BMW M Performance BBK RETROFIT

[Daemonblitz]

For anyone who may have been wondering, this project came to a quick halt today after some test fitting.
In short, the hat of the new rotors is so deep that even without a dust shield the disc itself would make contact with the control arm/tie rod end. With different rotors I am convinced the kit would still work, but I am not really interested in going down that road.
This was definitely a learning experience for me, and I hope it helps anyone who may have been considering something like this.

[Beedub]

can you just shim the rotor hat out from behind ?

[Daemonblitz]

Originally Posted by Beedub

can you just shim the rotor hat out from behind ?

I had considered adding a spacer between the hub and the rotor, but it would have to be over an inch thick and it would just affect the front track too much for my liking, I'd have to get different size rims since I'm already maxed out on how much rim I can fit underneath the fenders.

[deemo319]

Originally Posted by Daemonblitz

Hello all,
I have an amazing opportunity to pull the trigger on an M Performance BBK originally designed for the new F series vehicles at a crazy price.

I am aware that these were not designed for our cars and that custom brackets will have to be made to get them to fit, however I am confident that I can get them to work.

All that aside, considering that these are not fully floating discs and not drilled (only dimpled), would anyone be able to chime in on whether this would be a significant upgrade from our stock setup.

I am interested to see what everyone's opinion is on this.

Specs are:
370x30mm and 345x24mm rotors with four piston front and two piston rear.

This is the kit in question below:
https://www.ecstuning.com/ES2587022/

That's actually a pretty damn good price for everything that comes with it.

[GuidoK]

Originally Posted by Daemonblitz

In short, the hat of the new rotors is so deep that even without a dust shield the disc itself would make contact with the control arm/tie rod end.

Have you test fitted the front caliper from that set on the stock disc?

[inTgr8r]

^ I agree, you need to work with the stock rotor and then get a bracket to fit the caliper.

[Daemonblitz]

Agreed, the calipers could have been made to fit on stock rotors but I did not want to run with those. And I didn't bother to test fit caliper only.

[GuidoK]

Shame really. I think the stock z4m discs might be even better than those mperformance discs. Although those mperformance discs are bigger. (z4m discs are floating, and the complete center is aluminium)

But the front calipers only have lugs, not a bracket, so it's very difficult to adapt/fit the calipers on a specific size disc. Normally you change both the offset and the distance from the axle with that bracket (make the bracket in a different size). Now it's not possible so you might be stuck on those disc sizes.

Did you take any pictures (or measured) how far the offset of those front discs was compared to the z4m discs?

[Daemonblitz]

Originally Posted by GuidoK

Shame really. I think the stock z4m discs might be even better than those mperformance discs. Although those mperformance discs are bigger. (z4m discs are floating, and the complete center is aluminium)

But the front calipers only have lugs, not a bracket, so it's very difficult to adapt/fit the calipers on a specific size disc. Normally you change both the offset and the distance from the axle with that bracket (make the bracket in a different size). Now it's not possible so you might be stuck on those disc sizes.

Did you take any pictures (or measured) how far the offset of those front discs was compared to the z4m discs?

the other discs were roughtly 1.5-2 inches closer in to the suspension than stock, huge difference.

[GuidoK]

That really is a big difference. So a very deep hat on the front.

What are you going to do next? Look for another bbk?

[Daemonblitz]

Originally Posted by GuidoK

That really is a big difference. So a very deep hat on the front.

What are you going to do next? Look for another bbk?

For now I have braided lines and Motul 600 brake fluid on order. Will see if I'm any happier with that on the stock rotors with PF-06 pads. If not will probably look for a used E46 M3 BBK, but that may not happen until next year.

[The Shoe]

Listen to the Hack about the piston surface area. Most people just don't seem to understand this.

[GuidoK]

Originally Posted by The Shoe

Most people just don't seem to understand this.

Developpers at AP seemed to have a different approach (and you'd figure they'd know what they'd be doing as they also develop F1 braking systems). See my previous post

Also it's not just piston surface area. In the end its
The piston surface area equals only one of these parameters
And the above equation doesnt really show the total braking force of the car (as most piston configurations will be easily stong enough to let the ABS kick in), but it is a factor in the predicted brake bias. And for most track conditions, the stock set brake bias could do with a bit of emphasis on the rear (so less on the front). It's set to the front because that gives a more safe/predictable feel in all conditions (so lockup always happens on the front tyres, no matter what the conditions), but it's not so good for the overall brake performance.
BMW's dont have automatic variable brake bias.

[Vanne]

agreed, those stock CSL floating rotors are pretty darn good, much, much better than most of the other crap running around, if you could fab a bracket to fit those callipers on the stock rotors, now THAT would be a cool project. But if you take into account the time and effort, not to mention the unknown your dealing with, your probably better off going with a set of known callipers from AP, Brembo or stop tech.

[3GFX]

Anyone tried these puppies yet?

Cheaper than a lot of big brake upgrades. Maybe not as good looking or as 'strong' of a caliper but still.

https://www.ecstuning.com/BMW-Z4-3.0...ing/ES2842149/