Feeler: Girodisc 2-piece floating rotors for E46 M3

[zivagolee]

Hi r4dr, I have this Essex rear kit which fits onto stock rear rotors (https://www.essexparts.com/ap-racing...kit-rear-e46m3). Would the girodisc setup work these calipers?

[r4dr]

Hi r4dr, I have this Essex rear kit which fits onto stock rear rotors (https://www.essexparts.com/ap-racing...kit-rear-e46m3). Would the girodisc setup work these calipers?

Pagid shows that pad to have a 48mm swept height. Are you running the kit now? Can you confirm if the outer edge of the pad is lined up with the outer diameter of the stock rotor?

[zivagolee]

Pagid shows that pad to have a 48mm swept height. Are you running the kit now? Can you confirm if the outer edge of the pad is lined up with the outer diameter of the stock rotor?

I'm using the Ferodo FRP201W pad as recommended by Essex. There's note at the bottom:

Again, please keep in mind that the above is not an exhaustive list, and that there are many other pad compounds available in this shape from other manufacturers. Please note however, that the pad shape we use in our caliper is available in a variety of radial depths (heights), and that Essex recommends the 48mm radial depth version for use with OE sized replacment discs. Other radial depths are available to use with aftermarket replacement 2-pc discs that have shallower depth faces. Please contact us for the appropriate pad depth if using aftermarket 2-pc discs.

I'll go take some pics of the rear later.

[r4dr]

Anything < 50mm pad height would work with the rear setup we want to do. We have pads we're targeting for the factory rear sliding caliper, the Porsche rear caliper that everyone swaps to, and based on what you've told me, that AP caliper.

[BigRussia]

Sorry, I meant to reply to your post but I kept getting pulled away. Did you happen to measure the GLOC pads for an actual thickness when new?

The GiroDisc rotors are specced to be the same thickness as the OEM CSL rotors (28mm when new). My 16mm pads were a tight fit in the caliper with new pads + rings, but I didn't have to force anything. If I remember correctly, I could rock the pads slightly which means there is probably around 1mm of play left.

I will say that sometimes pad manufacturers play fast and loose with the thickness spec versus what the pad is in real life. A lot of setups have some wiggle room, but if the setup is tight and the pad is just over the spec, you might have an issue. That could be why the titanium heatshields fit on half the pads.

My friend runs this setup on his Z4M track car based on my recommendation, and we saw a pretty noticeable improvement on pad wear and brake temps when he dumped the OE CSL rotors in favor of GiroDiscs. I can't emphasize how much a true 2-piece rotor and 50% more vanes help when it comes to brakes on these cars.

Unfortunately I did not measure the G-LOC pads when brand new But good to know the Girodisc rotors are the same spec thickness as the CSL ones! I dunno why I thought they were slightly thicker.

I have since ordered the Girodisc front rotors and new PFC08 pads in (supposed) 15mm thickness to run with them. I will try this new setup without the Ti heatshields first just to see how the Girodisc rotors and PFC pads perform as a baseline. With these same G-LOC pads and OE CSL rotors I am still having long soft brake pedal on track this weekend, even after having brake system professionally bled and flushed with new SRF by my indy shop.

Glad to hear about the cooling capabilities of the Girodiscs, I am really hoping my problem is a pad and rotors issue as at this point I've replaced everything else other than the master cylinder but my mechanic didnt believe it was bad and I dont have all the telltale symptoms of a bad master, he too recommended to change my pads and rotors from the current G-LOC and OE CSL Ive been running rather than throw money at a new master. I will followup once installed and got a track day on them (hopefully soon in Feb)!