Orientation of Performance Friction discs

[breeze]

Superb effort gents - just what I needed.

Despite gettign gutterly drenched in the rain discs and pads (RS29s) are on and bedding in nicely.

[Nords]

Originally Posted by northernjim

I know it was a bit misleading


what I mean is that the vanes inside the discs are there to cool the discs down, and that the airflow thru the vanes should go from the centre of the disc to the outside.... [ which is where you would fit any cooling ducts to the back of your discs]


ballcocks! AP will be better telling you than me- taken from there brake fitting guide -

AP Racing Formula Big Brake Kit Owner’s Manual
P14.070 / issue 1 Page 6 March 2004

DISC ROTATION DIRECTION

It is a popular misconception that the slots on the surface or drillings through a disc
determine the direction of rotation. In truth, for an internally vented disc, the geometry of the
vanes dictates the direction of rotation.

There are two types of ventilated disc design vane types in use:

n Straight

n Curved vane

The straight vane types are non-directional (identifiable because both discs will be listed

under the same part number), and hence can be used on either side of the vehicle.

The curved vane disc, however, is directional. A curved vane disc must be installed with the

vanes running back from the inside to outside diameters in the direction of rotation (see
the figure).
Orientating the disc in this manner creates a centrifugal pump. The rotation of the disc
causes air to be pumped from the centre of the disc, through the vanes, and out through the
outside diameter of the disc. This greatly enhances the disc’s ability to dissipate heat.
That is the important bit....

To aid cooling, some vehicle manufacturers include scoops to direct airflow to the disc

inner diameter. If desired, ducting can also be added to allow the disc to run at optimum

temperature, especially when the vehicle is used for circuit track day events.

http://www.apracing.com/drawings/for...it%20guide.pdf

page 6 of this guide shows this info and a good picture too that i couldn't copy....

Well it would be if AP discs weren't made out of cheese (early sets anyway!) This is a thread about Performance Friction discs, admitably with excellent AP calipers!

I tried a 997RS recently with std calipers and the ceramic discs. Although much better in terms of being progressive, I think my RS29 in AP Calipers as just as good, if not better!

[s.mac]

Ras did you tighten to a specific torque setting ?? if yes what was it

[shimmy]

Originally Posted by s.mac

Ras did you tighten to a specific torque setting ?? if yes what was it

the disc bolts are torqued i think to 14nm, hand tight virtually

[SpineOnABap]

Shimmy, you're not running Lo-Spec calipers are you?!

[shimmy]

Originally Posted by SpineOnABap

Shimmy, you're not running Lo-Spec calipers are you?!

i personally dont use my brakes, i just throw the car in sideways

but for you hobby drivers and car park cavaliers here is an M3 sheet from AP (the online one for 5575 cappilers doesnt show torque but it is the same for BOLT 10 - look at the table mid left)

http://www.apracing.com/drawings/p12116.pdf

[s.mac]

Thanks Shimmy

[DuncanR]

Hey T$, BET YOU WERE WASHING DOWN fAVA BEANS WITH THAT cHIANTI WERENT YA !!.... oh bollox.... not typing all that again

[breeze]

Originally Posted by shimmy

the disc bolts are torqued i think to 14nm, hand tight virtually

Yep as above - 14nm (10.5lb/ft or similar).

The bolts that came off were a lot tigher and had definitely been over tightened. A few snapped off.

Worth getting a spare set of AP bolts ahead of time if you have the chance...

[shimmy]

Originally Posted by breeze

Yep as above - 14nm (10.5lb/ft or similar).

The bolts that came off were a lot tigher and had definitely been over tightened. A few snapped off.

Worth getting a spare set of AP bolts ahead of time if you have the chance...

theya re lock nuts so you should replace all of them really (especially as they are brakes)

i have replaced mine 3 times and every time they are a few that break and a loads that are really tight but they all were originally only 14nm tight