E89 Z4 4-corner big brake upgrade with Brembo m-sport calipers

[billj457]

Great thread! If you happen to still have your stock 325M wheels, do they fit in front with the 370mm setup?

Just to follow up, I had some brake maintenance to do on my e90 335 and while the calipers/rotors were off, I mocked up the S2NHA caliper and tried to install one of my e89's 325M wheels. Bad news is they don't fit, they might fit if you remove the little pad weights, though. Good news is that my 335's 18" Apex EC7's fit.. Time to start saving for another set of EC7's!

 

[Mittu]

Still not happy with it. Mid-soft pedal feel on first push, hard on second. I did a power bleed twice. I've done one manual bleed. ISTA vibrate on all. I'm going to do another manual bleed (person pressing pedal).

I've heard from a number of people running bigger brakes setups that the stock booster works fine. So I don't think it is a booster size issue (and Z4 booster is unique ... at least I've not found a swap). I think this is a pesky Ex bleed issue.

When I did my X5 big brake upgrade, had issues bleeding that too. Power bleed is just a non starter on a brake caliper change. But I digress.

Fantastic Thread; read every word of it at least 3 times.
Its 2023 and you're still the only maverick to retrofit M callipers to the rear.

I'm in the UK and used parts are readily available at reasonable prices over here.

I really REALLY want to do this upgrade. You've inspired me!... but I lack any experience or knowhow on machining things.

Is there any chance I could buy a set of the rear calliper brackets and hub spacers from you?
I have a US address it can be sent to.

P.S. did you resolve the soft pedal issue?

 

[fmorelli]

Fantastic Thread; read every word of it at least 3 times.
Its 2023 and you're still the only maverick to retrofit M callipers to the rear.

I'm in the UK and used parts are readily available at reasonable prices over here.

I really REALLY want to do this upgrade. You've inspired me!... but I lack any experience or knowhow on machining things.

Is there any chance I could buy a set of the rear calliper brackets and hub spacers from you?
I have a US address it can be sent to.

P.S. did you resolve the soft pedal issue?

THanks for the kind words. You are in the UK ... the upgrade for you is PB Brakes. They have a great setup for the E89 Z4!

 

[Armando1969]

Fantastic Thread; read every word of it at least 3 times.
Its 2023 and you're still the only maverick to retrofit M callipers to the rear.

I'm in the UK and used parts are readily available at reasonable prices over here.

I really REALLY want to do this upgrade. You've inspired me!... but I lack any experience or knowhow on machining things.

Is there any chance I could buy a set of the rear calliper brackets and hub spacers from you?
I have a US address it can be sent to.

P.S. did you resolve the soft pedal issue?

I second What Fmorelli said, I have the rear big brake set from PB on my car myself. Great company to do business with and their product is very good.

 

[Armando1969]

Would love rear PB brake kit, but its over £2000!
Ive already installed M callipers on the front. Just trying to figure out how to instal the rear set.

Rear discs for a range rover IV are within spec for the G30 M calliper. No alterations would be needed to calliper or brake pads.
Relatively cheap, only 50 quid starting price and readily available everywhere.
Rotors, callipers and pads tallying up to less than £500.
Just need calliper carrier brackets making... I'll knock on a few doors locally.

In the UK, German cars are by far the most common. Blink and you'll miss a dozen go by. Used parts are very affordable and easy to obtain.
But even then, the e89 is an uncommon car. I drive 2hrs in traffic everyday, and I probably only see 1 a week. There's more Bentleys than e89s', and rarely is it a 35is.

Hi Mittu,
I understand you reasons and reasoning, but I question that when you do the total cost calculation at the end, that it was cheaper. I hoop for you it will be, but reading Fmorelli's story I doubt it.
Enjoy your car
Gr Armando,

 

[fmorelli]

Hi Mittu,
I understand you reasons and reasoning, but I question that when you do the total cost calculation at the end, that it was cheaper. I hoop for you it will be, but reading Fmorelli's story I doubt it.
Enjoy your car
Gr Armando,

@Mittu tagging you as well.

The above comment is on point, in my view. It is not as simple as making a bracket, either. There was custom fitting work that was done to make it all happen. The goal was to solve the problem for my car, not to solve the issue as one would with a product. It was quite a bit of work, as well.

I would seriously suggest the PB route, unless others are now making electrohydraulic brake solutions for later model cars. It's not cheap, but my solution was hardly cheap in any dimension. I had my reasons for doing it this way, and doubt anyone factor that into their build. In my case, I wanted a factory look. Kind of ridiculous, I know, which is why I would not recommend it. Best of luck to you!

 

[Krampus]

Not all images are displayed. What was done at the machine shop?

 

[Mittu]

Adaptor for caliper carrier.

 

[pbondar]

Please see my thread on E89 rear BBK Mk II here..

Its a rear big brake kit Jim, but not as you know it! - Z4-forum.com

 

[pbondar]

Reference my low cost rear big brake upgrade..

Trying to get pad alignment on the discs perfect..getting hard work cutting these brackets out in steel so went for 3D printing purely for alignment purposes…

So the good news is that the 345mm version is now perfect with the pad sat nicely on the disc using all the pad and most of the disc..previously the top of the pad was just fractionally past the top flat part of the disc..

The 370mm version needs one more iteration as the front of the pad is siting fractionally lower than the rear..2mm adjustment on the front caliper bracket hole should see it..

Then ready to hand them over to the laser / water cutter buys to fab a few..

Interesting to see how much disc the original 300mm rear disc pad missed..

 

[wheela]

Reference my low cost rear big brake upgrade..

Trying to get pad alignment on the discs perfect..getting hard work cutting these brackets out in steel so went for 3D printing purely for alignment purposes…

So the good news is that the 345mm version is now perfect with the pad sat nicely on the disc using all the pad and most of the disc..previously the top of the pad was just fractionally past the top flat part of the disc..

The 370mm version needs one more iteration as the front of the pad is siting fractionally lower than the rear..2mm adjustment on the front caliper bracket hole should see it..

Then ready to hand them over to the laser / water cutter buys to fab a few..

Interesting to see how much disc the original 300mm rear disc pad missed..

Cool! I'll be looking at 3D printing some parts for my build. What material and print technology did you use?

 

[pbondar]

Cool! I'll be looking at 3D printing some parts for my build. What material and print technology did you use?

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The brackets are incredibly light …I felt they’d crumble when the bolts were tightened but I applied about 5nm-7nm of torque to the bolts with no issues..

Wouldn’t trust it for real from 175mph…

 

[pbondar]

One of the things I’ve always disliked with E89 rear calipers is the unfinished look caused by them using a casting process using steel…this ends up with a pebble dash look that no amount of paint hides..-plus the remnants of the cast flash lines etc..

I bought a pair of F series M5 rear calipers for developmental purposes for my rear E89 big brake kit..

I discovered that the caliper itself (not the carrier) is in fact the same as the F series 5 50i caliper I’m using for production of the BBKs.

So I decided to refurbish these and re-use them.

I’ve never liked the blue that is now so popular on BMW calipers ..

So..a belt sander, conventional sander, flap wheel in the 4.5 angle grinder and a dremel later..

Voila..polished caliper ready (subject to final finish) for treating and spraying in your preferred colour..

Pics show blue and silver calipers pre process and calipers on their way to final polish before painting..

 

[pbondar]

Previously I’d discussed the evolution of various BBKs for E89s…

Of course there are several manufacturers and suppliers that will do bespoke BBKs for the front of E89s..it’s relatively simple for the fronts as essentially the E89 has the same fundamental front end design as non M E90s and E82s..give or take some offset/king pin issues..

So Alcon, AP racing and Brembo all do BBKs..around £3,000 upwards ..

Also Ceika and Performance Brakes in Taiwan and HK do pretty ones too..again same prices for decent multi pot bigger brakes..

My and others search has been about exploiting off the shelf products from BMW and their suppliers ..

Many folks even some E89s have gone down the route of F series M cars with 4 pot Brembo attached to 340/70/380 mm BMW discs..

My example in gold with a 340mm caliper upgraded to support a M2/M4 380mm disc..(caliper is the same for all disc sizes..just the mounting bracket size changes)

However..whilst I’m playing and following on from my success with creating 345mm and 370mm rear BBKs for the E89..s much tougher challenge due to the unique rear brake system of the E89 with integrated electronic parking brake..I couldn’t resist this next challenge.

And so..here is the next project..the Brembo BIG BBK using 2017-2023 Shelby Mustang Brembo made calipers sold and used by Ford on the 526-650 BHP versions..

The reason for this..apart from..because you can is..

These calipers..made by Brembo retail through the Ford dealer network for around 375 dollars ..but..you can get them discounted to around 250 USD..ironically the bright red ones are a few dollars cheaper than the matt grey version..red was for the the 350 GT the grey for the 350..

These are a monobloc design ie cast in one piece which makes it more difficult/ expensive to machine than a two part design as used on the M Performance /M2/M4 calipers..go figure..

For the E89 this is married to the same M2/M4 380mm diss but with a lot more pad and clamping force..

A US company has made an adapter bracket which I’ve imported..

However there are some issues to resolve..

First is front / rear bias..

So my BBK calculator..(others are available)..allows one to model the impact of various front / rear brake setups on the front / rear bias..

This BIG Ford based Brembo kit pushes the bias forward a lot in the absence of an E89 rear BBK..

However ..the B21 370mm rear E89 BBK brings the bias into the range between the 35is and the other E89s ..ie normal..

Second issue is master cylinder ..size ie bore diameter and leverage on the pedal..

This is an imponderable at this stage..

Some people…almost all in the US have tried this on E90s..some report some ‘soft’ peddle issues..

Others no issues..

Complicating matters there are two electronic options..

The E90/E89 has an option in the Vehicle Order to code ‘SPBR’..BMWs then 6 pot Brembo…however this boy is a bit bigger all round …

Secondly ISTA offers DSC recalibration..where the DSC recalibrates its management of the calipers pads by analysing the current forces acting on the discs / pads and recalibrating its system to ‘optimise’ response..

Frankly until it’s all bolted up..programmed and tested..who knows..

You’ll be relieved that I’ll be refinishing the Brembo in a touching Phoenix Gold….

Pics show a rear caliper of a F series about the same size as an E89 front caliper ..plus the 340/370/380 BMW/Brembo front caliper and the FoMoCo/Brembo Shelby Mustang front caliper plus their associated pads..

Enjoy!