what is variable gear ratio steering steering system?

Variable ratio (VR) steering means that the ratio between the steering wheel and the wheels (tires) is not constant. Depending on the position of the steering wheel the car wheels may be more or less sensitive to steering wheel rotation. Practically, when you drive straight (steering wheels in neutral position) the steering ratio is about 2 times higher compare to steering ration when you are parking (steering wheels is away from neutral position). Variable ratio rack and pinion is used in VR steering. It was originally invented in Australia and later improved in the USA. Variable ratio rack and pinion software is used for calculation of the complex tooth surface of the vr rack.

Most steering boxes are now variable ratio.

It is a device which both makes your steering wheel's output, "the pinion" connect with the "rack", a device which affects your front wheels forward angle. It also controls the ratio of steering wheel input to actual steering output.

High performance cars will have a relatively low ratio steering ratio, meaning minor steering wheel input will dramatically affect steering output while ordinary passenger vehicles will have higher ratios requiring more steering wheel input to produce a similar amount of vehicle steering.

i believe it is 16:1