Proton Gen-2 - Performance

Performance

Proton owns Lotus Cars that was involved in the development of the car. The Gen-2 is the first Proton model to use the new Proton/Lotus developed Campro engine. Although the Gen-2's S4PH 1.6-litre engine delivers a claimed 0–100 km/h time of 11.2 seconds (manual transmission) and a contemporary maximum power output of 110 PS (81 kW; 108 hp) at 6000rpm, it suffers from poor mid-range torque.

This is due to a torque dip in the crucial 2,000 - 3,000rpm operating range, where the torque output decreases slightly before picking up back to its peak torque, which is delivered at 4,000rpm. This torque characteristic can clearly be seen in manufacturer published engine performance curves and is widely attributed to the missing Camshaft Profiling System (CPS) technical feature that the engine was named after, but which did not make production, to save costs.

The original (non-CPS) Gen-2's ECU's Engine and Automatic Transmission mapping has been modified several times since the car's launch to improve perceived mid-range pick-up, but the upgrades did not markedly improve the cars' driveability.

This undesirable torque dip was eventually corrected by Proton in 2008 with the introduction of the "new" CamPro engine, designated CamPro CPS, which finally delivered camshaft profiling (variable valve timing) as part of the engine specification.