[dradernh]

Originally Posted by damianbmw12

I tracked my e46 M3 about 50 or so events so I mostly know what to expect. I do have a couple questions as an F22 newbie.

- will my nice pretty blue calipers be trashed from braking hard? I am hoping BMW does something special to handle the heat, but I doubt it.
- what is a good pad that will hold up to the weight? With MPSS tires.
- assume Bmw brake fluid would not hold up?
- my E46 was easy to turn the nanny controls 100% off. I don't see how to do that in this car. Do you run in sport plus or hold dsc off and run it in normal? I want to be able to slide as much as an Xi will allow anyhow.

Thanks all

1) Only if you beat on them, or, possibly, are running on a heavy-braking track. I've run my car for 8 events at Mid-Ohio, which has one very heavy-braking zone and a handful of much lighter braking zones, and there's been no discoloration. Nevertheless, brake temperature paint on my rotors and temp strips on my calipers indicate that temps have gotten much higher than I would like. As a result, my pistons' dust boots are cracked and now require replacement. FWIW, I'm pretty easy on my brakes, having been coached by a pro driver on how to use them. My calipers still look like new, and my DTC-70s are less than half-worn after those 8 events.

2) With your tire compound, I would choose the Hawk DTC-60. There are comparable pads from other manufacturers. If you choose Hawks, be prepared for copious quantities of brake dust; other mfgr.'s pads will likely produce more or less as much. It's just part of the game.

3) I would look for a fluid with a higher dry boiling point. I ran Castrol SRF, and there are others out there that will give you more headroom than the BMW fluid: e.g., Motul 660. These are quite powerful and heavy cars, so anything you can do to increase your braking system's capacity to withstand heat will serve you in good stead. BTW, the BMW fluid is pretty good; it's just that running hard on a demanding track may well overcome it's capacity to reject heat – and that's the last thing you want to experience at the wrong time.

4) I don't know what's specific to an xDrive model that might affect this. I went to TC Kline Racing for my build and for advice on how to run the car. Two things stood out: a) put the car in Sport+, and then hold down the DSC OFF button to turn DSC off (I didn't know much about the car at the time, and I didn't understand why it was necessary to go into Sport+ mode first – I skipped that step after the first couple of times)); and, b) going into DSC OFF will turn off rev-matching. As an old heel-and-toe guy, I was good with that – until I came to the first braking zone and discovered that, at least on my car, the gas pedal is so far below the brake pedal that my decades-long technique of using the BALL of my foot to do heel-and-toe was useless. I had a choice then: learn a completely unnatural technique for heel-and-toe at 138 MPH, or leave DSC ON and live with the car's propensity for using DSC to "help" me while at the same time slowing me down considerably.

The main thing you're going to want to get comfortable with is the significant weight of the car you're running. In my opinion, our cars' weights dominate everything else. If you've got xDrive, a sunroof, and an automatic, you may well be over two tons out on the track. That is an impressive amount of weight to haul around and to slow. These aren't track cars the way your E46 M3 was - they're altogether different animals.

If your track(s) have hard right-handers, try to keep your fuel level above 1/2; otherwise, you might find the car goes into limp-home mode.