German Car Zone

Still don't know why it's not faster at the straight line as the old SL55...

The figures from the SL63 is a bit disappointing, it is slower than the SLK in the slalom and the warm braking distance is the same for both cars.

The SL55 has a more favorable torque curve for acceleration.

But the SL63 has a quicker gearbox. Maybe it has something ti do with the gear ratios?

Shorter gear ratios, launch control... and it's a bit lighter than the SL55...

True, but low end torque has an upper hand. The SL55 delivers more toque than the SL63 and at a lower rpm making it a whole lost faster in acceleration.

SL55: 720Nm @ 2750rpm
SL63: 630Nm @ 5200rpm

But at full acceleration low end torque is not an advantage, because the engine always run at higher rpm. For example when the SL63's automatic shifts up at 7200 rpm, the rev never goes under 5000...

It is, especially if you accelerate from a standstill. While a SL63 would have to be revved up to 5200rpm an SL55 would already be taking off at 2750rpm where they full torque is already deployed. That's two advantages. More torque AND at a lower rpm.

Massive low end torque is one of the reasons why the cars like the 997TT is fast like a rocket. 680Nm at a mere 1500rpm.

That's true, but after they shifts up to 2nd gear they only rev at higher rpms, so low end torque must be an advantage at launches and not at high-speed acceleration. So I still can't find the reason, the SL63 should be much faster than 15,6 s up to 200. (AutoBild did 13,4 s with the last, 517 hp SL55 two years ago )

Yes it only aids in launches and by the time both cars hit the second gear the SL55 would already be riding at a higher velocity thanks to the head start given by the torque.