Best retrofit for M3 brakes?

I believe the gt350 front calipers are 34mm/36mm/38mm.

What would the best rear option? The rear gt350 calipers are really inexpensive but haven't seen a mounting solution.

Bigblockfox wrote

I work at a ford dealer so got a great price on the gt350 front and rear calipers. Just need to pick up caliper brackets. Hoping someone comes out with the rear caliper brackets as well.

Ctsvbrakeswap sells the braket for the front.

Read this thread front to back about 10 times. Anyone with the Alfa 6 pot fronts have an update on how things are holding up? Seems like Unicorn fell out of favor with the setup and/or had to go with a custom pad route.

Freakyparts is saying the 360mm and 380mm rotor brackets will have the same exact unswept pad area, which conflicts a couple of the anecdotes on here...

I have the freaky bracket, Alfa caliper, and oem bmw 360 rotors. I use d1666 red stuff pads for full sweep. There is a very small fitment / alignment issue with the freaky bracket. It leaves a small (1-2mm) lip on the top of the pads leading to some rotor shudder after a few thousand miles. I just sand it off when I rotate tires. Other than that they work fine. I have f8x on the rear.

See pic of the lip. If I had to do it over, I would have waited for a complete used stoptech kit.

mugrug01 wrote

I have the freaky bracket, Alfa caliper, and oem bmw 360 rotors. I use d1666 red stuff pads for full sweep. There is a very small fitment / alignment issue with the freaky bracket. It leaves a small (1-2mm) lip on the top of the pads leading to some rotor shudder after a few thousand miles. I just sand it off when I rotate tires. Other than that they work fine. I have f8x on the rear.

See pic of the lip. If I had to do it over, I would have waited for a complete used stoptech kit.

Thank you for your input and pic!

Do you have a pic of front and rear of your car with that brake set up?

mugrug01 wrote

I have the freaky bracket, Alfa caliper, and oem bmw 360 rotors. I use d1666 red stuff pads for full sweep. There is a very small fitment / alignment issue with the freaky bracket. It leaves a small (1-2mm) lip on the top of the pads leading to some rotor shudder after a few thousand miles. I just sand it off when I rotate tires. Other than that they work fine. I have f8x on the rear.

See pic of the lip. If I had to do it over, I would have waited for a complete used stoptech kit.

Have you tired the smaller D1116 stock alfa pad size? Will leave a rust ring, but perhaps not give you a shutter issue if it's caused by the over sized pad.

FYI shudder issues are also common on stoptech brakes, so i wouldn't assume you'd be immune to them.

The lip on the brake pad would be the same on d1116 pads too. The pad itself is the same just longer on d1666. The freaky bracket hole location is off by 1-2mm causing the whole caliper to sit inwards on the rotor causing the pad lip.

A few pictures as is today.

mugrug01 wrote

I have the freaky bracket, Alfa caliper, and oem bmw 360 rotors. I use d1666 red stuff pads for full sweep. There is a very small fitment / alignment issue with the freaky bracket. It leaves a small (1-2mm) lip on the top of the pads leading to some rotor shudder after a few thousand miles. I just sand it off when I rotate tires. Other than that they work fine. I have f8x on the rear.

See pic of the lip. If I had to do it over, I would have waited for a complete used stoptech kit.

So does that mean you’re running F/R 360/370 mm OD rotors? Have you calculated the brake bias with the caliper and rotor combos?

Correct 360/370. Original goal was to use f80 380’s but they didn’t clear my oem219 18’s. The front bias with this setup is 64% vs oem 63%. The bigger downside is loss of rear brake torque vs oem.

I’m probably going back to oem rear this summer when I do suspension refresh. The 370 rotor and f80 caliper is for sale if anyone wants it (~20k miles on rotors).

Has anyone ever used seemslegitgarage’s adapters to allow the use of f80 CCB/2NH/G8x/F9x front 6 piston calipers with f80 rotors?

https://www.seemslegitgarage.com/product-page/e9x-m3-f8x-big-brake-kit

From what I found is that they designed the kit around the g8x calipers and pads. The g8x rotors are 380x36mm so im assuming these were made with the shims to have good pad sweep?

Anyone that can help me with an f13 m6 to e90 m3 brake retrofit? I got a really good deal on a full set of calipers that I couldn’t pass up so I want to do this swap

Anyone know why BMW produced the 2009 E90 M3 with such inadequate brakes for the weight and power of the car?

They didn't, put some solid track pads in and send it. I track stock sized PFC front rotors and OEM calipers with PFC08 pads and have zero issues on track, granted, I only run street tires, Mich PS4S. The OEM brakes can take a lot more than folks give them credit for.

soberin wrote

Anyone know why BMW produced the 2009 E90 M3 with such inadequate brakes for the weight and power of the car?

Nothing wrong with the stock brakes when set up right.

Most people installing BBKs to hard park at cars and coffee will never need them.

soberin wrote

Anyone know why BMW produced the 2009 E90 M3 with such inadequate brakes for the weight and power of the car?

They work quite well if you don't worry about what they look like.

As tdott and amg6975, the stock braking system is more than adequate for the e9x M. With proper pads and brake fluid, they can handle the heat generated from 20 min track sessions without fade. However, I personally have found the stock brakes to be inadequate for 40-45 min sessions on high speed and brake demanding tracks and this is why I switched to PFC brake kits. Brake heavy tracks with extended track time sessions are brutal on the stock brake setup but the brakes never created an on-track safety issue (pedal feel changed around the 30 min mark). The PFC (Z54/Z45 and Z31/Z31) brake setups had zero issues and gave you 100% confidence that they’d slow the car every time you nailed the brake pedal.

Partee has a brembo kit

M3SQRD wrote

found the stock brakes to be inadequate for 40-45 min sessions on high speed and brake demanding tracks and this is why I switched to PFC brake kits.

I agree but also wanted to to point out that use case is very rare, esp from the type of people asking these questions.

They are almost always a beginner driver that thinks they need a bbk and a ton of mods before doing their first track day.

tdott wrote

I agree but also wanted to to point out that use case is very rare, esp from the type of people asking these questions.

They are almost always a beginner driver that thinks they need a bbk and a ton of mods before doing their first track day.

I agree 100%. When first starting out, track beginners need to realize the best place to spend money is on the driver mod, not brakes, race seats, roll bar, etc.

soberin wrote

Anyone know why BMW produced the 2009 E90 M3 with such inadequate brakes for the weight and power of the car?

can absolutely confirm that. even on the Nordschleife. Some PFC or Endless pads, brake cooling from a GT4 lip, good brake fluid and you're really good to go.
Sure a BBK offers that "safety" as it never operates at 95%, but still. Those fat ugly single piston calibers do a pretty good job.
But you don't get any rewards at any Cars'n'Coffee with them. Even when you paint them red or blue.

cnasher wrote

I found the combination of m4 calipers with Maserati quattroporte 6 piston (30,34,38mm) and Porsche Panamera rear 4 piston (32/32mm) should work well. Has anyone come across plans for brackets?

Using 360mm front and 350mm rear rotors....What would be the break bias using this combo?