Feeler: Girodisc 2-piece floating rotors for E46 M3

[elbert]

Finally had the chance to install my front Megane RS kit with the rotors and they fit like a glove. I'm still impressed by the bang for buck with the Freakyparts kit. Rears are next on my list!

If you find yourself short on time, I will begrudgingly accept a set of rear rotors and test them on my car. 😉

[r4dr]

NIce, can you share your impressions when compared to stock? I have 6-Pot E82 calipers and they are nice, but if I am honest they dont have as much bite. the calculator shows they have less clamping than OE, and it shows. I think these with the larger pots dont degrade clamping force. do you know the piston size?

I had a dinner to get to, so I’ve only driven it back across the shop. I believe the Megane calipers are 40/40 for piston sizes. I don’t remember how that stacks up to the stock sliders, but I remember doing the math and it seemed fine.

I will say that the pedal was plenty firm without much dead travel once the calipers were bled. I don’t know the piston sizes in those E82 calipers offhand, but they are not my favorite caliper design and the oddball pad shape is a drawback. If the clamp force numbers all check out, you might want to look at how much friction your pads are making.

[Bry5on]

We made some progress today. Thanks to rapid prototyping via 3D printing, I test fit a proof of concept cross-section to see how much room there would be with a Porsche caliper. Plenty of clearance. Note that this is with the D738 pad shape (much more common Cayman rear) versus the D737 shape (986 front) which people run to sweep the full E46 rear rotor.

For the fellas who want to keep the stock rear caliper, I double checked with PFC's current stock on their 7855 shape. This is the custom shorter pad they developed to run with their own 2-piece rear rotor. They have plenty available in race (including PFC11) and street Z-rated compounds.

With this setup, we should be able to run off the shelf pad shapes while retaining the factory e-brake.

Let us know if there’s anything we can do to help you with the rear project!

[r4dr]

Bimmerworld got me the PFC rear pads, I've just been out of town the past week or so. Hopefully I can test fit with the plastic cross-section piece next week.

[BigRussia]

Finally had the chance to install my front Megane RS kit with the rotors and they fit like a glove. I'm still impressed by the bang for buck with the Freakyparts kit. Rears are next on my list!

Nice, I’ve been following this thread as I’m planning to do the FreakyParts 345mm kit with Girodiscs as a track day upgrade (paired w 996 rears). Curious, what D1001 pads thickness did you use? Seems some brake pad manufacturers offer different thickness of the D1001, either 14.7mm or 16mm. I plan to run the 16mm (also seems more common option, from the 8J TTRS, Camaro SS and EVO X, while the thinner 14.7 is for the STi and hard to search for Astons) but want to make sure there wont be any fitment issues with the Girodisc 345mm rotors.

Here’s Ferodo’s info on their pad thickness offerings:

[Sharocks]

Are the curved slots available on the standard Brembo/Stoptech 355x32 replacements?

And what about the rear rotors in stock sizes for two piece?

My 17's won't clear a BBK in the rear lmao

[r4dr]

Nice, I’ve been following this thread as I’m planning to do the FreakyParts 345mm kit with Girodiscs as a track day upgrade (paired w 996 rears). Curious, what D1001 pads thickness did you use? Seems some brake pad manufacturers offer different thickness of the D1001, either 14.7mm or 16mm. I plan to run the 16mm (also seems more common option, from the 8J TTRS, Camaro SS and EVO X, while the thinner 14.7 is for the STi and hard to search for Astons) but want to make sure there wont be any fitment issues with the Girodisc 345mm rotors.

Here’s Ferodo’s info on their pad thickness offerings:

I'm running 16mm GiroDisc GP10 street pads, and they fit in there. The calipers seem set up to swallow up to a 30mm thick ring, so the 28mm factory-sized ring leaves another 1mm of wiggle room on top of that.

Some manufacturers make different versions, some just sell the same 15mm pad for all those applications.

Are the curved slots available on the standard Brembo/Stoptech 355x32 replacements?

And what about the rear rotors in stock sizes for two piece?

My 17's won't clear a BBK in the rear lmao

All GiroDisc rings (well, we still have some old stock that's slowly going away) are now curved slots. The rears are still on my to do list, but we got busy this summer with other projects. I have the 3D-printed cross-section to test fit on my car. I've already confirmed that we can run the D738 pad in the Porsche rear caliper with the rear rotor I have in mind, and I just need to confirm that the same is true with the stock caliper and the trimmed PFC pad shape.

[eacmen]

Are the curved slots available on the standard Brembo/Stoptech 355x32 replacements?

And what about the rear rotors in stock sizes for two piece?

My 17's won't clear a BBK in the rear lmao

Also would like to know if curved slots available for the stoptech 355x32 rings.

[Obioban]

I notice that ECS sells Girodisc rotors, and they qualify for they're newly announced lifetime warranty program:

https://www.ecstuning.com/b-girodisc-parts/girodisc-rear-2-piece-slotted-floating-rotors-pair/gir-a2-152~grd/

... consider me alerted!

[Sharocks]

I notice that ECS sells Girodisc rotors, and they qualify for they're newly announced lifetime warranty program:

https://www.ecstuning.com/b-girodisc-parts/girodisc-rear-2-piece-slotted-floating-rotors-pair/gir-a2-152~grd/

... consider me alerted!

Doing business with ECS is like doing business with Spirit Airlines.

[Projecte46m3]

Any updates on the matching rear rotors?

[Cronenberged]

Any updates on the matching rear rotors?

^^

[BigRussia]

I'm running 16mm GiroDisc GP10 street pads, and they fit in there. The calipers seem set up to swallow up to a 30mm thick ring, so the 28mm factory-sized ring leaves another 1mm of wiggle room on top of that.

Some manufacturers make different versions, some just sell the same 15mm pad for all those applications.

After installing the FreakyParts Megane BBK I put G-LOC 16mm D1001A pads for a track day with the new calipers. The pads were hard to get in, I had to push the pistons all the way into the bores just to get the pads into the caliper and this was with already slightly worn OEM CSL rotors (wasn't an issue with the 14.7mm Akebono street pads I installed before though). I couldn't even fit the .5mm Ti heatshields into the inboard side of the calipers, only outboard. After the track day, turned out the pads backing plates were right on touching the dust boots and melted them... not a big deal since I dont daily the car but was pretty bummer my new calipers already had their dust boots destroyed. See my post #12 in this thread for more details/pics
https://nam3forum.com/forums/forum/s...bbk-experience

So now I am looking to upgrade to the Girodisc front rotors, I am obviously not going to run 16mm pads again, but I am still concerned even with <15mm pads Ill still be having a hard time getting the pads in with the heatshields and if they'll end up against the dust boots again, since the Girodisc 345mm rotors are slightly thicker than the OEM CSL 345mm rotors?

[r4dr]

After installing the FreakyParts Megane BBK I put G-LOC 16mm D1001A pads for a track day with the new calipers. The pads were hard to get in, I had to push the pistons all the way into the bores just to get the pads into the caliper and this was with already slightly worn OEM CSL rotors (wasn't an issue with the 14.7mm Akebono street pads I installed before though). I couldn't even fit the .5mm Ti heatshields into the inboard side of the calipers, only outboard. After the track day, turned out the pads backing plates were right on touching the dust boots and melted them... not a big deal since I dont daily the car but was pretty bummer my new calipers already had their dust boots destroyed. See my post #12 in this thread for more details/pics
https://nam3forum.com/forums/forum/s...bbk-experience

So now I am looking to upgrade to the Girodisc front rotors, I am obviously not going to run 16mm pads again, but I am still concerned even with <15mm pads Ill still be having a hard time getting the pads in with the heatshields and if they'll end up against the dust boots again, since the Girodisc 345mm rotors are slightly thicker than the OEM CSL 345mm rotors?

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.

[r4dr]

Any updates on the matching rear rotors?

^^

I'm going to dig the short annulus PFC rear pads I bought and finalize the test fit. I know they're in my garage somewhere, and I'd like to get that wrapped up before things get crazy again this spring.