Brake upgrade options

ba3bas

Active member
Barnet
Hello

Thought I'd get people's thoughts on brake upgrades (beyond friction pads and good fluid)

I've spoken to a few members who have given some great advice using the M135i performance callipers and csl discs for the front.

The downside or concern for me is that upgrading the fronts only will or may mess with brake bias and that's not something I'd like to mess with.

I did think about getting the m135 rears which in theory should bolt on but not going to take a punt without some discussion.

It's been done but the amount of chopping of kit seems very hit and miss for there to be a balanced setup.

All in total cost would probably end up similar to D2 BBK with more tinkering.

Next step is a full BBK.

Someone on here had Alcons and I'd love to know where they got them from or the part numbers as I can't find anything.

D2 is an option
PB Brakes are another option.

Vmaxx I considered but have never done a specific kit for any z4
AP if I can get but rare enough and sell fast.
In any case, does anyone have any thoughts?

I know it sounds like I've come to my own conclusion but feel free to set me straight.

I'm trying to find the most cost effective upgrade to the brakes
 
BMW Performance calipers?

From memory people have made adapters to fit them to e46's. Can't see why they wouldn't fit our cars.
 
ba3bas said:
Hello

The downside or concern for me is that upgrading the fronts only will or may mess with brake bias and that's not something I'd like to mess with.

The z4 brake bias is front orientated. putting bigger brakes on the front won't change that. Lots of people drive around with a 135i brembo conversion with csl discs and stock in the rear. There is even 'bias'room in the rear to fit a more agressive pad.

I did think about getting the m135 rears which in theory should bolt on but not going to take a punt without some discussion.
Interesting. Do you know the dimensions of that disc, and particulary the hat depth?

I doubt it will be a straight swap, but it might be a candidate to get it fit with minimal tinkering.
I did mine a few years ago with a X3 rear disc conversion, but that requires lathe work etc, so that is not a diy job for most people.

I saw that the rear m135i disk is huge, so that might mess with the bias. The larger the disc, the more stopping power it has, as the caliper sits further from the center (moment of force: 8d92359cb96dd13783d854d68a3d48fd.png)

Regarding e46: the e46 is totally different on the rear brakes as the z4.
 
Well I've been offered a set of front and rear brembo for the m135i so I'd need discs for the front.

What size is the csl disc compared to the m3?

My thinking with the rear caliper is to just use the callipers on stock size rotors (m135i is 320)

I have no issue shaving bits off the discs with a lathe on the basis that's all I would be doing.

What size were the x3 discs?
 
I think the rear rotor is 345mm according to the bmw parts catalog.
The stock rear brakes are 294, so that difference is huge and maybe the caliper wont fully grab the disc.
Is the parking brake diameter the same? without that you'll fail MOT. Also the offset from the parking brake shoes can be a problem. on some bmw's they sit deeper in the hat.
Also the hat depth has to be the same as wel as the offset of the calipers.

The x3 discs are 320x22. The offset was about the same but I had to do some lathe work. I also had to make adapter rings on the lathe for the calipers (I use the e82 135i calipers front and rear)
I dont use a front CSL/z4m disc (345mm) but a slightly smaller disc (325mm), but from the same construction. That one bmw made as some sort of performance disc for the 330i. (was a kit from ecs)

Hasn't there already been someone here that made/tried to make a bbk from these calipers? Or was that on zpost?
I recall something like that.
Also with a kit like this
http://www.ebay.de/itm/BMW-M-F20-F22-F30-F34-F36-Kit-Bremsen-Bremssattel-Bremsscheibe-Bremsbelage-/231771731041
or this
http://www.ebay.de/itm/BMW-M1-M3-M4-komplette-Bremse-Bremssattel-Bremsscheibe-Bremsbelage-Sport-Brakes-/351642335829
 
I think ice seen the one on zpost using the stock m135 on the rear but the amount of machining and cutting of parts worries me.
Great work from what I saw but too much work negating any benefit.

I'm thinking using the X3 disc but depends what needs machining. Is it just the lip on the back to adjust the offset?

As for the fronts, apparently the 6pot brembo kit fits directly as long as you use 345mm disc.

Is that right?
 
ba3bas said:
I think ice seen the one on zpost using the stock m135 on the rear but the amount of machining and cutting of parts worries me.
Did they keep the handbrake? Zpost is full of yanks so no MOT there (most probably dont know the function of the handbrake :lol: )
You got a link to that install?

I'm thinking using the X3 disc but depends what needs machining. Is it just the lip on the back to adjust the offset?
The lip on the back needs to be machined off because it will get in contact with the control arm.
IT's the hat depth that has to be in the same kind of league as the one of the z4. Then you have to make adapter-rings to fine tune the position of the caliper. That only works if the mounting hole spacing on the new caliper is the same as the stock one. For the 135i caliper it is, but I dont know about the m135i caliper

As for the fronts, apparently the 6pot brembo kit fits directly as long as you use 345mm disc.

Is that right?
No it wont. You need to make a special bracket. (I assume you talk about the 135i (E82) brembo 6 pot)
 
You are right Guido

About front and rear and yes talking about the 6pots

Found the front and rear callipers (6pot front 2pot rear) for about 900 delivered.

Unfortunately the deeper I dig I can't help but feel that I should just save for a little longer and buy a dedicated set front and rear.
 
So you're not talking about m135i brakes (f20 1 series); those are 4 pot front, 2 pot rear), but about the 135i (e82 1 series) brakes; those are 6 pot front, 2 pot rear.

So what exactly is your plan?
 
Ok, so I've figured the front braking out.

The options are the 6 pot calliper from Brembo/BMW or a set of AP's which I can get to fit with a carrier and bracket conversion.

The rears are the problem.

I need to determine which discs from what BMW are a direct fit (just bigger than OEM - 295mm) for me to create a bracket to fit something like AP rear caliper or BMW 2 pot from the M135i.
It seems the issue is the parking brake fitment into the hat.

does anyone have a rear brake disc lying about they can measure to the point where a diagram can be drawn?
 
DPG said:
those D2's look quite decent.

There is of course a slight chance that a barely used set for a z4 might be coming up for sale in the near future..... :whistle:
In red.
 
I previously looked into Brake upgrades for my 2.0lt I sport, prices where coming in between £850 and £1800 for 4 and 6pot sets.

My main reason was for vanity/looks. I like the idea of having performance brakes, but realistically unless your on a track day, your never using there full potential. After lots of research I was aware that big expensive wouldn’t actually add much more stoping power. The standard BMW brakes work exceptionally well and are more than well up to the job, the only draw backs being the visual size and fading on track days.

A vast majority of braking performance is from the quality of tires and downforce.
If you had 2 identical cars on a runway traveling at 70mph, one with standard brakes, one with Big brake conversion. Get both cars to slam on the brakes to do a emergency stop side by side they will stop virtually side by side. Slamming on the brakes will cause lock up virtually instantly, causing the ABS to cut in and unlock the brakes. There is no advantage having bigger brakes here, unless you going to add massive amounts of extra grip and downforce.

Run the same 2 cars again but put the best tires you can buy on the standard brake set up and it will far outbreak the expensive brake upgraded car because of the grip.
Its not a case of how well and how much force a Brake produce but how much force can your car take? The bigger disk are only ever going to reach 20-30% of the actual performance.

That said for the last 3 years iv been running around with Brembo 325mm drilled disks on the front (bigger than 3.0lt Z4’s can fit with out the same modification). This is achieved by swapping the standard brake callipers for E46 330 D callipers. There are a few upgrades for the rears but the major issue is the Hand/Parking Brake not working.

To conclude, if you want to look good or you going get heavy track use, get a Big Brake conversion. They do work so much better at Fast Heat dispersal. If you want to increase braking performance upgrade your tires and fluid regularly, save a bit of cash and retro-fit BMW OME E46 parts.
 
ba3bas said:
You are right Guido

About front and rear and yes talking about the 6pots

Found the front and rear callipers (6pot front 2pot rear) for about 900 delivered.

Unfortunately the deeper I dig I can't help but feel that I should just save for a little longer and buy a dedicated set front and rear.

Do you have a link to these brakes you've found? Thinking of doing this exact same thing.
 
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