Cracked AP disc :( => solution :)

[jpeeters]

Makes sense, Deluge told me that I'd be better off running something softer and less grabby at the rear to increase stability when standing on it. I'm running the standard CSL set up with braided lines and DOT 5.1 and they need an overhaul. Horrible pads on the street on my set up. Fab on track, but just noisy as hell off it! Can't be arsed blowing 5K on a A&P BBK though, its seems like overkill aside the huge callipers issue that will retain even more heat and I wondering how far I can upgrade the standard system...

The concern I have with upgrading the OEM setup is the responsiveness of the brake system. A 1-piston setup can never have the same bite nor be as precise as a 2 or more piston setup. Stopping power with Pagid RS14/RS29 is excellent (and with the right brake fluid they almost never fade), but it cannot match the modulation and bite of a BBK imho.

 

[Franzino]

The RS 29 pads tend to be superior to the RS19's in my opinion. As for the comments about them squeaking, my experience of them on both the CSL and a 996 GT2, indicated that it's only the rears that squeak, this as they rarely get up to their correct operating temperature and thus begin to glaze up.

Correct; if we are talking about initial bite, then RS29 is better then RS19. But they are not 100% my taste. I want really aggresive brakes, when you touch them there is a massive bite and hard braking from the beginning..so my choice is RS14 and I love them.

 

[Franzino]

I find having 29s all round (on an AP kit) means the rear is over-braked, so I have switched the rear pads to RS4-2.

Correct! The AP kit is rather big on the back of the Z4M...for this reason I was advised by Pagid and Simpson Motorsport to use RS4-4 as a rear pad.. In combination with the RS14 at the front, the brake balance is realy nice. I can brake later and harder than most Porsche boys...or I have more guts or confidence in doing so. Still, with this set-up the brakes are awesome and I never regretted spending that amount of money on brakes. It's not cheap and I thought long about this, before making the investment. The plan was to do a lot of trackday/year and keep the car for a long time...then it makes sense. The little money I saved in trying to upgrade the OEM brakes, is money that I used for AP brakes. The Pagid brake pads last longer with the AP discs and the AP discs last longer then the OEM discs (with track use). A full AP BBK is maybe to much... In my opinion you are almost at the same level with only a front AP kit... Put some RS14 in the front and RS29 (or RS14) at the rear and IMO brake balance will be fine.

 

[Franzino]

The concern I have with upgrading the OEM setup is the responsiveness of the brake system. A 1-piston setup can never have the same bite nor be as precise as a 2 or more piston setup. Stopping power with Pagid RS14/RS29 is excellent (and with the right brake fluid they almost never fade), but it cannot match the modulation and bite of a BBK imho.

For trackday use, more aggressive pads are required, such as Pagid RS29 to withstand the high temperatures that will be reached by the pads and discs on track. This is where the BMW single piston caliper design starts to fall apart, and you discover why BMW fit soft pads in the first place – the reason is that the swinging caliper is not very rigid or progressive in nature, meaning that there is no finesse in the braking. Outright stopping power with a track pad such as the Pagid is excellent, almost as good as an AP kit, but there is no finesse. You are either flat-out braking or not braking at all. Techniques such as trail-braking into corners are impossible. The aggressive pad solution is ideal if all you are going to do is 1 or 2 trackdays a year.

 

[ChawenHalo]

I wondering how far I can upgrade the standard system...

Brake cooling: http://www.z4-forum.com/forum/viewtopic.php?f=24&t=38775

Solid brake bushes: http://www.z4-forum.com/forum/viewtopic.php?f=24&t=45293

Nice one, does it improve response and feel? That's the one thing I really like about the OEM set up: the brakes have fantastic feel and are easy to modulate and the ABS never does intervene too early.

Dumm question, with the Goodridge installation, do the braided lines run through the whole system?

Can further improvements be made elsewhere on the OEM system such as master cylinder?

 

[exdos]

Nice one, does it improve response and feel? That's the one thing I really like about the OEM set up: the brakes have fantastic feel and are easy to modulate and the ABS never does intervene too early.

Dumm question, with the Goodridge installation, do the braided lines run through the whole system?

Can further improvements be made elsewhere on the OEM system such as master cylinder?

I have the solid bushes all-round on my Z3MC and just at the front on my Z4MC. They definitely improve the feel under my right foot because the calipers cannot twist, as they can do with the OEM flexible bushes, so the brake pads are always parallel to the discs, thus performing optimally.

The Goodridge braided hoses only replace the flexible brake hoses which attach to the calipers: the remainder of the brake line system is metal pipework all the way back to the master cylinder.

There's nothing wrong with the stopping power of the Z4M's OEM braking system, it's only the potential problem of duty cycle of repeated maximum braking events which might ultimately lead to brake-fade due to overheating on track. Brake cooling ducts address this problem.