Sonic ProStock .21 for Club and Regional Racers


The all-new ProStock .21 on-road engine from Sonic is designed especially for club and regional racers that are looking for a competition engine for a good price. The ProStock.21 is easy to adjust and to handle which helps to focus on driving and setting up the car. Equipped with a five-port sleeve and a CNC machined flat piston, the engine provides great power over the entire RPM range while having a very efficient fuel consumption. The optimised crankcase and knife-edged aerodynamic conrod help even more to reduce turbulence inside the engine. A special turbo combustion chamber with a cooling fin and the lightweight cooling head ensure best heat dispersion to keep the engine temperature at a moderate level. High quality ball bearings and a modern composite valve carburettor with an 8mm aluminium venturi complete this new high competition engine.

• Five-port hard chromed sleeve
• CNC machined flat piston
• Aerodynamic “knife edged” connecting rod
• Turbo combustion chamber with cooling fin
• 14mm high quality main bearing
• 8mm aluminium venturi

Technical data:
• Displacement: 3.49ccm
• Max power: 2.5HP @ 36.000 U/min
• Bore: 16.26mm
• Stroke: 16.80mm
• Front bearing: 7x19x6mm
• Rear bearing: 14×25.4x6mm
• Glowplug: Sonic S7C turbo plug
• Weight: 325g

Source: Shepherd Micro Racing

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