E46 Budget Big Brake Kit | under $500 for front calipers,rotors,and pads

breakabolt · Oct 4, 2019

DISCLAIMER: ***8220;Brakes are one of the most important components of a vehicle. Please do your own research or consult a professional if you***8217;re not comfortable in doing it yourself. Improper brake setup could damage your car and cause accidents, which could lead to property damage, injuries or death. I do not take any responsibility and I***8217;m not liable for any damage caused by the retrofit, please use your own discretion. ***8220;

FYI: I am not a professional mechanic. Like most, I***8217;m passionate about cars and love working on them. I***8217;ve done some research about e46 brakes, but it is such a vast topic and I may not have all the information. So feel free to add in or correct me if I***8217;m wrong. Thank you in advance.

Hi everyone,
I***8217;m building a N54 twin turbo swapped E46 wagon.https://forum.e46fanatics.com/showthread.php?t=1259743

One of my goals was to upgrade the stock e46 325it brakes with a big brake kit (BBK). Most BBK kits start around $1k and above. I was looking in to retrofitting 135i front 6 piston calipers which still cost around 1k with all the hardware at the end of the swap. So, I started to work on retrofitting 2009 E90 335i front brakes from my donor car. I***8217;m using e46 m3 rear calipers with a complete E46 M3 rear end.
I do not know if there***8217;s going to be any performance benefit yet. The N54 swap is not complete , will chime on the thread once it***8217;s done. However, the bigger rotors should benefit with heat dissipation and looks awesome as well.

I haven***8217;t done the calculation on brake bias with my current setup, but I***8217;d like to know if someone could calculate it for me to compare with stock brake bias.
2001 bmw 325it
E46 325it master cylinder
E90 front caliper and rotor (348x30) 57/30/348
E46 m3 rear caliper and rotor (328x20)

Comparison of different rotor sizes:
FRONT / REAR
E90 335i - 348x30 / 336x22
E46 M3 -325x28 / 328x20
E46 M3 Comp -345x28 / 328x20
E46 330i -325x25 / 320x22
E46 325i -300x22 / 294x19
CEIKA BBK 4pot -346x32 / 330x28
Stoptech st40 -332x32 / 309
Stoptech C43 -332x32 / 309

Required parts for retrofit:

2007-11 E90/92 335i front calipers (can get used on ebay for around $100-200 per set) Remanufactured from ECS $175 per caliper.
https://www.ecstuning.com/b-centric-parts/remanufactured-brake-caliper-front-right/34116773202rkt/?gclid=EAIaIQobChMIhqbCqoSD5QIVWyCtBh2yuwWfEAkYBiABEgLjWvD_BwE

E90/92/93 335 front Rotors ($120- $300+ per set depending on the brand)
https://www.ecstuning.com/b-zimmermann-parts/front-brake-rotors-pair-348x30/34116855000kt1/

E90/92/93 335 front brake pads ($60- $300+ per set depending on the brand)
https://www.ecstuning.com/b-brembo-parts/brembo-brake-pads-front/34116794915~brm/

Existing E46 caliper bolts

20mm 120x5 hub centric spacer and extended lug nuts

E46/E90 brake lines

E46 90mm bolts to stud conversion kit (not required but makes it easy to swap wheels)

Required tools
17mm / 18 mm wrench
Grinder / sander
Other basic hand tools

Now that we have all the parts and tools, you have to get the spacer custom milled from a machine shop. As per below picture you have to make a grove on the hub side so the adapter will sit flat on the hub. You***8217;re going to have to get a custom ring cut and pressed on top of the hub adapter so, the brake rotor will centered to the hubs position. You may have slight differences in your own hub due to wear and tear so make sure to measure your hub first. I think E46 M3 and zhp has some differences so may want to check and make some minor adjustments. Check below picture for specs and reference.
Measurements were taken on E46 325it

Custom hub measurements.

E90 caliper

Spacer without grinding the lip of the hub.

Grind off the lip on the hub center. There is a ~3mm lip on the edge of the hub center.

Test fitting the hub adapter to make sure it sits flat on the hub

Set the hub adapter and rotor on the hub and use a extended lug bolt to hold the rotor. You can use a spacer in between or a wrench as a spacer for the moment. ( the rotor holding bolt is short for this application. You can get a custom bolt made or do a stud conversion)

Set the brake pads in the caliper. Without the pads the calipers are compressed by the metal spring and the rotor will rub on the caliper

E90 335i caliper will bolts directly on to the e46 carrier assembly. You can use the existing E46 caliper bolts or use e90 caliper bolts. (Need to make it short by grinding off, E90 bolts are a bit longer)

E46 brake line will work since it has the same thread size as the e90 brake line. The only difference I noticed was that e90 brake line has more threads compared to E46 brake line.

Bolt the wheel with extended lug nuts. It is a bit difficult to use lug nuts this setup in a hurry since you have to line the holes of the adapter, rotor, and wheel to the hub. In this case it is easier to do a stud conversion which helps with holding everything together. Furthermore, I***8217;ll probably get another hub centric ring fromthe inside of the hub adapter to extend so it'll hold the wheel better. Currently there is a lip on the adapter but it falls a little bit short.

NOTE : I'm using 18" wheels, I'm not sure if it'll work with 17" wheels.

325i stock vs 335i setup

That***8217;s about it we are done with the setup. Make sure to bleed the brakes and test the brakes before driving off.

Thank you, for reading through. Let me know if you have questions. I***8217;ll try to answer as best to my knowledge.

You can check out the video of me doing it on youtube, check the link below. If you are interested in more, please subscribe to my youtube channel. Likes, share and comments helps as well.

https://youtu.be/eiacEuYc56M

E46 m3 rear painted to match the front.

YoitsTmac · Oct 4, 2019

Nice write up. Am sad because my wheel fitment is so tight, no spacers of any kind can be used. Guess this DIY is out of my reach but probably available for many others.

breakabolt · Oct 7, 2019

The modifications do push the wheels a bit out. Even thou, its a 20mm spacer your technically gaining only around 16 - 14 mm. Because the rotor is placed over the adapter. Its basically equivalent to adding ~15mm spacer on a stock car.

breakabolt · Mar 10, 2020

I'm still looking to improve the front brake setup. Looking for a E46 M3 Competition / CSL Front Brake disk (345 X 28 Mm). I hope it'll fit the caliper and hub without the adapter.
Let me know if anyone has an old spare I could borrow to test fitment. I want to get one as soon as i get some $$$ but these rotors are stupid expensive.

breakabolt · Mar 10, 2020

I added the info on the main build thread of N54 E46 wagon build, but since this thread is about brakes I'm adding it here as well.
link to the main thread https://forum.e46fanatics.com/showthread.php?t=1259743&referrerid=1048263

Rebuilding E46 M3 rear brake calipers

https://www.youtube.com/watch?v=vsuczL_Q57Y

Using air pressure to remove the piston. FYI: it is under pressure, please keep your fingers away from the piston.

use a pick tool to remove the inner seal and replace the new seal. don't forget to lubricate them as well.

put the dust boot on the piston

push the piston in with all you might.

replace old guide pin boot.

https://i.ibb.co/PQQW44M/done.jpg
calipers are done with fresh seals.

Alex323Ci · Mar 10, 2020

interesting thread.

a lot of people don’t know the M3 CSL/ZCP rear caliper uses a larger brake piston. this should probably be a better fit brake bias wise with your larger front brakes (when possible to get) over standard rear M3.

breakabolt · Aug 26, 2021

UPDATE**********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE

DITCHED THE SPACER AND 335I ROTORS FOR E46 M3 CSL/ZCP ROTORS - IT'S A DIRECT FIT.

Here's an update on the brake setup. I did some testing with E46 M3 CSL/ZCP front brake rotor and they fit perfectly without any modifications.
The rotors are slightly smaller than 335i (335i- 348x30 E46M3CSL - 345x28) but its not much of an issue.

I had to use M3 hex bolts to hold the rotor in place. 325/330 bolts dont have the same concave style bolt.

Parts List. (Im linking to Turner motorsport site for the parts, but do some research to find the best prices. These rotors cost a pretty penny)

Genuine BMW Brake Disc, Ventilated, Left 34112282445

Genuine BMW Brake Disc, Ventilated, Righ 34112282446

Genuine BMW Inner Hex Bolt - 34111123072

Check below for the video with brake fluid flush using INPA

Rice_crispy · Jan 11, 2022

breakabolt said:
UPDATE**UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE***********UPDATE

DITCHED THE SPACER AND 335I ROTORS FOR E46 M3 CSL/ZCP ROTORS - IT'S A DIRECT FIT.

Here's an update on the brake setup. I did some testing with E46 M3 CSL/ZCP front brake rotor and they fit perfectly without any modifications.
The rotors are slightly smaller than 335i (335i- 348x30 E46M3CSL - 345x28) but its not much of an issue.

I had to use M3 hex bolts to hold the rotor in place. 325/330 bolts dont have the same concave style bolt.

Parts List. (Im linking to Turner motorsport site for the parts, but do some research to find the best prices. These rotors cost a pretty penny)

Genuine BMW Brake Disc, Ventilated, Left 34112282445

Genuine BMW Brake Disc, Ventilated, Righ 34112282446

Genuine BMW Inner Hex Bolt - 34111123072

Check below for the video with brake fluid flush using INPA

Just wondering if using a stock.330.rotor with a 335 caliper owuld work

IdahoDoug · Aug 26, 2021

Did you do any stopping distance testing, before vs after?

breakabolt · Aug 26, 2021

I didn't do any testing before the swap. This was part of the N54 E46 wagon I'm building. Here's the link for the build.
N54: n54 engine swapped e46 wagon build thread

And I'm not sure if you could use the braking distance from my car as a baseline. since its highly modified in terms of power, weight, suspension, and weight balance. compared to a stock E46.
However, I'll try to get that info. currently, I'm trying to remedy some boost gremlins.

elfer · Aug 27, 2021

Great work, I love parts catalogue upgrades like this. Did you weigh the bits you took off and the bits you put on? There's no such thing as a free lunch, and the flipside of fitting bigger brakes is usually the increase in unsprung weight. Be interested to know the percentage increase.

A930rocket · Jan 12, 2022

Interesting thread, thanks for posting.

So, the E90 front caliper is a direct bolt on?

I bought a set of front E46 M3 calipers to use with the M3 CSL rotors on my 330, but it takes an adapter, which is on back order.

What is this surface area of stock E46 brake pads versus M3 versus E90?

E46VAL · Dec 19, 2022

Will the 335i calipers fit on an E46 330i with BMW style 50 wheels? 8x17 ET47?
And how about these wheel sizes: 8.5x19 ET40?

AvdB · Jun 26, 2023

Great work!

i am planning to do this in my car.
So, please post some more pictures. How do the pads fit the rotor?

E46 Budget Big Brake Kit | under $500 for front calipers,rotors,and pads

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