F80 M3 / F82 M4 Brake Caliper/Rotor Retrofit Guide to E9x M3 - Using OEM Parts

[0-60Motorsports]

Originally Posted by Viper4

Curious on everyone's take here. I'm almost done with the swap and I have a question about brake lines. I have a StopTech set of E92 stainless brake lines that have been waiting to go into the car. I've installed them along with this conversion. The odd thing is that the male threading is much longer than the female well on the caliper, especially in the rear. So this means the lines aren't screwed in to the top of the threading and flush with the backstop. I reason that the only thing holding the lines in place is the tension from being bottomed out and slightly torqued. Think that is sufficient? The fix could be me getting a lug nut that I tighten down on the caliper once the line is screwed in as far as it can go. BTW, I wish BMW made the caliper retaining bolts a little better haha, and maybe not an Allen head. #stripped

TIA!

Nice DIY. Thanks for posting.

[6ixSpd]

OEM F8X 6pot fronts would be great. Wonder if they work with the 380mm iron rotors though.

[SYT_Shadow]

Originally Posted by 6ixSpd

OEM F8X 6pot fronts would be great. Wonder if they work with the 380mm iron rotors though.

Oem ccb calipers take the m2c iron rotors, plug and play

[tdott]

Originally Posted by 6ixSpd

OEM F8X 6pot fronts would be great. Wonder if they work with the 380mm iron rotors though.

I don't think so without some custom work, the 6pot caliper from CCB or M2comp would require the 400mm M2comp rotors to be bolt-on.

[tdott]

Adding a quote from @Terra on the math for a quick brake bias calculation which shows it's close enough to not matter.

Originally Posted by terra;n17176

Quick napkin math: F8x: Fronts are 4 x 40mm piston with 380mm rotors, rears are 2 x 44mm piston with 370mm rotors. That makes the ratio about 1.69:1 or about 62.9/37.1

E9x: Fronts are 60mm with 360mm rotors, rears are 46mm with 350mm rotors. Results in 1.75:1 or 63.6/36.4

I think that's close enough to be fine. Doubly so when you consider the cars are similar in size, weight, weight balance, etc.

[HP Autosport]

Did you happen to take any photos of the spindles side by side? I wonder if there are any geometry differences that may positively or negatively affect handling.

[W///]

That's pretty neat. I think the OEM E9x M3 brakes are probably the weakest link of the car. It's not bad per se, but when you get out of say a Porsche, it feels like brakes from a school bus. Also don't find them as confidence inspiring as my stock Z4MR brakes.

[GeorgeA]

Will F80 hubs and bearings work on our cars? So I can run F80 spindles, hubs and bearings with the brake setup.

[Lorde]

Nice work!!

[tdott]

Originally Posted by HP Autosport

Did you happen to take any photos of the spindles side by side? I wonder if there are any geometry differences that may positively or negatively affect handling.

Measurements were done in the mega thread, here is some info:

Originally Posted by KevM3UK

carefull measurements of the centrelines and angles of the balljoint holes, if this is different then its game over ! indeed they are exactly the same







Now this is the one where its slightly different, note the four holes for the wheel bearing , they sit around 4-5 mm lower on the M4 spindle, making the length from the strut top mount to the wheel centre 4-5mm longer, this will raise the car's ride height ever so slightly, we'll see later on!



also the E92 wheel bearing fits exactly to the m4 spindle, i tried it off the car first then bolted the disc on and caliper, its plug and play with no altering of the track ,the wheels sit exactly the same and i still use my 10mm spacer with no ill affect.

https://www.m3post.com/forums/showpo...&postcount=141

[tdott]

Originally Posted by GeorgeA

Will F80 hubs and bearings work on our cars? So I can run F80 spindles, hubs and bearings with the brake setup.

Yes the front wheel bearings are interchangeable. They will require the use of M14 lugs so your existing lugs/studs will not work with the f8x hub. The rear I am not sure about but in theory it should be also, but it's a lot more work to press out the rear bearing to remove the hub.

[PARTS@STBMW]

This is awesome. Thank you for sharing!

[GeorgeA]

Originally Posted by tdott

Yes the front wheel bearings are interchangeable. They will require the use of M14 lugs so your existing lugs/studs will not work with the f8x hub. The rear I am not sure about but in theory it should be also, but it's a lot more work to press out the rear bearing to remove the hub.

Got it, thank's for the information.

I wouldn't want to switch the rear bearings since they are fine and the process is a bit intense. I'd be running M14 in the front and stock in the rear. Might still be worth doing though.

[Ghostriderf80]

Originally Posted by tdott

Since the original thread is too long, I figured it would be useful to combine all of the info in one place that is easier to follow:

I've been getting a lot of questions about my F8x M4/M3 brake upgrade, so I thought I'd give an overview on how it is done and what parts are required. This is not meant to be a step by step DIY but a guide on how it's done since it's really pretty simple with the right parts.

They can also be done using F8x CCB setup or M2 Comp parts as well.

Part list:

• F8x Calipers and Rotors/Pads
• F8x Spindles
  Right: 31212284002
  Left: 31212284001
• 4x M12 Flat washers, ideally around 2mm thickness.
• F8x dust shields or you can cut trim the e9x ones.
  (also not a bad time to do brake ducting with a custom backing plate if you wanted to go that route)
• Wheel bearing bolts (one time use)
  31206783065 - M12X1.5X45 - (x8 - 4 per wheel bearing)
  These bolts are required because the f8x carrier has a ball seat vs e9x which is flat
  These are not the ones from an f8x since the f8x wheel bearings are a different thread pitch, I ordered these ones new from FCP Euro.
  
• New Brake lines are recommended, I went with E9x M3 Stainless steel lines from FCP Euro

Finally, you need to decide how to handle the ABS sensors. Since the F8x sensor location is slightly different requiring you to change the orientation of the E9x ones to read correctly.
Some have cut the e9x ones and created a holder out of metal.
Using the abs live obd2 reader, I was able to get the sensor to read correctly in this position (cut portion facing towards the outside center of the hub)

Eventually I bought 2 F8x sensors and spliced them into the E9x connectors and they worked perfectly and I was happier with that solution but both will work.



Full Install notes are on my blog with more pictures, not meant to be step by step but will give you a guide, it's fairly straight forward but I do include a few tips.

https://www.tdott.me/2020/04/project...on-e92-m3.html

I totally appreciate that you have a hoist in your garage. I mean the swap is cool, not sure of the cost, but the hoist does it for me.

[tdott]

Originally Posted by Ghostriderf80

I totally appreciate that you have a hoist in your garage. I mean the swap is cool, not sure of the cost, but the hoist does it for me.

Thanks, definitely one of my favorite things. I made sure before buying this house the height in my garage would at-least allow for it even tho it's not enough for a full size lift, the lift has paid for itself several times over. I wish I had done it sooner.

[SYT_Shadow]

Originally Posted by tdott

Thanks, definitely one of my favorite things. I made sure before buying this house the height in my garage would at-least allow for it even tho it's not enough for a full size lift, the lift has paid for itself several times over. I wish I had done it sooner.

Lifts are so wonderful... one day I'll have one again

[Ghostriderf80]

Originally Posted by tdott

Thanks, definitely one of my favorite things. I made sure before buying this house the height in my garage would at-least allow for it even tho it's not enough for a full size lift, the lift has paid for itself several times over. I wish I had done it sooner.

Originally Posted by tdott

Thanks, definitely one of my favorite things. I made sure before buying this house the height in my garage would at-least allow for it even tho it's not enough for a full size lift, the lift has paid for itself several times over. I wish I had done it sooner.

Defo something I will be getting too. Good set of tools makes the difference

[Lento]

Great guide, thank you

[g35mt]

tdott,

you mentioned that you got the f80 abs sensor. When you splice to the e92 connector, you just wire the same color coded wired? it is the same number of wire?

[tdott]

Originally Posted by g35mt

tdott,

you mentioned that you got the f80 abs sensor. When you splice to the e92 connector, you just wire the same color coded wired? it is the same number of wire?

Yes it's only two wires.

[g35mt]

Originally Posted by tdott

Yes it's only two wires.

thank you sir. When i bought the spindle, it came with it. I remember mentioning in the original thread about getting the f80 abs speed sensor and splicing it. Wasn't sure but you just confirm it. Thank you very much.

[ebisu8]

If anyone is interest, I just removed my 2020 M2C brakes in favor of AP Essex brakes. They had 181 miles of use during my break in period. So they were treated quite well. Send me a PM if interested. Full setup, F/R Calipers, Rotors, Pads and lines plus front heat shield.