig

[beepbeep]

Is this good enough?

[beepbeep]

Otherwise I can ask Mattias if he remembers the dimensions. But it will have to wait after midsummer-festivities.

[911crazy]

Thanks that is a great help and if you get the chance to ask Mattis it would be really appreciated.


Cheers Craig

[jpnovak]

Goran, Thanks for the pictures. Here is what I get from your pic. It is nearly the same as I got from the VCI site.

There are two measurements in the picture. X is the distance between the original mounting holes, 3.5". Y is the offset of the new mounting holes.



X(mm) / 3.5 (in) = Z (mm/in) scale of picture.

Y (mm) / Z (mm/in) = offset of new hole (in)

offset of new hole (in) * 25.4 (mm/in) = metric conversion

When I print the picture and use a compass/caliper I get:

36.86mm/3.5" = 10.53 mm/in

[17.1mm offset/10.53 mm/in]*25.4 mm/in = 15.6mm offset.

So one result shows 15mm and one shows 15.6mm. I guess that 1/2 mm would not result in too much pad overhang.

Now to try the spacers...

[89911]

A few more pictures.