Z4m brakes.

[TomK]

Tom I didn't know that - so does that statement regarding the deployment of leading pistons on 4pot upwards calipers apply to all calipers or just specifically to the Porsche ones?

I've just got hold of a set of the bmw performance 6pots and csl discs to fit to my non-M Coupe, I was intending to leave the rears as they are certainly for the time being - curious as to your experience regarding biasing issues? I wouldn't have thought the bias would be significantly affected.

I certainly found the oe stuff doesn't hold up to track well last time out at Goodwood - the pads are totally shagged now, hence the look for a sensible upgrade!

Missed all the fun this morning
Ed, yes essentially the rear boxster calipers used in this application on our cars are mounted on the rear of the hub whereas in a boxster they are mounted on the front. These (and I believe most multi piston) calipers have different sized pistons front to back so that they apply different pressures over the pad, as the leading edge of the pads will tend to bite harder due to the inherent dynamic forces between pad & disc. The slightly smaller piston applies less pressure to the leading edge thus balancing the pressure over the pad.
Having it the wrong way round with the larger piston on the leading edge is probably not going to make a huge difference to braking capability but it will surely lead to uneven wear on pad. Fortunately the solution is very simple, just swap the link tube so that the bleed nipples sit at the top of the caliper. I'm sending my CV off to Red Bull asap :lol:
As for bias, there is a fairly simple calculation you can make to see what you're messing with, but no I doubt it's going to be a huge issue for you particularly as the bias in your case will be going towards the front. You could perhaps use a more aggressive pad compound in the rear to compensate if you feel the need.

 

[Beedub]

OP i have an off the shelf AP racing big break kit and apart from the insane replacement parts costs, including the consumables it really offers incredible brake behaviour.. really top notch pedal feel and modulation at the limit, and can take laps and laps of abuse. If it were me id consider a proper tried and tested setup, id always be wary pf something designed for another vehicle, however I'm aware some of these setups do function well also.

i noted on ZPOST that the m4 calipers bolt directly onto our hubs, no machining , no spacers or carriers needed, but id guess the piston size is not compatible with our vehicles.

 

[adam1985]

Tom I didn't know that - so does that statement regarding the deployment of leading pistons on 4pot upwards calipers apply to all calipers or just specifically to the Porsche ones?

I've just got hold of a set of the bmw performance 6pots and csl discs to fit to my non-M Coupe, I was intending to leave the rears as they are certainly for the time being - curious as to your experience regarding biasing issues? I wouldn't have thought the bias would be significantly affected.

I certainly found the oe stuff doesn't hold up to track well last time out at Goodwood - the pads are totally shagged now, hence the look for a sensible upgrade!

Missed all the fun this morning
Ed, yes essentially the rear boxster calipers used in this application on our cars are mounted on the rear of the hub whereas in a boxster they are mounted on the front. These (and I believe most multi piston) calipers have different sized pistons front to back so that they apply different pressures over the pad, as the leading edge of the pads will tend to bite harder due to the inherent dynamic forces between pad & disc. The slightly smaller piston applies less pressure to the leading edge thus balancing the pressure over the pad.
Having it the wrong way round with the larger piston on the leading edge is probably not going to make a huge difference to braking capability but it will surely lead to uneven wear on pad. Fortunately the solution is very simple, just swap the link tube so that the bleed nipples sit at the top of the caliper. I'm sending my CV off to Red Bull asap :lol:
As for bias, there is a fairly simple calculation you can make to see what you're messing with, but no I doubt it's going to be a huge issue for you particularly as the bias in your case will be going towards the front. You could perhaps use a more aggressive pad compound in the rear to compensate if you feel the need.

From my understanding the brake bias is not fixed and is automatically adjusted by the DSC so would this not compensate for the improved front braking?

 

[TomK]

From my understanding the brake bias is not fixed and is automatically adjusted by the DSC so would this not compensate for the improved front braking?

I think (but stand to be corrected) that the DSC module only adjusts bias when it detects a difference in deceleration of the wheels on each axle, i.e when a loss of traction (lock up) occurs. Up until that point the bias is pre set in the ecu to take account of the factory relative braking performance front to rear. If you alter this relationship with an upgraded front brake setup the car will still use the factory set bias up until the point of locking.

 

[adam1985]

I think (but stand to be corrected) that the DSC module only adjusts bias when it detects a difference in deceleration of the wheels on each axle, i.e when a loss of traction (lock up) occurs. Up until that point the bias is pre set in the ecu to take account of the factory relative braking performance front to rear. If you alter this relationship with an upgraded front brake setup the car will still use the factory set bias up until the point of locking.

You could be right, I havent managed to find any documantation about exactly how it works but I was under the impression, particularly from people discussing e46, that it is adjusted all the time to try and avoid lock up and the ABS kicking in. Found this statement on http://www.unixnerd.demon.co.uk/e46mechanics.html

Electronic Brake Proportioning (which I'm guessing comes out as EBV in German) adjusts the brake bias between the front and rear wheels under computer control. All cars have a bias that sends more braking force to the front wheels than the rear. The reason for this is that weight transfer under deceleration means the front wheels have more load on them and can thus sustain higher braking forces without skidding. It's often the case that the front wheels do two thirds of the work and rears a third, that's why front wheels get covered in brake dust more quickly.

EBV can adjust the front / rear bias to cater for a lightly or heavily loaded vehicle and thus optimise the overall braking effort and reducing the likelihood of the ABS kicking in. You often find a manual adjustable hydraulic bias valve in rally cars.

 

[Vanne]

OP i have an off the shelf AP racing big break kit and apart from the insane replacement parts costs, including the consumables it really offers incredible brake behaviour.. really top notch pedal feel and modulation at the limit, and can take laps and laps of abuse. If it were me id consider a proper tried and tested setup, id always be wary pf something designed for another vehicle, however I'm aware some of these setups do function well also.

i noted on ZPOST that the m4 calipers bolt directly onto our hubs, no machining , no spacers or carriers needed, but id guess the piston size is not compatible with our vehicles.

Gday Byron, I know it all the heat it may have gotten lost on everyone, I am not looking for a BBK, already have the Brembo GT's, do that's fine
I was just wondering what to do with my oem setup, and wondered if they would be a direct bolt on for non M zeds.. which isn't the case.thatnks heaps guys for all the inputs and advise.

Sorted.

Cheers. Byron, thx for the Mini review mate? Any issues? What pads are you running?

What pads are all you guys with BBK's running?

 

[MrPT]

I've just got hold of a set of the bmw performance 6pots and csl discs to fit to my non-M Coupe, I was intending to leave the rears as they are certainly for the time being - curious as to your experience regarding biasing issues? I wouldn't have thought the bias would be significantly affected.

The calipers are a good match for the non-M. Less than 5% increase in piston area vs stock. But you're also increasing the size of the front rotor by 20mm, so while it will be safe, you're not necessarily going to get the best total braking performance, front plus rear, and you might get the feeling of the car standing on its nose a bit under heavy braking (I haven't actually experienced this myself, but since you track your car you should be able to suss everything out quite quickly).

 

[Beedub]

OP i have an off the shelf AP racing big break kit and apart from the insane replacement parts costs, including the consumables it really offers incredible brake behaviour.. really top notch pedal feel and modulation at the limit, and can take laps and laps of abuse. If it were me id consider a proper tried and tested setup, id always be wary pf something designed for another vehicle, however I'm aware some of these setups do function well also.

i noted on ZPOST that the m4 calipers bolt directly onto our hubs, no machining , no spacers or carriers needed, but id guess the piston size is not compatible with our vehicles.

Gday Byron, I know it all the heat it may have gotten lost on everyone, I am not looking for a BBK, already have the Brembo GT's, do that's fine
I was just wondering what to do with my oem setup, and wondered if they would be a direct bolt on for non M zeds.. which isn't the case.thatnks heaps guys for all the inputs and advise.

Sorted.

Cheers. Byron, thx for the Mini review mate? Any issues? What pads are you running?

What pads are all you guys with BBK's running?

arhhh yes.... I've definitely got lost somewhere, i run APF404s for roaduse and pagids 29s for the track.... a set of pagids for these APs is like 700 quid plus !!!!

 

[TomK]

I was just wondering what to do with my oem setup, and wondered if they would be a direct bolt on for non M zeds.. which isn't the case.thatnks heaps guys for all the inputs and advise.

Sorry if the initial question got lost somewhere Vanne!
If it were me I would be selling the front caliper carriers and the rear calipers themselves to the m3 boys. Both are specific to the CSL upgrade a few do. The front calipers are exactly the same as a boggo m3, so not worth a lot. It's the front carriers, front discs and rear calipers (slightly increased piston size to work with the bigger front disc) that make up the difference between standard m3 and m3 csl/z4m.
The front carriers go for a fair chunk of money, £200 or so iirc

In answer to your other question, I use pagid rs-29 like beedub, an awesome pad if expensive. How you getting on with Brembo gt's? Taken it on track with them yet? What pads do you run in those?

 

[Anonymous]

So expert
Explain bleed nipples being at *top* of caliper and linkage at the base
As you'd have to be a kind of special to invert a caliper

As clearly shown here of passenger rear
But oh your an expert knowing which side of strut the springs are an all
Humble pie time

 

[TomK]

They look insane! Nice to see brembo logos on actual brembos for once too.

You remembered to swop the rear caliper bridge pipes/bleed valves round, right? Ok, just checking...

Haha hear you met Stu today

I had them painted and then remembered!
But size of pistons it's not an issue as only 2mm in it
Otherwise I'd have taken off to sort

And many thanks buddy
Not going for the plastic over brembo ebay specials

 

[TomK]

Sorry perhaps I wasn't obvious enough in my first post. Let me explain for you.
You swap the link pipe with the bleed nipples then use the left boxster caliper on the right hand side of the z4m and vice versa.
Bored of explaining this now to you. Go and read the multitude of guides on fitting your exact brake setup on the internet as I did when I fitted mine. Or get your F1 team to fit it.

eta: if you don't believe me, here's a random post on the internet I've just briefly searched for...

"Well I knew....because the rears on the Porsche are leading and on the M3 they are trailing...They have different sized pistions so to keep everything the same you have to turn them upside down....therefore you have to swap the connecting pipe with the bleed nipples. If you fit them as is they will have the pistions the wrong way round.

Some one else has done it wrong and got uneven pad wear, ie worn a set of pads out in 500miles (to the metal on one edge)"

 

[Anonymous]

But upon fitting can clearly see i was wrong as off car I made the mistake of thinking they had crossover pipe the wrong way round as it was ground up effort and had panicked thinking after all the effort and painting I had screwed it up with a school boy error

But I was wrong and can see are fitted and bled correctly and work properly with pistons in from small to larger
Of which can be seen from pictures

So I knew and looked at pics then you could've seen correct, rather than give verbal and incorrect abuse
But that appears to be your style
Act then think

 

[TomK]

oh right. That clears it up then

 

[Anonymous]

oh right. That clears it up then

Hahah
Well it was worth the banter anyways

Things off look different from those on and after his text saying had you swapped them panicked me!

By guy that prepped and painted them had already swapped the pipes over as going from front to rear of disc
Hahah.
Love life I guess

 

[mad4slalom]

Phew ! Thats sorted that out then

 

[bradz]

So I was just wondering.. my old Z4m stock brakes, will they fit on all Z4's? i.e. non M's or M's only? Its the claws, lines and discs.

another question i have is (as you guys are pretty close to the Oz inspection and no doubt the Oz inspections are derived from the UK ones somewhere along the lines in the past) for your MOT, do you guys have to get any certificate of install for your BBK? or you just bolt it on and off you go? as long as it passes the brake test, they don't look any further?

Cheers
V.

Just to throw this in...

You can use m3/z4M front calipers with an Si carrier with a 28mm 330mm m3 disc..

Adam

 

[Stu Boy]

20170430_104026.jpg

So I was just wondering.. my old Z4m stock brakes, will they fit on all Z4's? i.e. non M's or M's only? Its the claws, lines and discs.

another question i have is (as you guys are pretty close to the Oz inspection and no doubt the Oz inspections are derived from the UK ones somewhere along the lines in the past) for your MOT, do you guys have to get any certificate of install for your BBK? or you just bolt it on and off you go? as long as it passes the brake test, they don't look any further?

Cheers
V.

Just to throw this in...

You can use m3/z4M front calipers with an Si carrier with a 28mm 330mm m3 disc..

Adam

Nice one Adam and 345mm ///M discs also fit non ///M's with the 6 pot BMW Performance calipers too as I saw it with my own eyes on your Si, so I presume the standard ///M/CSL calipers and carriers will fit too.
Good to meet you at Zedfest

Pleased to see you have your new ride.

Stu

 

[bradz]

You have to use the Si carrier with the M3 caliper, the M3/CSL carrier the mounting lugs are too close to the back of the disc.

For those who haven seen its possible to fit them to a Si...

 

[Anonymous]

Nice work