Ahaan! You may be right; your electrician may have found a way to directly connect the speedometer pulse wire to the EPS, bypassing the car ECU. But what I dont certainly agree with is the way you tested this system. With the front wheels off the ground, there's no weight on the front wheels, no rubber friction that inhibits steering, basically nothing for the assist system to do. In fact, if the front of the car is off the ground, you will require very little force to turn the steering wheel, with or without power steering. Its only when the car is on the ground when physics comes into play.
You would appreciate that a variable assist power steering system works between two extremes, maximum assist and zero assist. When you feel it hardening at high speed, it doesnt actually harden anything, only the assist becomes less. When your wheels are off the ground, your steering is soft by default, and the EPS can do nothing to make it hard.
The 'hardening' which you felt while spinning your wheels off-ground is due to the rotational momentum of the CV joints. The faster the joints spin, the more difficult it becomes to alter their path of rotation, which in this case is most frictionless in the linear state. The more you steer, the more resistance the joints will communicate to the steering rod.
In reality, you would never turn the steering wheel more than a few inches while negotiating a curve at high speed. So even if it is heavily assisted, you'll never notice how hard or soft it is while driving at high speeds.
Like i said in my previous post, even without variable assist, this system will work perfectly as it does in the Japanese car. This is my humble opinion. You are free to disagree!
