Recommended shift points

[SixBanger]

The manual doesn't say, so what are they for daily driving and spirited driving? Car has the PPK performance (just flash) Myles

[SfValley335i]

2000 and 6100

[mike@x-ph.com]

Each car has different shift points you will have to look at your dyno graph and figure out where power starts dropping.

[lo-tek]

Good advice above but really it's kind of simple. Anything over 2k is probably fine; i tend to do about 2.5k if I'm poking around. Torque is solid to about 6k or so.

[SixBanger]

Originally Posted by lo-tek

Good advice above but really it's kind of simple. Anything over 2k is probably fine; i tend to do about 2.5k if I'm poking around. Torque is solid to about 6k or so.

I thought we produced all over our torque at around 1,500 rpms? I know this has changed due to the HPFP failures and changes in the fuel system (DME updates).

[brusk]

Max torque will start somewhere between 2500-3200 and starts to drop off at 4200 depending on mods, fuel and tune. Usually anything over 6200 isn't resulting in any more power than what you would get shifting but at the same time isn't going to hurt anything. I punched in my dyno numbers into a calc at one point and it says 1-2 shift @ 6600, 2-3 @ 6400 and by the time it was 5-6 it was down to like 5800. Good thing is these engines produce good torque anywhere so unless your all out racing somebody it doesn't matter what gear your in just have fun.

[Pyrat 2]

Originally Posted by brusk

Max torque will start somewhere between 2500-3200 and starts to drop off at 4200 depending on mods, fuel and tune. Usually anything over 6200 isn't resulting in any more power than what you would get shifting but at the same time isn't going to hurt anything. I punched in my dyno numbers into a calc at one point and it says 1-2 shift @ 6600, 2-3 @ 6400 and by the time it was 5-6 it was down to like 5800. Good thing is these engines produce good torque anywhere so unless your all out racing somebody it doesn't matter what gear your in just have fun.

Why would the shift points vary between gears? Just wondering... What's the physics behind this?

[New21er]

My DCT (in sport mode) shifts at 4k.

[Pyrat 2]

Really? Depends how hard you are on the gas. Mine is at or close to redline with gas pedal full on. I'd have to look for sure but know that it is nowhere near 4K.

[fe1rx]

Originally Posted by HeelToe

Why would the shift points vary between gears? Just wondering... What's the physics behind this?

The torque at the wheels is what accelerates the car. The transmission and final drive (differential) multiply the engine torque by the product of the two gear ratios.

For a 6MT, the final drive is 3.08 and the respective gear ratios are 4.06, 2.40, 1.58, 1.19, 1.00 and 0.87 giving a "total gearing" in each gear of 12.50 (1st), 7.39, 4.87, 3.67. 3.08 and 2.68.

Multiply the engine torque by the "total gearing" at each rpm and plot it against rpm. Where the plots cross is where the wheel torque in the higher gear equals the wheel torque in the lower gear. Ideally you shift there. The crossing point is different for each gear because there is not an identical percentage change in all adjacent gears.

Then to add a couple of other complicating factors, you don't know the actually engine torque available dynamically. It is not the same as the steady state torque curve that BMW publishes, and it is different in every gear because of a few factors, probably most noteworthy being the power needed for the acceleration of the rotating mass before the transmission (flywheel, crankshaft, etc.) which is different in every gear because the rate of engine acceleration is different in every gear. The rotating mass after the transmission has the same effect in every gear.

You can assume the basic torque curve is constant and ignore rotating mass and get an answer but it will overestimate the shift point in 1st and 2nd in particular.

A data log with an accelerometer would be definitive, but who really cares that much?

All that said, 2100 and 6100 (or somewhere in between) is pretty good advice. But it is an art really, not a science. Revving when you don't need to and lugging when you should be revving are both signs of a lack of sophistication (to put it politely), but the engine is so tractable it will happily shift anywhere.