Here is a little from someone who actually dynoed a qs138 90h (so the 70h will saturate earlier)

It seems the 90h starts saturating at 800A, but still gives pretty good extra torque at 900A, and higher voltage should help with extra rpm :

QS 138 90h V3 - verification of parameters and limits

I have prepared some facts regarding this motor, based on laboratory measurements on the motor dynamometer and several years of experience working with it. The most important information to consider when designing your motorcycle:

- The maximum power at the motor shaft that I achieved is 40HP.

The supply voltage under load at this maximum power is 87.6V - a highly efficient li-ion source 24s, measured at the controller terminals.

It is IMPOSSIBLE to achieve greater power at the motor output based on a pack with a nominal voltage of 72V (20s), regardless of the controller used.

I achieved this power with a maximum efficiency of 86%, resulting in a source power of 34kW.

- The maximum phase current during tests is 460ARMS (800A), allowing for a maximum torque of 80Nm.

This is the recommended current limit; higher current significantly changes the value of the torque constant Kt [Nm/A], and additional current has little effect on torque increase (600Arms generates 100Nm).

- The rotational speed for this maximum power is 5010rpm, much higher than the rated speed of the motor.

Increasing losses start to have a greater impact on total losses, particularly losses related to the frequency of stator magnetization (eddy current losses and hysteresis losses). Powering the motor above 24s (100.8V) is economically unjustifiable; the power losses alone amount to several hundred watts converted into heat.