Z4M brake conversion on 3.0si?

[bmwaddict]

A mate of mine will have a full set of oem Z4M brakes (calipers, pads, discs) for sale soon and I wondered if it's possible to fit on my 3.0si, possibly with custom caliper carriers if needed, does anyone know if this is possible to fit these to a non M with minimal fabrication or modification?
Anyone with direct experience or know of anyone who's done this much appreciated.

Cheers,
Dan.

 

[TomK]

I think with the fronts you can either by using the Z4M hubs (to get the correct offset) which will also require the Z4M control arms since the ball joint is a different size, or you could machine the caliper carrier.
The rears would I believe require the Z4M trailing arms in order to get the hand brake to work.
Bit of a waste of time and effort really, there's not that much of a difference between the M and 3.0 brakes.

 

[srhutch]

I think with the fronts you can either by using the Z4M hubs (to get the correct offset) which will also require the Z4M control arms since the ball joint is a different size, or you could machine the caliper carrier.
The rears would I believe require the Z4M trailing arms in order to get the hand brake to work.
Bit of a waste of time and effort really, there's not that much of a difference between the M and 3.0 brakes.

As above I can't see the point either, they still look shite. I would try and get some 4/6 pots.

 

[bmwaddict]

I'm not really bothered about them looking better, they are more powerful with a larger diameter disc, I know they perform better than mine as we regularly go on cruises and my brakes don't stand up to his, and as my mate is selling them will get them at a decent price, unfortunately can't afford any 4/6 pots or BBK presently.

I'm asking more for advice and help on how/if they fit rather than opinions on how they'll look or if it's a waste of time but thanks both for input.

Machine Monkey has said he will give me a hand once I get hold of them to try and work out if it's doable without too much faff.

 

[Fishy Dave]

Hi Dan,

This thread may help? http://forum.e46fanatics.com/showthread.php?t=913537

It looks like your calipers are used on plenty of other models, including the E46 330i mentioned above. http://www.realoem.com/bmw/enUS/part?id=AL92-EUR-12-2000-E46-BMW-330d&mg=34&sg=05&diagId=34_0757&q=34116765881

 

[bmwaddict]

Hi Dan,

This thread may help? http://forum.e46fanatics.com/showthread.php?t=913537

It looks like your calipers are used on plenty of other models, including the E46 330i mentioned above. http://www.realoem.com/bmw/enUS/part?id=AL92-EUR-12-2000-E46-BMW-330d&mg=34&sg=05&diagId=34_0757&q=34116765881

Hi Dave,
Thanks, that's definitely helped as it looks very possible with slight machining of carriers.
I was aware the brakes on my 3.0si are straight off an e46 330i and possibly other models too, but thanks!

 

[GuidoK]

I dont know if milling 7mm off the existing brackets in that spot would be a good idea strenghtwise. 7mm sounds like quite a lot to me.
But the front z4m discs can be used very well in combination with the 135i performance calipers (multiple suppliers for matching brackets).
Sometimes you can snag them off ebay but as this mod becomes more and more popular, the time that you could get some for really cheap is over I think. You can also use them with some porsche calipers (and matching brackets), which might be a more affordable option. The z4m discs are not only larger, but also thicker (so vent canals vent more air) and semi floating with an aluminium center (so some weight reduction on rotary, unsprung mass).

For the rear brakes you cant just use M trailing arms because both the wheelbearings wouldt fit and the driveshafts wouldnt fit.
3.0si driveshaft in z4m wheel bearing is no go and Z4m driveshafts wont fit a 3.0si diff....

 

[bmwaddict]

Thanks for the info GuidoK, 7mm does sound like a lot as the brackets aren't that thick, mate is doing 135i performance calipers that's why I may have these z4m ones! Unfortunately can't afford them myself right now, but thanks for the info.
Will look into Brembo Porsche ones, a lot of guys on my old e36 forum did that mod to their m3s.

Is it a must to upgrade rears when upgrading front calipers/discs or could I get away with just doing the fronts?

 

[TomK]

Thanks for the info GuidoK, 7mm does sound like a lot as the brackets aren't that thick, mate is doing 135i performance calipers that's why I may have these z4m ones! Unfortunately can't afford them myself right now, but thanks for the info.
Will look into Brembo Porsche ones, a lot of guys on my old e36 forum did that mod to their m3s.

Is it a must to upgrade rears when upgrading front calipers/discs or could I get away with just doing the fronts?

Of course you can 'get away' with just doing the fronts, you're just going to be altering the brake balance forwards. I wouldn't do it myself but that's my opinion which you can choose to take the wrong way if you like again. :roll:

 

[bmwaddict]

Thanks for the info GuidoK, 7mm does sound like a lot as the brackets aren't that thick, mate is doing 135i performance calipers that's why I may have these z4m ones! Unfortunately can't afford them myself right now, but thanks for the info.
Will look into Brembo Porsche ones, a lot of guys on my old e36 forum did that mod to their m3s.

Is it a must to upgrade rears when upgrading front calipers/discs or could I get away with just doing the fronts?

Of course you can 'get away' with just doing the fronts, you're just going to be altering the brake balance forwards. I wouldn't do it myself but that's my opinion which you can choose to take the wrong way if you like again. :roll:

Thanks, I only ask as its a big job on the rears, and as the M rear caliper piston diameter is identical to the 3.0si one, and disc is only 8mm wider there doesn't seem much point.

I'm grateful for any input, including yours, I don't see how I took it the wrong way, I just disagree with your opinion it's a waste of time, but I'm very grateful for yours and any others opinions on this matter, which is why I thanked you in the reply post, which are duly noted, as I'm far from an expert in this area.

 

[TomK]

Thanks for the info GuidoK, 7mm does sound like a lot as the brackets aren't that thick, mate is doing 135i performance calipers that's why I may have these z4m ones! Unfortunately can't afford them myself right now, but thanks for the info.
Will look into Brembo Porsche ones, a lot of guys on my old e36 forum did that mod to their m3s.

Is it a must to upgrade rears when upgrading front calipers/discs or could I get away with just doing the fronts?

Of course you can 'get away' with just doing the fronts, you're just going to be altering the brake balance forwards. I wouldn't do it myself but that's my opinion which you can choose to take the wrong way if you like again. :roll:

Thanks, I only ask as its a big job on the rears, and as the M rear caliper piston diameter is identical to the 3.0si one, and disc is only 8mm wider there doesn't seem much point.

I'm grateful for any input, including yours, I don't see how I took it the wrong way, I just disagree with your opinion it's a waste of time, but I'm very grateful for yours and any others opinions on this matter, which is why I thanked you in the reply post, which are duly noted, as I'm far from an expert in this area.

Sorry maybe it was me that mis-understood.
It was kind of my point originally that it was a waste of time in that for quite a lot of work there is not a huge amount of difference in the braking capabilities between the 2 systems. As you've noted the rears in particular are quite similar... The M discs will be thicker, which will help in dissipating heat but won't increase the performance in a one off situation. Since if you say the piston sizes are identical (double check that though as Z4M/CSL rear calipers have very slightly bigger piston size than the standard m3 ones (to balance for the larger 345mm front disc of the Z4M/CSL setup) then you would probably be absolutely fine doing the fronts in all likelihood. Really you only want to be too concerned with balance if you start shifting it too far rearwards. The pad surface area and compound is also something that would differentiate the 2, I assume again they are pretty similar?
Is the brake master cylinder not different also on an M?
All in all though if you were to do the rears and fronts I just think it's a lot of faff for not a lot of gain. Better imo save towards a 2nd hand set of calipers such as k-sport, the pbmw calipers or the 996 setup. If you are happy with machining those brackets for the fronts then I guess it's not such a bad idea just to do them, but as Guido points out it's a lot of metal to remove from a fairly critical part. Otherwise you need to change hubs and things as I suggested which would start to get expensive.
I assume you have upgraded the brake fluid and pads in your oem setup? If not this is where I'd be spending my money if it's a bit tight.
All the best with it.

 

[GuidoK]

Indeed you'll get more front bias due to larger disc (and maybe larger piston? dont know from memory).
More front bias is never unsafe, but is performance wise not the optimal performance you can get from the hardware.
The best setup is that in every situation your fronts lock up just before the rears (and not way before the rears).
So you could get a more aggressive rear pad.
The rear M disc is also much larger than the rear z4 disc (294mm vs 328mm)
But the bias is not totally comparable just on disc size (larger disc=more brake torque) or piston size (larger piston=more clamp force) or pad size (larger pad, more force potential), also the master brake cylinder is different. Info on this is very limited, but what I have found suggests that the normal z4 mbc has a more rear bias valving than the z4m mbc has.
So its really a mixed bag of different components and usually experimenting should point out if the bias is ok.
My guess is that when fitting front z4m brakes and the rest stock will give more front bias, giving room for more aggressive pads in the rear.
Dont ask me what a more aggresive pad is, as that is also temperature dependable.
Fitting rear z4m brakes requires a lot of custom fabrication whatever path you choose to make them fit.

Fiddeling on your car is never a waste of time, its a hobby (hobbies are objectively always a waste of time, but also a way to spend time)

as for the safety bit I'm usually not afraid to mess with brakes, but in this case there's a lot of material to be removed from the front brakes.
The front brakes get in normal situations probably over 80% of all forces to endure, so they are way more critical in both construction and use than the rear brakes, so removing so much material from a front or a rear bracket makes a lot of difference in my book.

 

[bmwaddict]

TomK, thanks, I'm still researching, but yes I have performance brake fluid and uprated pads already.

GuidoK, thanks, much to ponder, I will be speaking to my auto engineer mate before getting the carriers machined 5-7mm to make sure it's completely safe, as it's such an important component being brakes.

 

[bmwaddict]

Anyone done the Brembo Porsche 996 caliper upgrade? I've read they're quite wide and may require spacers. Does anyone know if they're usable in conjunction with z4m discs? I know they fit straight on to my 3.0si 325mm discs.
TIA.

 

[Fishy Dave]

Sounds like excellent advice, just to add that i wasn't suggesting that you should machine bits off calipers/brackets, only that someone out there has made them fit.

 

[bmwaddict]

Sounds like excellent advice, just to add that i wasn't suggesting that you should machine bits off calipers/brackets, only that someone out there has made them fit.

Cheers Dave, I'll be talking with a mate of mine who's a mechanical engineer before doing anything like that. I notice you use blue stuff pads, and read what you wrote in a thread about them a little while back, I'll be trying them as the reds and yellows I use currently fade too quickly for my liking.

 

[peteslag]

I keep my standard brakes in good condition and use blue stuff pads, standard pagid discs with 5.1 fluid (2004 3.0 SE). 6000 miles and two track days later I've never experienced any form of brake fade. There is a lot to be said for keeping your braking system in good condition and using quality pads. I'm always up for a bit of modding but only if the pay off exceeds the effort put in!

The only down side to Blue stuff is that they can start to disintegrate after being on the car for a couple of years. It doesn't bother me, they are really cheap compared to other equivalent performance pads so I'll just change them if they make it to being on the car for two years.