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Performance Kits

Rotrex Electrically Assisted Variable Speed Superchargers





The patented Rotrex VC8 superchargers combine the Rotrex high speed traction drive with an electric motor, giving for the first time an economical, infinite ratio variable speed supercharger, both highly efficient and with the smallest weight and size, available for 12-48V architecture.

VC8 Technology

Common variable superchargers change their total gear ratio by rearranging mechanical components resulting in a limited gear ratio and often a complex and expensive solution. In contrast, the VC8 has two inputs - one mechanical and one electrical - operating completely independent of each other. The result is a compact and simple drive configuration with infinitely variable gear ratio that can achieve very high impeller speeds, even at zero input pulley speed.

The electric motor assists the impeller speed by driving the planet carrier through a standard type timing belt. With a 12V input, the electric motor alone can spin the impeller up to 130,000rpm in less than 300 milliseconds, thus giving unsurpassed boost response and acceleration time completely independent of the input pulley speed. Upgrading to a 48V architecture further enhances performance of the unit.

The VC8 has effectively no lag!

Suitable applications

The VC8 is intended for the automotive industry as a stand-alone boosting device for heavily downsized engines, or as a pre-booster for larger engines.

An ideal application for the VC8 is on a small heavily downsized petrol engine to improve the bottom end performance, without exceeding the maximum power limit of the engine. The graph on the right is an example of the enhanced performance of such an engine assisted by a VC8. The high bottom end torque is possible due to the VC8’s ability to deliver a pressure ratio of up to 1.5 at idle.

As the VC8 is designed for multiple purposes, the input comes with a universal adaptor that can be used for tra- ditional poly-v pulleys or electrical clutches.

Outstanding total efficiency

The VC8 is based on the unique Rotrex traction drive technology, and the smallest standard Rotrex super- charger, the C8. Furthermore, much effort has been allocated to achieve maximum total efficiency. Even though the VC8 is fully variable, the total power consumption is nearly identical to that of the already highly efficient stan-dard C8 supercharger.

When power is not needed, the VC8 can freewheel at a minimum power loss, or be completely disconnected if equipped with an electrical clutch.

VC8 Key Features

  • High boost at low engine rpm
  • Ideal for single or dual boosting
  • Transient response <300 ms
  • Uniquely small weight and size
  • Low power consumption
  • Voltage range 12-48V
  • “Infinite” gear ratio
  • Ideal for heavily downsized engines

Download the brochure here.




Rotrex - the inventor of the traction drive supercharger