Si Trim Head Unit



While this is our entry level head unit, it is also the most efficient head unit for stock engines in the 500 – 600 RWHP range.  The Si is also the only head unit that can be used in our CARB compliant kits.

Standard Features:

  • Polished
  • V2 – Pressure Lubed from the Engines Oil System – Helical Cut Gears

Gearcase *



The V-2 (ENGINE OILED) and V-3 (SELF-CONTAINED) models, with their highly advanced computer designed gears feature an optimized helical profile which allows for quieter operation while providing superior performance. All V-2 SQ units feature a 3.6:1 internal step-up ratio and are direct bolt-on replacements for our HD V-1 units. The supercharger uses the quieter helical cut gears (3.61:1 ratio). The V2 and V3 Si Supercharger is capable of up to 775HP on modified vehicles. Extraordinary 78% peak efficiency. Ideal for latest generation of improved breathing, high-power street and strip engines.

The new improved Si impeller design provides increased flow and efficiency over earlier designs.

We also have a great “Trade In” program that you should take advantage of when looking to step up to a bigger head unit.

Performance Specs

  • Internal Step-Up Ratio: 3.61:1
  • Max Speed: 52,000 RPM
  • Max Boost: 22 PSI
  • Max Flow: 1,150
  • CFM Max Power: 775
  • HP Peak Efficiency: 78%

Additional information

Weight 19 lbs
Dimensions 12 × 12 × 12 in

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