Optimal Acceleration: Speed & RPM Explained

I've noticed that most automatic diesel transmissions only shift at around 4500 rpm when using the kickdown function. Wouldn't it be better for optimal acceleration (0 to 100 km/h) if they shifted closer to 4000 rpm? Shouldn't you shift when peak torque is reached? What are your thoughts on this?

Below the rated speed, acceleration performance decreases again, but connecting to the next gear is naturally better if you enter with a higher RPM. Ultimately, it's about optimizing the power integral, and for that reason, the automatic transmission rightly goes beyond the rated speed in certain situations. It doesn't make sense to shift to the next gear as long as the power in the current gear is still higher than the power in the next gear.

That's probably the theory, but subjectively, I find that the acceleration feels greater and more pleasant with less noise than with the roar of a diesel engine.

Greetings, Klaus.

Okay, so a roaring ALH engine definitely has something special about it .

However, it's true that, especially for the ALH engine, shifting should ideally occur at or around 4000 rpm, although a shift point of 3800 rpm would also be appropriate in other situations.

VAG simply cannot or does not want to write reasonable automation software.

The program in the AG4 department is so weak that even apprentices would do a better job.
(Does anyone know of a service provider who can modify the software?)

Sure, here is the translation of the text from German to English:

'examples:'
- The turbocharger coupling opens unnecessarily often, instead of utilizing the TDI's torque.
'For example, at 80 km/h and 1800 rpm, when I give it more than 60% throttle... it's completely ridiculous. If the fuel injection was set to 100%, that would be perfect.'
- Downshifting (to first gear) when quickly pressing the accelerator. And this at 130 km/h! It's worth mentioning that 130 km/h in third gear is 4100 rpm, and the kickdown was NOT engaged...
- Torque converter unlocked at 50 km/h (1600 rpm).
- The clutch disengages very slowly, especially when full throttle is applied (the rubber band effect...).

'Sometimes, the software unexpectedly closes the throttle (WK - 'Wollzahl', likely referring to a throttle control setting) in the last tight curve before the town sign, even when you're giving it full throttle. Then, with the throttle closed, it stays like that until you reach fourth gear, and then the engine roars (shifts at around 4000 RPM).'



CU Gremlin.