rbahr

Hi all,

Could someone please tell me what the dimensions of the front and rear 996 RSR brake rotors happens to be?

The 996 GT3 has 350 mm front and 330 mm rear

Does someone happen to know if the rear brake Caliper for the 996 RSR is equivalent to any street part?

Thanks

Ray

claykos

Front is 380 mm x 32 mm thick
Rear is 355 mm by 32 mm thick.

Calipers are brembo race parts that were not on any street car.

JoeMag

what the calipers look like....

http://www.ebay.com/itm/Porsche-996-...tr#ht_82wt_896

claykos

There's actually 2 versions - the cars came standard with 4 piston front and rear (similar looking gold brembo) all the way from 2000 GT3R to 2004 RSR. But many of the 04/05 RSRs were updated to the 6 pot endurance package like those pictured in the ebay ad. I think the 6 pot endurance package used a thicker rotor (although it may have just been thicker pads). Diameters were the same though.

rbahr

Thanks,

I have been trying to adapt the front and rear RSR uprights to my 04 GT3 - a street/track (mostly track) car. I have installed the E brake assembly now on to the calibers. I REALLY didn't want to spend $5K on calipers and then $$$ on rotors/pads etc, in addition to what was already spent.

Does anyone know what the 6GT3RS used for rear calipers?

Thanks

Ray

claykos

You are going to have much more trouble with the front than the rear. I believe the rear caliper bolt spacing is the same as on a cup car (or street gt3). It's setup for a bigger rotor, but the actual bolt pattern on the caliper studs is not unusual. The front RSR uprights have a super wide caliper bolt spacing for real racing calipers. It's something like a 10 inch spread. There aren't any street calipers that have that kind of spacing.

Frankly, you'd be better off selling the RSR uprights and buying 997 cup stuff. The geometry is almost the same, but they have a much narrower caliper bolt spacing on the front upright. the 997 cups still uses a 380mm front and 350 mm rear rotor, but you'll be able to find those calipers and parts a lot more reasonably than RSR stuff. The 997 cup caliper *may* (i don't know for sure about this) be the same as a 997 gt3 street caliper (at least physical dimension wise).

rbahr

The fronts fit fine - I have the 6GT3RS uprights - pretty much the same as the RSR, but 6GT3 brake calipers, ABS, etc fit, and I get that pesky roll center, bump steer address AND a bigger/better wheel bearing...

I will be fitting the front rotors today, and I will see what that looks like...

As I understand it, there was a 997 GT3 that had front and rear rotors @ 350mm.

I would assume that changing master cylinder and any other brake biasing bit should allow me to run that setup? Thoughts?

When I get off my lap top and fix my machine (I hate Win 7), I will start a write up with pictures...

(This is the kind of thing that happens when an obsessive engineer has to many tools and feels obligated to use them )

Ray

JoeMag

Interesting on the change 4 piston to 6. Thought the 4 was just on the GT3R. Here's what the 4-piston's look like. Love that they take they hold 1" pads, last forever.

Rah996

I have a 2002 996 turbo... any idea how much a replacing the front brake pads should cost me?

rbahr

Joe: this is the 996 GT3RS street car (Euro only), so they had already got the bigger calipers...

Rah996 - not sure that this would be they best place for those type of maintenance questions - try the 996 turbo forums https://rennlist.com/forums/996-turbo-forum-61/

, but to answer your question - depends on the types of brake pads you use and if you do the work yourself or not...

Ray

claykos

From your post it sounded like you had front and rear rsr uprights. 996 RS street car front uprights are a good alternative. These are essentially the same as 997 cup (or 996 rsr with different caliper spacing).

If you are handy on a lathe I would think you could just shorten the caliper spacers on the rear to run a smaller rotor, or run a 350 mm rear rotor. I don't think the bias will be too much of an issue with 350 front and rear. Just run a less agressive pad in the rear. Assuming, you're sticking with the street GT3 power/ABS brake setup?

rbahr

Claycos:

I do have both a lathe and mill available - I updated the rear uprights to support E-Brakes ( Car may see a bit of road travel) already which required some milling...

I will indeed keep the GT3 ABS system, and will likely up the rotor size to 355mm - I think I would need to remove more metal that I want from the uprights, to stay with the 330mm rotor - still need to verify...

Not sure, but I think I would have preferred the GT3 RS rear parts as well...


Anyway from the various catalogs:
2004 RSR

Brake System
The GT3 RSR is fitted with a dual circuit brake system incorporating separate brake master cylinders. The front to rear brake balance ratio is adjusted by rotating the brake balance **** mounted on the dashboard.
Attention: Turning the adjuster **** allows the incremental adjustment of the brake bias to either the front or rear of the car. Changing the brake bias affects the handling characteristics of the car; therefore only small incremental adjustments (e.g. a quarter of one turn) should be made.
Brake system components
Front
Disc 380 mm diameter x 32 mm, ventilated steel disc mounted to aluminium disc bell.
Caliper Four-piston: 2 x 36 mm diameter and 2 x 44 mm diameter
Pad Pagid RS 19 (yellow), 26.5 mm thick.
Cooling Air intake with air distributor mounted to upright.
Rear
Disc 355 mm diameter x 32 mm, ventilated steel disc mounted to aluminium disc bell.
Caliper Four-piston: 2 x 28 mm diameter and 2 x 36 mm diameter
Pad Pagid RS 19 (yellow), 26.5 mm thick.
Brake pedal and push-rod adjustment
The brake pedal has no form of mechanical stop limiting movement in either the fore or aft direction. When the brake pedal is in the normal driving position (the brake pedal should be free of pressure – failure to respect this will result in faulty push rod adjustment) and the push rod correctly adjusted the free play of the push rod in the brake cylinder is correct.
Adjusting the push rod at the joint, changes the position of the brake pedal. Therefore, the brake light switch adjustment should be checked. The brake light switch should be adjusted to ensure that with 6 - 8 mm of pedal travel the switch is closed (brake light glows).
Setting brake pressure distribution.
A 17.8 mm diameter brake master cylinder is used for both front and rear brake circuits.
The following pressure distribution is achieved in the basic position: Front axle 50 bar, rear axle 55 bar.
Direction of rotation of the balance bar adjuster:
Anticlockwise front axle
Clockwise rear axle
The basic setting is adjusted as follows:
• Rotate the adjusting **** clockwise (rear axle) to the stop.
• Rotate the **** 7 complete revolutions in the anticlockwise direction.
This setting corresponds with the above mentioned pressure
distribution. Check using manometers to ensure that the
pressure is correct.

2005 Cup
Front brakes
Brake disc Diameter= 350 mm, one-piece steel
Brake disc thickness 33 mm
Brake pad 18 mm thick, colour green (Pagid P50)
Brake caliper 6 piston, aluminium brake caliper with
zircon oxide inserts, coloured red.
Rear brakes
Brake disc Diameter= 330 mm, one-piece steel
Brake disc thickness 28 mm
Brake pad 18 mm thick, colour green (Pagid RS14)
Brake caliper 4 piston, aluminium brake caliper with
zircon oxide inserts, coloured red.
Hand brake Not applicable.