What is AMAX?

[ryanlada]

I see AMAX referenced multiple times in multiple posts but can't seem to find a post that says what it is, can someone help me out here?

[DGVR6]

I think this is good enough

Amax uses both clutches simultaneously and slips between the gears.

A normal shift de-rates the engine by telling the ECU to pull timing. It does this to prevent free-revving and to lower the torque at the clutch to make shifting easier. It has the engine de-rate while it's opening the first clutch. The engine free-wheels for 50ms or so while the second one is being closed and then the TCU tells the engine to bring back the power. That de-rate timing retard is what causes the DSG "farts" you can hear on videos.

Amax doesn't work like that. When in this mode, the TCU keeps the beans on the entire time. There is no de-rate at all. It controls the engine RPM by having both clutches engaged in the linear (slip) region together while it transitions between the two. The upshot of this is that there is no de-rate, the engine is making full power the entire time and is transmitting it to the ground even during the shift. The downside is that it's extremely delicate. If the transition time is too fast, the clutches won't slip enough, will be working against each other and will rip themselves out of the transmission. On the other side, if the transition time is too slow, the engine will free rev, hit the limiter and de-rate via the rev limiter. It comes back as soon as the clutch closes a bit more and pulls it off the redline, but it still spent some time in de-rate.

[ryanlada]

This applies to DSG and ZF transmissions?

[Alister]

Based on the above description including 2 clutches, no, DSG only.

[DGVR6]

ZF would be the same concept I'd imagine, no derate in amax mode. Power is kept in between shifts

[limeypride]

I think this is good enough

That's a great description for the DSG but I'm not sure how to translate that to the ZF 8-speed. It doesn't have a single clutch, let alone 2. I'd be interested to hear such a description for the ZF because, however it works, it makes a huge difference (and oh how I wish it would shift like that whenever the car is driven aggressively but alas...)

[Chris Morales]

Whatever the details, the gist I think is that normally the TCU tells the ECU to pull timing and power between shifts in order to preserve the transmission, but AMAX mode turns that protection off. You power straight through the gears.


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