F8X Brembo BBK Swap on E46 M3

[Epsilon]

Did you use hardware store bought bolts? I was under the impression caliper bolts are hardened and specially treated.

[Johnvu]

How does the brake bias change with these?

Front what I have read, If you have a newer ABS system (2003+), the bias is spot on, and the older M3's are slightly rear biased.

[SpaceJockey]

Nice write up! These look great. I wonder how weight compares to the Porsche/CSL combo. Interesting that BMW made the ///M logo read bottom to top, regardless of side. Would have been easier to just make all of the calipers the same. The driver's side orientation kind of bothers me.

[SpaceJockey]

So who is going to do the carbon ceramic write up?

[Johnvu]

Did you use hardware store bought bolts? I was under the impression caliper bolts are hardened and specially treated.

I used grade 10,9 bolts which are definitely up to the task. These were not at my local hardware store like Home Depot, instead I had to go to a specialty fastener store in Houston. I would have honestly rather used the factory style flanged bolts but I couldn't find them locally. I will likely order some and installed them when I go to swap the rotors around and install new pads. I don't think this is necessary, but more of an OCD thing LOL.

[Johnvu]

Nice write up! These look great. I wonder how weight compares to the Porsche/CSL combo. Interesting that BMW made the ///M logo read bottom to top, regardless of side. Would have been easier to just make all of the calipers the same. The driver's side orientation kind of bothers me.

100% agree with you here... Maybe I can install the logos rotated 90 degrees whenever I get them refinished. It won't be OEM but at least they will all be facing the same way lol.

[Johnvu]

So who is going to do the carbon ceramic write up?

LOL Ballers only DIY. I would definitely read that DIY and dream though. I would imagine the fronts would require the same 2.5mm shave down and the rears the same bracket and probably additional cutting.

[S14]

Nice write up! These look great. I wonder how weight compares to the Porsche/CSL combo. Interesting that BMW made the ///M logo read bottom to top, regardless of side. Would have been easier to just make all of the calipers the same. The driver's side orientation kind of bothers me.

I would guess these are significantly heavier just based on the larger diameter rotors and larger front calipers/pads.

Ok, I did little googling, I found this: https://f87.bimmerpost.com/forums/sh....php?t=1307736

M2 (same as M4 I believe):
-Front calipers: 10.78lbs
-Front rotors: 24.89lbs
-Rear calipers: 7.94
-Rear rotors: 20.39lbs

total: 64 lbs



996/M3 CSL brake kit:
-996 front calipers: 6.4lbs
-M3 CSL 345mm front rotors: 19.1lbs
-996 rear calipers: 5.2lbs
-M3 328mm rear rotors: 15.9 lbs

Total: 46.6lbs



So just off these rough numbers, the M4 brakes are 10lbs a corner heavier in the front and about 7 lbs heavier in the rear. No adapter brackets or pads are added into these weights, but I'd bet the large front calipers on the M4 have larger (heavier) pads as well.

[Tbonem3]

Those weights, at least for the 996s, are not fully correct. The rears are much lighter than the fronts.

[S14]

Those weights, at least for the 996s, are not fully correct. The rears are much lighter than the fronts.

I figured they were close, but not fully accurate, but 996 caliper weights are surprisingly hard to find on the internet. porsche 914/930 nerds (they are as nerdy as us) can tell you the clamping force, rotor weight centripetal force angle applicator etc, but hardly any weights on calipers!

Next time you have a set, could you weigh them?

[ATB88]

I figured they were close, but not fully accurate, but 996 caliper weights are surprisingly hard to find on the internet. porsche 914/930 nerds (they are as nerdy as us) can tell you the clamping force, rotor weight centripetal force angle applicator etc, but hardly any weights on calipers!

Next time you have a set, could you weigh them?

Just weighted mine, got 6.4 lbs front and 5.2 lbs rear. Without pads.

[S14]

Just weighted mine, got 6.4 lbs front and 5.2 lbs rear. Without pads.

awesome, ill update it!

[Tbonem3]

Thom, unless you drained them completely, I think there's some fluid in those that would affect the weight a little.

I'm surprised the delta isn't larger, probably because the fronts as so much larger it fools you into thinking it's more like 150-200% the weight of the rears.

[tedbm3]

Good write up , can’t wait to install my set

[r4dr]

Comparing weights without acknowledging the massive increase of rotor area is missing a huge part of the upgrade... the 996 upgrade is a lot of work only to just use stock ZCP-sized rotors. Going from 345mm diameter front rotors to 380mm (the F80 rotors) alone is a 20% increase in rotor area, not to mention pad size (no idea how this compares).

I'd pair these calipers with Girodisc 2-piece rotors (https://www.girodisc.com/Rotors_c_1592.html) if I were aiming to track this setup. Those F80 rotors are boat anchors.