M5 M6 brakes on Z4 --conversion?

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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M5 M6 brakes on Z4 --conversion?

Post by Valor1 » Sat Feb 09, 2019 8:19 pm

One of the problems with a big brake kit on the Z4 is the rear electronic E brake.

the M5 / M6 factory brakes are nice, with six piston front calipers and they both use electronic brakes. Has anyone tried adapting an M5 / M6 brake set up to the z4?

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M5 M6 brakes on Z4 --conversion?

Post by Nictrix » Sat Feb 09, 2019 8:28 pm

Are the rear brakes the same setup as the Z?
I have an electronic handbrake on the X6 but it operates differently from the Z.
The X6 e-brake operates brake shoes and not the pads like the Z.
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M5 M6 brakes on Z4 --conversion?

Post by Valor1 » Sat Feb 09, 2019 9:06 pm

Nictrix wrote:
Sat Feb 09, 2019 8:28 pm
Are the rear brakes the same setup as the Z?
I have an electronic handbrake on the X6 but it operates differently from the Z.
The X6 e-brake operates brake shoes and not the pads like the Z.
Looks like the pads to me. Here is an M5 / M6 rear brake caliper
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M5 M6 brakes on Z4 --conversion?

Post by Valor1 » Sat Feb 09, 2019 9:09 pm

And here is a Z4 rear caliper.....looks the same :)))
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M5 M6 brakes on Z4 --conversion?

Post by Nictrix » Sun Feb 10, 2019 12:30 am

In which case if the calipers are the same there is no need to touch the rears at all.
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M5 M6 brakes on Z4 --conversion?

Post by Valor1 » Sun Feb 10, 2019 6:34 pm

Nictrix wrote:
Sun Feb 10, 2019 12:30 am
In which case if the calipers are the same there is no need to touch the rears at all.
Sorry, but that make no sense. Sdrive 35i Z4 rear brakes are 324 mm whereas M5/M6 brakes are 394 mm, nearly 20 percent larger and feature an aluminum bell. Braking is largely about leverage. Bigger disc yields greater braking leverage. Larger disc also absorbs more heat. The aluminum bell helps offset weight of a larger disc. Front discs are 399 mm whereas Z4 discs are on the 35i are 348 mm, 13 percent larger.....and six piston aluminum calipers. These brakes stop the 4300 pound M5 in the same distance as a Z4 that weighs nearly 1,000 pounds less. Just imagine the braking capability of these brakes on a Z4.

In addition, the reviews I've read show brake fade an issue on the Z4 and I have experienced this as well when running hard through canyons. I doubt there would be any fade with the M5/M6 brakes on a Z4.
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M5 M6 brakes on Z4 --conversion?

Post by Smartbear » Sun Feb 10, 2019 6:40 pm

Is there really much improvement to be had? After all the z4 brakes are powerful enough to activate the abs in the dry, so how much more braking force can be practically used?
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M5 M6 brakes on Z4 --conversion?

Post by Nictrix » Sun Feb 10, 2019 6:46 pm

Sorry I thought you were talking about doing this from an aesthetic point of view and changing the calipers for better looking ones.
There are lots of options for the fronts but not a lot for the rears thats why I was saying there was no need to touch the rears if it was just for looks.
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M5 M6 brakes on Z4 --conversion?

Post by GuidoK » Sun Feb 10, 2019 6:53 pm

Smartbear wrote:
Sun Feb 10, 2019 6:40 pm
Is there really much improvement to be had? After all the z4 brakes are powerful enough to activate the abs in the dry, so how much more braking force can be practically used?
Rob
I don't think braking force applied once is the main issue, but its all about stamina. Braking full on repeatedly every 400 yards on a track for an hour for example. Or going down a steep alpine pass at ridiculous speeds :wink:

But as long as I've not once read about rotor hat offset or caliper offset, I give this very very little chance of success :roll:

The rear M5 caliper is still a clunky steel single piston one though I think :?
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M5 M6 brakes on Z4 --conversion?

Post by Smartbear » Sun Feb 10, 2019 7:12 pm

GuidoK wrote:
Sun Feb 10, 2019 6:53 pm
Smartbear wrote:
Sun Feb 10, 2019 6:40 pm
Is there really much improvement to be had? After all the z4 brakes are powerful enough to activate the abs in the dry, so how much more braking force can be practically used?
Rob
I don't think braking force applied once is the main issue, but its all about stamina. Braking full on repeatedly every 400 yards on a track for an hour for example. Or going down a steep alpine pass at ridiculous speeds :wink:

But as long as I've not once read about rotor hat offset or caliper offset, I give this very very little chance of success :roll:

The rear M5 caliper is still a clunky steel single piston one though I think :?
Agreed on the suitability for track use, for the road though i think it’s 90% cosmetic and you just wouldn’t be able to realise any potential benefit.
Probably better to just change the fluid more often and fit some high performance pads?
Rob
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M5 M6 brakes on Z4 --conversion?

Post by GuidoK » Sun Feb 10, 2019 7:19 pm

It all depends on how you drive on the road. :rofl:
I mean on the autobahn speeds in excess of 170mph aren't strange. Having to brake really hard from those speeds also puts some real heat into your brakes. Same goes for that steep mountain pass if you do that at high speed.
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M5 M6 brakes on Z4 --conversion?

Post by Valor1 » Sun Feb 10, 2019 8:41 pm

GuidoK wrote:
Sun Feb 10, 2019 7:19 pm
It all depends on how you drive on the road. :rofl:
I mean on the autobahn speeds in excess of 170mph aren't strange. Having to brake really hard from those speeds also puts some real heat into your brakes. Same goes for that steep mountain pass if you do that at high speed.
In the process of setting the car up for 500 bhp. I've done BBK upgrades to two of my Ferraris, cars that already had four wheel, four piston Brembo brakes, and I can tell you as a matter of fact the bigger brakes make a dramatic difference and on my Z8 going from floater calipers to fixed Brembos was an even greater improvement, in braking and in brake feel.

It's unfortunate BMW cheaped out with the set up on these cars. Too bad BMW did not put fixed aluminum four or six piston calipers on these cars from the beginning. These brakes did not help the negative reviews of the E89.

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M5 M6 brakes on Z4 --conversion?

Post by SteveSmith » Sun Feb 10, 2019 10:14 pm

Smartbear wrote:
Sun Feb 10, 2019 7:12 pm
GuidoK wrote:
Sun Feb 10, 2019 6:53 pm
Smartbear wrote:
Sun Feb 10, 2019 6:40 pm
Is there really much improvement to be had? After all the z4 brakes are powerful enough to activate the abs in the dry, so how much more braking force can be practically used?
Rob
I don't think braking force applied once is the main issue, but its all about stamina. Braking full on repeatedly every 400 yards on a track for an hour for example. Or going down a steep alpine pass at ridiculous speeds :wink:

But as long as I've not once read about rotor hat offset or caliper offset, I give this very very little chance of success :roll:

The rear M5 caliper is still a clunky steel single piston one though I think :?
Agreed on the suitability for track use, for the road though i think it’s 90% cosmetic and you just wouldn’t be able to realise any potential benefit.
Probably better to just change the fluid more often and fit some high performance pads?
Rob
100% correct Rob, aesthetics :thumbsup:
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M5 M6 brakes on Z4 --conversion?

Post by Valor1 » Sun Feb 10, 2019 11:20 pm

Back to the original point of this thread:

Has anyone here tried adapting an M5 / M6 brake set up to the z4?

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M5 M6 brakes on Z4 --conversion?

Post by SteveSmith » Sun Feb 10, 2019 11:29 pm

I doubt it
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