BBK for 35i
- Thread starter stijohnny
- Start date
sumotan said:
370mm discs is correct, the 380mm ones won't fit as the offset is different. The calipers themselves are fitted to the M2, M3, M4, 340i and 440i.
It won't cause any problems with balance at all. Rear brakes actually only do something between 15-20% of the actual work. This is why you see small hatchbacks that still use drum brakes even today, not because of the factories being cheap but because putting discs on the back would mean they're not doing enough to prevent corrosion and seizing up of the calipers.
For further reference, I believe 370mm and 324mm is very close to what Jaguar put on the F-Type which is has similar balance to Z4's
Thanks Player 1, I like Johns setup there and may take you up on that. Do you know if the M5 6 pot caliper can be made to fit? Like these:- https://www.ebay.co.uk/itm/BMW-M3-M4-M5-F10-F80-CCB-Brake-calipers-Brembo-6-Piston-Gold-Used/164665446334?hash=item2656d34fbe:g:JmEAAOSwzM5gDa~d I am running 19in Beyern wheels with 5mm spacers. Also please get me a price for the discs and pads to go with those 4 pots if poss.Player 1 said:Hi, I fitted the M4 brakes to John's car above and can definitely attest to the improvement. If you're interested at all, I can send you a set of refurbished and powder coated calipers at £600 and can also get an up to date price on the discs too?
stijohnny said:
No problem at all, I will find out the prices of discs/pads I used last time too, I doubt they've changed much but I've had some proper yoyo pricing with suppliers in Europe! Any questions, just give me a shout
I did look into the M5 calipers back along as well, it is possible to make them fit however will require specialist brackets and is roughly double the price once it's all done. I can offer a reman a set at £910.
The first thing I found was that the gold ones and the blue ones are actually slightly different. the gold ones have slightly more material at their mounting points so will sit further out from the hub, if that makes sense? The end result was that you'd definitely need the blue calipers to fit correctly with another BMW brake disc.
The discs you'd need are the optional 400mm discs off of an M2 Competition, the F10 M5 discs won't fit as they're a different hub bore.
These guys will do the brackets which will fit Z4's and other F/E series cars:
https://www.vagbremtechnic.com/front-caliper-carrier-kit-allows-fitment-of-m5-m6-f10-f12-6-piston-brembo-calipers-to-oe-400mm-discs-ak0009/
Regarding brake bias with these, the overall piston area on the M5 calipers is actually only around 1% larger than the four piston calipers so shouldn't be any issues with the master cylinder not being able to pump enough fluid.
With that said, I do know a lot of the guys with E9x 335i's etc that have put these calipers on have changed their master cylinder to an M3 one and said pedal feel is better. Unfortunately this isn't an option for the Z4 as the master cylinder is completely different, it may be that the Z4 cylinder has a higher capacity than the 3 series one in the fist place however I don't know for sure I'm afraid!
stijohnny said:
same question as R60BBA, but i'd also ask what are you trying to achieve with upgraded brakes, and what have you changed so far?
the biggest disc, multi-piston calipers won't do squat if the brake pads are still cheapo OEM items and the brake fluid hasnt been changed for a few years.
Mm, if you’re 100% sure that you’re gonna do track work then invest in a BBK.stijohnny said:
But if you’re not sure about it, I would recommend replacing your set up with OE.
Note that in general BBK’s don’t actually stop your car any quicker than standard brakes do, all they do is allow you to repeatedly brake hard without fade (which is why they are a great upgrade for a car used on track, but overkill for a car used solely on the road).
Also if you are going to do a BBK, invest in a proper kit which has been designed specifically for your car, ie one from the likes of AP, Alcon, Stoptech etc. Avoid makeshift upgrades such as slapping M3 brakes on your car as this could make your braking performance worse.
Usually a happy medium for an enthusiast who wants to push their car on the road and perhaps do light track work is to uprate the pads (ie Pagid RSL29), lines (ie Hel Performance) and fluid (ie Castrol SRF). This is also much friendlier to your wallet too and will provide the best “bang for buck.”
More of a review if you fancy going down this route...
Fitted PB brakes front 6 pot kit with 2 piece discs, very impressed with the fitting and quality! Currently using PBs "sports pad" option and they're mega, for the road at least, with some proper fluid in!
https://www.pbbrakes.com/bmw-z4-e89-09-up-front-big-brake-kit.html/?SID=pn0j1il1bhp9pse6vp9bbtc8a2
Fitted PB brakes front 6 pot kit with 2 piece discs, very impressed with the fitting and quality! Currently using PBs "sports pad" option and they're mega, for the road at least, with some proper fluid in!
https://www.pbbrakes.com/bmw-z4-e89-09-up-front-big-brake-kit.html/?SID=pn0j1il1bhp9pse6vp9bbtc8a2
:roll: AP, Stoptech, don’t do brake kits for the E89, Alcon used to but I think have stopped them as not enough demand but I could be wrong on that, have to check.
The M4, not M3, stoppers work very very well, have so much more feel than standard, pull you up harder from spirited runs, with zero downside. The cost of the conversion is well worth it imho, as I said I wouldn’t go back to standard after having these on the car, there really is no downside. The servo is more than up to the job, no issues whatsoever. If you’re anywhere near the Peak District you’re more than welcome to try them for yourself.
The M4, not M3, stoppers work very very well, have so much more feel than standard, pull you up harder from spirited runs, with zero downside. The cost of the conversion is well worth it imho, as I said I wouldn’t go back to standard after having these on the car, there really is no downside. The servo is more than up to the job, no issues whatsoever. If you’re anywhere near the Peak District you’re more than welcome to try them for yourself.
Thanks John e89, Player 1, Robbo and all for your guidance and knowledge on my brake question. My car is sorn until at least the end of March so it gives me a few weeks to choose the course of action to take and so far I am thinking the M4 caliper option should suffice. I took the front bumper off last weekend to prepare it for a respray as it has a few scratches and scrapes mostly underneath, once it's all back together I'll put some pics up.