Which porsche brakes fit on the z4m?

[ShawnPaul]

I have seen people convert their Z4M to porsche 911 brakes. Anyone have any details which ones work and what adapters I need? I heard the stock rotors work, but they require cayman pads I think. But this is all from conversation long ago and I can't clearly remember.

[rockstar93]

Brembo calipers from a 996 non-Turbo or a 986 Boxster S or Cayman S. Porsche has many Brembo calipers from different cars (in several different colours) so it's best to verify by P/N.

Part Numbers:

996.351.425 (driver side front)
996.351.426 (passenger side front)
996.352.421 (driver side rear)
996.352.422 (passenger side rear)

Additionally you'll need adapter brackets for the front and rear and brake lines. Rally Road offers all of this.

You'll also need to machine 5.5mm off of the base of the front calipers to fit the Z4M/CSL rotors.

As for pads, you would use the Porsche pads for these calipers, but for the rears you will have a rust ring as it doesn't have full coverage of the rotor so I believe some adapters allow for a 986 Boxster/Cayman non-S front pad to be used that remedies this.

I bought a set of calipers a couple years ago but haven't gotten around to refinishing or mounting them yet. A few users have this setup (some local to us).

[F360C]

Originally Posted by rockstar93

As for pads, you would use the Porsche pads for these calipers, but for the rears you will have a rust ring as it doesn't have full coverage of the rotor so I believe some adapters allow for a 986 Boxster/Cayman non-S front pad to be used that remedies this.

.

Just use Non-S Boxster front pads in the rear Boxster S calipers and no rust ring. Also by using this pad set up you get close to if not exact CSL brake bias % (IIRC).

All the parts needed for the conversion can be bought from RallyRoad.net minus the calipers/pads.

[jns_e85]

If one chooses to go the 996 conversion route, is there any benefit, besides cost savings, to only go 996 front calipers (or any BBK upgrade for that matter) opposed to front and rear?

I assume it would shift some of the bias to the rear, but in theory, would that assist with some of the hard braking squirmy booty shake the z4m gets on track? I believe I have read that some will run different pad compounds front and rear to essentially get the same effect to tame the rear.

[3002 tii]

Originally Posted by rockstar93

Brembo calipers from a 996 non-Turbo or a 986 Boxster S or Cayman S. Porsche has many Brembo calipers from different cars (in several different colours) so it's best to verify by P/N.

Part Numbers:

996.351.425 (driver side front)
996.351.426 (passenger side front)
996.352.421 (driver side rear)
996.352.422 (passenger side rear)

Additionally you'll need adapter brackets for the front and rear and brake lines. Rally Road offers all of this.

You'll also need to machine 5.5mm off of the base of the front calipers to fit the Z4M/CSL rotors.

As for pads, you would use the Porsche pads for these calipers, but for the rears you will have a rust ring as it doesn't have full coverage of the rotor so I believe some adapters allow for a 986 Boxster/Cayman non-S front pad to be used that remedies this.

I bought a set of calipers a couple years ago but haven't gotten around to refinishing or mounting them yet. A few users have this setup (some local to us).

All good info above. And if you buy brackets from RR, he will machine the calipers for you at discount so may as well purchase from him.

[Azeka1]

According to the extensive data found in buildjurnal.com (see below), the boxster S calipers (F&R) will yield an identical bias to oem ZCP/CSL/Z4M brakes.

However, I have yet to find data or real world examples of this caliper upgrade being faster and/or more reliable on track compared to a properly updated oem system (ss lines, track pads, 600* fluid and cooling).

In my opinion, it’s a pure cosmetic modification.

[3002 tii]

Originally Posted by Azeka1

According to the extensive data found in buildjurnal.com (see below), the boxster S calipers (F&R) will yield an identical bias to oem ZCP/CSL/Z4M brakes.

However, I have yet to find data or real world examples of this caliper upgrade being faster and/or more reliable on track compared to a properly updated oem system (ss lines, track pads, 600* fluid and cooling).

In my opinion, it’s a pure cosmetic modification.

Are you assuming it’s cosmetic because the rotors are the same? What about weight savings and increased pad area?

[Azeka1]

Originally Posted by 3002 tii

Are you assuming it’s cosmetic because the rotors are the same? What about weight savings and increased pad area?

Perhaps there is some weight savings but I have yet to see a Z4M or E46 M3 with this mod put down a faster time than a properly setup OEM system.

Using the M3 forums track times as a reference, I can't seem to find a time with this upgrade that hasn't been beat by an OEM setup. http://www.m3forum.net/m3forum/showthread.php?t=608703

[F360C]

Originally Posted by 3002 tii

Are you assuming it’s cosmetic because the rotors are the same? What about weight savings and increased pad area?

I have run both a mostly fully prepped stock set up (PFC pads, brass caliper bushings, high temp fluid, racing brake rotors and lines... just missing cooling) and now run the 996 set up. Here are the advantages I see to the 996 set up:

Modulation- so much better then the stock brakes. So much more feel and depth to the pedal. This alone I think makes me faster. That said I dont have any before and after data to back it up so it could maybe just be the extra confidence in the pedal giving me the illusion of being faster. I was never unhappy with the power of prepped stock set up but i always thought the pedal lacked feel compared to other cars I have driven. It's when you're braking deep in a corner and your at the last 10-15% of pedal pressure that I think the feel with this set up is most improved.

Pads swaps- the 996 set up is dumb easy to swap pads on. You only pull one pin and the pads are out.

Weight savings- You save about 2-3 pounds per corner.

I put my kit together for around $1200 including pads and for that cheap price i see it as a decent upgrade. Of course a PFC, Alcon or Stoptech setup would definitely out perform it but depending on what you're looking for in a brake set up it might be one that fits your needs.

[JimsR]

I have an e36 with the Porshe calipers and csl rotos, it was a great upgrade but i think at best they are on par with my stock z4m. Still would like a nicer looking caliper on the z4m though.

[3002 tii]

Originally Posted by JimsR

I have an e36 with the Porshe calipers and csl rotos, it was a great upgrade but i think at best they are on par with my stock z4m. Still would like a nicer looking caliper on the z4m though.

Is that your experience based on a road course or street/auto-x?

[JimsR]

^^^Opinion based on street driving. Thanks for clarifying.

[3002 tii]

Originally Posted by JimsR

^^^Opinion based on street driving. Thanks for clarifying.

Yea I don’t think anyone finds the factory brakes lacking for street so you shouldn’t feel a difference if you’re running same pads.

[jns_e85]

Has anyone who has done this conversion come from a straight oem setup or a slightly modified one with brass caliper bushings and a lot better fluid like Castrol SRF?

For me, brake pedal feel (read: inconsistent pedal) is whats lacking on track. If braking power is the same or close to OEM brakes, but a firmer and more consistent pedal feel is the result this mod, it may be worth it for me. However, if the same result could be achieved with bushings/fluid at A LOT cheaper cost, why not go that route?

[3002 tii]

Originally Posted by jns_e85

Has anyone who has done this conversion come from a straight oem setup or a slightly modified one with brass caliper bushings and a lot better fluid like Castrol SRF?

For me, brake pedal feel (read: inconsistent pedal) is whats lacking on track. If braking power is the same or close to OEM brakes, but a firmer and more consistent pedal feel is the result this mod, it may be worth it for me. However, if the same result could be achieved with bushings/fluid at A LOT cheaper cost, why not go that route?

I’ll report back in few weeks. I ran the stock setup with Castrol SRF and PFC (01 front 08 rear) and thought it was still underwhelming. Just waiting for weather to warm up so I can respray the calipers first.

[maupineda]

I know there is a lot of polemic about using the 6-pot Brembos from the e82 135i, but everyone who has done it speaks very well of them, particularly in the feel area and for street use (which is my case).

I already have a brand new BMW Performance calliper and I am at the edge of buying the other side to do this mod. I have to say I hate the mushy feel and long pedal travel of the stock brakes, coming from a Mustang with 6-Pot Brembos I must say the feel of the Z4M brakes is very poor.

So, for me going to the 135i BMW Performance option will be cheap as the callipers retail for 450 new, plus the Epytec brackets, so ~650 in total to go this route.

[Terraphantm]

Originally Posted by Azeka1

According to the extensive data found in buildjurnal.com (see below), the boxster S calipers (F&R) will yield an identical bias to oem ZCP/CSL/Z4M brakes.

However, I have yet to find data or real world examples of this caliper upgrade being faster and/or more reliable on track compared to a properly updated oem system (ss lines, track pads, 600* fluid and cooling).

In my opinion, it’s a pure cosmetic modification.

Just FYI, but those tables are inaccurate. They assume that the master cylinder results in different front and rear pressures, which is not actually the case.

The relative differences should be accurate, but the actual numbers are wrong.

[thielepr]

Any spacers needed with the Porsche brakes?

[gnx]

I've had my car 13 years now and thought that it's about time to look into possible upgrades, so i pulled the trigger and bought me some used brake calipers.

I took them to a local brembo specialist to start with machining the front calipers.

He is not happy with what he saw in the pics from rallyroad.net that i had with me. He is concerned with the structural integrity.

Has anybody had any sort of issues with material degradation or anything?

[Vanne]

I havent heard of anyone with dramas from the RR adaptors, that said, i dont run them.
Not really why i responded to this thread, but there you go, the real reason ive responded is the that someone mentioned mushey and long travel oem brakes?

Mushy? probably means you got air in your system?

I ran the Oem setup with proper pads and lines and fluid for over 2 seasons on track and i must say, these are really good for an OEM setup. ive never had mushy brakes and i cant breally comment on the /long/ travel, as that would depend on what your used to. I have had brake fade a few times, but thats only because of my dumb driving style and no brake cooling.

at any rate, id say the OEM setup on the M are pretty darn good. That said, there is a huge difference with swapping to a propper setup BBK. I dont think i ever out drove the OEM setup, aside from my own stupid mistakes and driving style. My current setup just allows me /more/ stupid mistakes without having to come in. (i am still learning , trying to make a few less stupid mistakes)

(the real issue with brakes on track is the pre-emergency stop pressurising the brake line when you come quickly off full throttle - thats caught me a few times)

[gnx]

Can someone who has the porsche calipers on confirm that spacers are needed either up front or in the back as well, and if yes which ones?

I am on 235/35/19 up front, 265/30/19 in the back. Offsets 35 front, 30 back.

[JimBob0047]

Rally Road also has this. Anyone have any experience with these?