Smooth Throttle for UpRev

V1H

I see what u mean

And on Wstar's comment that a linear curve wouldn't result in a steady throttle valve opening towards the upper end.. I think I know why that may be. It's a simple trigonometric relation. Opening an almost open butterfly a little further has much less an effect on additional air flow than doing so at a half opened butterfly. Therefore the ECU may have a built-in non-linear interpretation of throttle curve to actual throttle position. If that makes sense.
If all was purely geometric and idealistic this non-linear relation would simply be sinosoidal in shape. Some call this the "S" shape in a throttle map, which is a part of a sine square function. But I wouldn't be surprised Nissan also accounted for other physical parameters (partial pressure, turbulence, etc) which will probably make this non-linear relationship more complex than a simple trig. function.
In order to "reverse engineer" this non-linearity one would really have to play with throttle curves, point by point, until the datalog of the TPS becomes linear with accelerator pedal. That would of course be a huge PITA to do
And on top of that you'd have to repeat everything for all other rpms, coz flow characteristics change with rpm. (No motor has a perfectly flat volumetric efficiency across the rpm range)