AudiOn19s

8 total track days (5 at mid ohio, 3 at Putnam)
1500 street miles

All time on Hawk DTC-60 pads which are hard on rotors

cfjan

How much do the replacement rings cost?

F1CrazyDriver

Here are 2,000 kilometers added this past weekend of coast pure hwy 1 driving & twisty fun roads along the way. Brings me to a close to 10k miles on street plus those track days. IMO either the wrong stuff was ordered initially from the get go (rotor casting, thickness, vains, slots etc. / or their formula has changed.

Pads are pfc01s. Pretty harsh pads

pete95zhn

Hey, what's the height of the friction area of these rotors? Just got an idea of putting 15mm spacers between calipers and uprights and using 380mm discs with current calipers...

powdrhound

They are full depth 65mm rotors which accept the standard large pfc0991/pagid2707 standard pad shape. You CAN NOT use the regular 6pot calipers (normally used on 350 rotors) with the 380mm rotors due to the fact that those calipers will not space out radially because of their offset mount. As you try to add spacers, the bottom of the caliper will impact the larger rotor because the caliper moves away from the rotor at an angle as opposed to 90 degrees with respect to the centerline of the rotor. You must use the 380 caliper with the 380 rotors.

cfjan

Interesting, I always thought the calipers are radially mounted, that's why Alcon does 360mm rotor for the 996 GT2/3 to be used with 5mm spacers. Or it is that 5mm is not big enough difference compared to the 15mm?

powdrhound

That's exactly correct. 5mm is about as big of a spacer you can use before the bottom of the caliper would contact the rotor. Take a look at the mounting arrangement of the 6GT3 caliper vs. the radial mount 380 7GT3 caliper and you will understand what I'm talking about.

996GT3/997TT 350mm caliper (offset mount):

996 350mm GT3 calipers by pwdrhound1, on Flickr



997GT3 PCCB 380mm caliper (radial mount):

PCCB Right Caliper Rear View by pwdrhound1, on Flickr

993GT

996 GT 350mm caliper mounting...
Nice discs BTW, might be what I try next

cfjan

Got it. Thanks for the info. Guess 360mm rotor is the largest that can be used without going for a different caliper!

Does the 997 caliper have the same bolt spacing to be a direct bolt-on?

powdrhound

The 996 calipers have a 146mm bolt spacing. The 997 380 caliper has a 225mm bolt spacing. You must use the OEM Porsche/Brembo adapter to bolt the 380 caliper to the 996GT2/3/Cup upright. If doing the conversion, you would also need to install the larger 997 rear calipers to maintain the proper brake bias. The 996GT2/3 caliper is too small. Finally, you would need to install a 997GT3 brake master cylinder to firm up the pedal. A 997GT3 vacuum pump is a good addition to improve pedal feel (996 cars only use throttle body vacuum).

cello

Great thread and info all!

Explains a lot to me as I am just getting to know exactly what is on my car ....

Just re-checked per the posts below and in fact the rotors are 350mm so powdrhound's suspicions were correct and they are the OEM 996 rear calipers. In case anyone wants data for the shimming needed for 350mm rear rotors see below:

I just finished replacing all my wheel studs which necessitated getting to the hub. As a data point the shim length used on the rear calipers was exactly 11.85mm square (ie all four) and that puts the pad perfectly top/bottom of the rotor FWTW.

powdrhound

My guess is you have stock 996GT3 brakes as the 2405 pad is for the smaller 6gt3 rear calipers. The 1st gen 6gt3 used a 330 rear rotor and someone spaced out the caliper to use 350s. Demand makes a 1pc 350mm rotor for the fronts.

cello

You are correct; unfortunately tried to post from memory and do not have my info here to verify (hence the edit :-) ... Have the measurements and will double check when I get home. ... rechecked and revised post above ...

Thanks for the info!

v12man

The 380mm calliper has a different bolt space to the 350mm calliper - Porsche do have an adapter available that allows the swap to the 380mm calliper.

993GT

care to share the part number for adaptors?