The basic Campro engine coded as S4PH is a basic DOCH 16-valve 1.6 L engine that produces 110 bhp (82 kW) @ 6,000 rpm of horsepower and 148 N·m (109 ft·lbf) of torque. This is the engine that powers the Proton Gen-2. The S4PH engine can be fitted with Cam Profile Switching (CPS) and Variable Inlet Manifold (VIM) technology. Besides this 1.6 Litre engine, Proton has produced the 1.3 Litre version of the Campro engine.
Even though the S4PH engine seems to be quite powerful at higher revs, its performance is reportedly sluggish at lower revs and this is proven by driving the Gen-2 uphill where drivers who drive the manual transmission version have to shift a lot between 2nd gear and 3rd gear. This is due to its torque dip in the crucial 2,000 ~ 3,000 rpm operating range, where the torque actually decreases before picking up back to the maximum torque at 4,000 rpm. This torque characteristic can be clearly seen in manufacturer published engine performance curves.
Another engine option for the basic DOHC engine is a 1.3L engine coded as S4PE. The S4PE engine produces 94 bhp (70 kW) @ 6,000 rpm and the torque of 120 N·m (89 ft·lbf) @ 4,000 rpm, which is more powerful than the other 1.3L rivals, even with variable valve timing technology, it also suffers this omission (like its bigger brother) by displaying a torque dip at typical engine 2,000 to 3,000 rpm speeds.
Some Pic Of the Engine bay taken from www.Gen-2.net