944 calipers on 951 aluminum arms, which rotors?

[yetibone]

...just like the subject says.



Are there any Porsche rotors that have a lesser diameter, with the same hub depth? I have rebuilt some ATE single-pot rear calipers from a '84 944 N/A that I want to use on my 1303, and I have some '86 951 rear control arms already installed to the chassis. Are there rotors available that would make this work?

If not, will these calipers fit the narrower 931 aluminum arms? I am thinking the ATE calipers came on 931's, but I'm not positive.

[boygenius]

You should be able to use the N/A rotors for the year of your trailing arms. I thought you had the late aluminum arms. The 944 N/A has the same rear calipers for most of its production run. I think 83 through 89 are the same caliper. I have N/A calipers on my late 951 arms.

[yetibone]

I DO have late aluminum arms. Mine are exactly like the ones Zen is using on his '73, and should be like yours too. The rotors that came with those arms are too large for the N/A calipers.

What rotors are you using on yours? Do you have a part # handy?

[boygenius]

I thought that 1985.5 through 1986 was the early aluminum arms and 1987 and later were the later wider arms.
Here are my trailing arm numbers to see if they help clear up the trailing arm info.
Left part # 951.331.513.0 and 302.948.0.00701
Right part # 951.331.514.0 and 302.947.0.00701
It looks like they have both turbo and non turbo part #s on them.

There are no part #s left on the rotors if there were any to begin with. My suspension is all from a 1987 944-S. To the best of my knowledge there is NO difference in the brakes between the S and regular N/A. I often use www.pelicanparts.com to cross reference part #s to see what fits. When you go to buy rotors check out www.autohausaz.com, they have some good prices on german car parts.

Check this out.http://www.pelicanparts.com/catalog/...pg5.htm#item22

[zen]

according to the 944 manual i have:

924S, 944 and 944S had 282.5mm front and 289mm rear
944S2 had optional 304mm fronts and same rear
Turbos up to end of 1988 had 298mm front and 299mm rear.
as of MY88, 951s had 304mm front and 299 rear.

it doesn't list new thickness, but gives wear limits of:
924S, 944 and 944S - 19.1mm and 19.2mm
944S2 - 26.6mm and 22.6mm
Turbos up to end of 1988 - 26.6mm and 22.6mm
as of MY88, 951s - 30.6mm and 22.6mm

BG, you are right on your first statement. i am not sure on the NAs, but in 87, the 951s went to the late arms and the deeper hub depth for ABS option. all of the difference in track width is in the hub and rotor. i have a set of 87 and up rotors on mine and have a spare set of 86 rotors. i can take any measurements you need. let me know.

[yetibone]

SWEET, yours are the same part # as mine, 951.331.513.OR (514.OR on the right) so I CAN use *these arms* with ATE calipers :agree:

SOOO... I should be able to use 87+ 944S rotors which are a 10mm smaller outside diameter than the turbo rotors I have, and will fit the deeper Turbo hub.

Time to buy some rotors... Thanks for the help guys.

[boygenius]

Glad I was able to help. What type of rotors are you going to get, stock, slotted, or cross drilled.

[yetibone]

Originally Posted by boygenius

Glad I was able to help. What type of rotors are you going to get, stock, slotted, or cross drilled.

Stock. I doubt I'll ever get the brakes hot enough to distort stock rotors.

[boygenius]

Originally Posted by yetibone

Stock. I doubt I'll ever get the brakes hot enough to distort stock rotors.

Let me drive it and I'll have them glowing bright red.

Cross drilled look so much cooler though. :agree:

[yetibone]

Well, I just got my rear rotors, and they are even deeper than the 951 rotors I have.

Gonna send 'em back and see if '86 944S rotors are what I need...


EDIT>>> I fingered it out! I have EARLY ARMS! Mine have bumpstops and the later ones don't, apparently. I remembered the post from superman a couple of years ago about their differences, so I dug it up and sure enough that's where my goof came from.

Soooo...