Originally Posted by AzNMpower32

It has Dynamic Drive, which sharpens up throttle, and steering. I've experienced it before; the person I rode with hit the Sport button while accelerating in 1st (his was manual), and it shot forward even faster, like a sudden burst of power.

Originally Posted by soldmystang

I64, one fine road.

i actually stumbled upon DS mode today. i might need to read the manual. very interesting.

if i remember correctly, the manual says do not exceed 100 mph or utilize the kick down feature within the first 1500 miles of use. take that for what it is worth. old school theory generally says drive it like you own it in the style you will always drive it. from here on out it is simply, you break you buy it.

Originally Posted by rh71

So I'm seeing 1500 miles for break-in but I've also heard 10k. Which is it?

Originally Posted by HaroldC

Concerning engine brake-in: on all the cars that I've broken the engine in (e39 540i/6, e46 M3, e60 M5) I've always pushed the car, putting the engine through its paces, but never redlining the engine. I've also maximized engine braking, which is what most engine builders will tell you is the best way to break in an engine, resulting in better seated rings, etc. My cars have always dynoed strong, towards the upper range. (these were with stock motors)

So I see no harm in driving in DS mode during break in. Engines that have been pushed, but not abused, tend to be looser and make more power. I have 68k+ miles on the M3 (with a lot of track miles)and it has been supercharged for the last 5k and shows no sign of wear or slowing down. In fact it recently put down 406 rwhp (which I hope will be even higher with the new rev limit).

Concerning gas mileage: yes, running the motor up in revs will burn more gas. No question. On the track my M3 gets ~6mpg and rarely sees anything less than ~5k rpms.

Originally Posted by HaroldC

Enigne braking means leaving the car in gear and allowing the friction of the engine to slow the car down. On an automatic, when you release the gas, the torque converter disengages the transmission from the engine and it offers little resistance to the drivetrain. When you engine brake, (like leaving the trans in DS or manual mode) the transmission and the rest of the drivetrain are still connected to the engine and puts a different stress on the motor and cylinders. This stress has been associated with better seating the rings of the cylinders.

Originally Posted by AzNMpower32

The new 6-speed ATs from BMW do not disengage when you let off the throttle. The torque converter remains locked up and the revs hang, and you get a similar engine braking as you would with a manual.

Originally Posted by HaroldC

The revs still drop, but it might be because the transmission is shifting to a higher gear. Huh. I'd like to get the definitive answer to this, so I'll just ask my friend that works at NA.