M3 Big(ger) Brake Kit

I always advise new students to not just throw money at their cars until they know how to drive it. The one exception being to address know weak points of the platform. With that in mind, I’m starting to prep my new M3. The E46 M3 stock front brakes aren’t up to extended track sessions out of the box. But they can be significantly upgraded without spending thousands of dollars on a big brake kit (though I’d be happy to sell you one.)

Here’s my take at building a bigger brake kit on a budget. This plan uses with the stock calipers, CSL caliper carriers (or a reasonable facsimile) and rotors. And the most important part, improved airflow and good pads. Brake pads of choice are PFC 08 compound.

What came on the car.

These calipers were only a few years old, but given the condition of the dust boots and unknown condition of the seals, I decided to get remanufactured ones rather than rebuilding them. Once you return the cores, remanufactured OEM calipers are only about $70 a side. Given that the rebuild kit is about $30, it was certainly worth $40 to me to have someone else do the rebuilding and cleaning of the calipers.

OEM CSL Caliper Carriers are $265 a side, but you can get a pair of ECS CSL style carriers for under $200. You have a couple of choices for rotors. Many people choose the PFC Direct Drive rotors which are about $760 a pair. I decided for this initial set-up, I’d use OEM BMW Motorsport CSL Rotors which I got from FCP Euro for about $440 for the pair. Like everything else from FCP Euro, when they’re worn out, send them back for replacement. Just pay for shipping. Bonus. Brake lines were replaced with StopTech braided stainless steel.

To improve initial bite and pad wear, I use brass bushings from ECS Tuning in replace of the stock rubber ones. Those run about $100/pair for the front and $60/pair for the rear.

All installed.

To paint or not to paint, that is the question? I’m of two minds when it comes to painting calipers. On the one hand, paint isn’t going to make you any faster. You could probably argue in fact it retains more heat. But on the other hand are aesthetics: cast iron calipers are going to rust. So why paint, besides aesthetics? Temperature sensitive ceramic paint can give you information about max temp sustained. I once had a Brembo brake engineer tell me that any time a stock caliper exceeds 550 degrees F, you need to rebuild the seals. So I use paint that discolors above 500 degrees and also use temperature strips on each caliper.

Brush paint seems to last longer.

It is easier if you paint before you install, but it is possible to paint afterwards if you take your time. I like to paint what I can with the caliper installed, then remove it to paint the back and hard to reach areas.

Improved airflow took a bit more effort. I haven’t deleted the AC yet, so I got the HardMotorsports Clubsport kit which includes the ducts that replace the fog lights, hoses, and clamps.

Between the bumper cover and the ducts, I used wire fabric to make grills.

Driver’s side with Y-pipe to the air box.

The 3-inch duct hose does restrict how far you can turn the wheel a bit. The kit ships with steering lock limiters to save your tires from rubbing the ducts.

Or just accept that you’re going to need new hose if you have to throw on some serious opposite lock. Since it turns out I can’t even back out of my driveway without contacting the hose, I decided to try a different solution. I ended up getting the hard Motorsports backing plates as well. Since you can’t get plates sized for the CSL rotors, we had to cut off the inner ring, but they still provide a good mounting point to feed air to the center of the rotor.

The final piece was the addition of the Hardmotorsports low profile brake ducts. I had to lose the Y duct to the air intake but I have another plan for that. I’m still working on the ideal location to mount them. Mount it too high and the hose hits the inside of the rim. Mount it too low and it rubs on the sway bar. I think I’ll still hit it at full steering lock, but the metal face should hold up to some abuse. At least now I can back out of my driveway without hitting it which is progress. I generally can only go to the track between March and October around here so I’ll probably just remove the hoses in the off season.

That’s how we roll

If you’re trying to run a square set-up on your E46 M3 and want to use 275 mm wide tires, you are going to want to roll the rear fenders. The stock fender has a huge lip that’s about 10mm wide. Using this simple tool from Eastwood, you can safely roll the fender and gain back 5-7mm of that. The process is fairly straight-forward if you work one section at a time and keep the paint hot to avoid cracking.

Roll with it.

Safely place the car on jack stands and remove the wheel. Bolt the tool to the hub and adjust it so the rolling wheel sits flat against the inside lip. Use the red lever to increase the pressure and slowly work the wheel back and forth on the fender lip, 6-8 inches at a time. Reheat the paint each time you pause to increase the pressure. I split the lip in thirds and worked each area before increasing the pressure. It took about 20 minutes to get the amount of clearance I needed.

I’m running a 9.5 inch wide wheel with an offset of 35. The tires are 265/35R18 Pilot Super Sports and I’m using a 10mm H&R Trak+ spacer in the rear so I’m thinking I can also run 275s without the spacers.

Moving Cruise Control to the Stalk

This is one of those mods that only makes sense once you’ve driven a stripped-out track car a great distance on the highway. You NEED cruise control. In your track car. Stay with me here.

This was going to be the year I finally got a trailer. But the opportunity to buy this M3 came along, so all of my money for the trailer went into this car. For now, it’s still street legal and I have to be able to drive it to the track and back. So to keep out of jail, I need cruise control. The problem is that the buttons for that were on the sport steering wheel which I replaced with Sparco wheel and quick release. I was able to salvage and adapt the clock spring so I still have a working horn button. That also means the wiring that controls the cruise control is still there.

The beauty of the design of BMWs of this era is that many parts are interchangeable. In this case, I’m going to grab a cruise control stalk off of an E85/E86 Z4. It plugs right into the clock spring housing and all you have to do is jump some wires and modify the housing.

Disconnect your battery and wait 15 minutes for the ABG module to power down (if you still have airbags.) Remove the steering wheel and the steering column housing. Remove the lower housing by pressing the center of the two pins and pry the lower half away from the top half of the column cover. Remove the screw from the top of the housing but you don’t have to remove it from the column, just slide it up to get access to the clock spring set screws.

You’ll need a suitable CC stalk (part number 61316940989) and plug 61138380696. My plug came with four wires already installed. You will need to connect three of the wires. At the bottom of the clock spring, remove the ten pin connector and look at the end of it. The pins are numbered on each row of the connector. Then look at the side of the four pin plug referenced above for the pin numbers . Connect the wire from pin 10 to pin 4 (power); pin 8 to pin 2 (cruise control); and pin 7 to pin 1 (ground).

Plug the stalk into the housing and then plug the 10 pin connector back into the clock spring. Plug the four pin connector you just wired to the stalk and reattach the clock spring housing to the steering column. Replace your steering wheel and airbag if you have one. Reconnect the battery and you’re ready to test the system.

  • Pressing the steering column lever upwards (on): Cruise-control system on
  • Pressing the steering column lever upwards or downwards (off): Cruise-control system off.
  • Pressing the steering column button at the side (I/O): Activates resumption of cruise-control system. The vehicle accelerates or decelerates exclusively from non-controlled operation to the driving speed last set and maintains this speed.
  • Pressing the steering column lever briefly backwards (+): Sets the road speed. If the cruise-control function is activated, the current vehicle speed is kept constant.
  • Pressing and holding the steering column lever backwards (+): Increases the road speed. The vehicle accelerates for the period the switch is actuated up to its maximum speed.
  • Pressing the steering column lever briefly forwards or holding pressed (-): Brakes the road speed. The cruise-control system is deactivated for the period the switch is actuated. However, it is not possible for the driving speed to drop below the minimum set speed.

If it all works as planned, then you just need to modify the lower column housing to fit around the new stalk. The lower cover is part of the crash protections for your knees. Inside the cover is a metal plate and some expanded polystyrene foam. After you measure and cut the outside to make room for the stalk, you’ll also need to remove a little on the bottom of the cover to make room for the mechanicals of the stalk. Measure twice and cut once.

M3 Steering Wheel Refresh

If your leather steering wheel is shiny or slightly sticky, you need a good cleaning. If it is also a bit faded, that can be refreshed as well. See this post for detailed instructions.

Visit Colourlock.com and buy a Leather Fresh kit for your vehicle. They color match most OEM leather. You’ll want to also get a scrub brush and a sanding pad. If your steering wheel is in really bad condition, also get some leather cleaning spirit. All in, you might spend about $100, but compared to a new steering wheel, that’s a bargain.

Start by masking off the trim. (If you’re black trim is also in bad shape, consider recovering it with 3M film.) You won’t make a huge mess, but you do want to cover the instrument cluster and your lap. Wear gloves. The chemicals are not harsh, but they will dry out hour skin.


Start by using the cleaner and the brush. You’ll want to clean the entire steering wheel a couple of times. Keep cleaning until you don’t get any discoloration on the towel you use to wipe it off. If the wheel is in really bad condition, use the leather cleaning spirit as well (in a well ventilated area.) Once dry, lightly sand the entire wheel, paying special attention not to sand the stitching or sand too much. You just want to rough up the surface and knock down any imperfections. If you wheel has been refinished before, take special care not to sand too much, especially if it is a heated wheel. When finished, clean again with the leather cleaning spirit. Let dry.

Refreshed Matt FinishLeather Fresh is a leather dye that dries quickly to a matt finish. Work a small area at a time and dab it on with the sponge, don’t paint it on. Use a heat gun on low or a hair dryer on high to dry the dye. It can be handled as soon as it is dry, but wait 24 hours before applying any protectant. You’ll want to apply 2-3 light coats over the entire wheel and more where it was heavily faded. Give yourself about an hour for the entire project.

M3 with Spots

Those Spots

When I got this car, it had been under a car cover for about nine months. Included in the receipts was a recent bill for detailing. I couldn’t connect the dots, so to speak. How could this nose be so dirty when the car was recently detailed? Those spots weren’t dirt. That was mold. Ew.

Clear bra can be a great way to protect the paint of your car, especially along the the leading edge of the hood where it is subject to all kinds of debris. The key to remember, however, is that it is a disposable layer of protection. It’s supposed to be replaced periodically, usually every 3-5 years.

This clear bra was probably 10 years old. It was faded and cracked in places. It trapped water between the film and the paint and that’s where the mold developed. If the film isn’t too old, removal is just a matter of using heat to activate the adhesive, catching a leading edge, and peeling it off. No such luck in this case.

Every inch of this stuff had to be carefully scraped off by hand. Heat it too much and the film liquifies leaving the adhesive behind. Don’t get it hot enough and it won’t come off at all. In the end, what worked best was to heat a small area with a heat gun, then use a plastic scraper to scrape it off, much like paint removal on an old piece of furniture. I found an old credit card worked best. The plastic is harder than the film, but softer than the paint. Steam worked well on areas which weren’t petrified, like the mirror caps. There the film would come off in several inch long chunks, but on the hood it was all heat and scrape.

It took about six hours to complete. My reward when finished was a new roundel. I also polished the headlights while I was there.