Basic DOHC engine

The basic Campro engine coded as S4PH is a basic DOHC 16-valve 1.6 L engine that produces 110 bhp (82 kW) @ 6,500 rpm of horsepower and 148 N-m 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 L engine, Proton has produced the 1.3 L 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 uphills 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 between 3,000 ~ 3,500 rpm where the torque decreases slightly before picking up back to the maximum torque at 4,000 rpm.

Before the engine is ready to be installed in the Gen-2 cars, Proton installed the engine in the Waja specialized for on-road tests.

Currently the Campro engines installed in the Gen-2 has none of the promised cam profile switching (CPS) and variable inlet manifold technologies. No date nor any information has been known as to when Proton will equip its models with the promised full-spec engine.

Another engine option for the basic DOHC engine is a 1.3L engine coded as S4PE. While the power output of S4PH engine can't be considered as impressive, the S4PE engine produces 94 bhp (70 kW) @ 6,000 rpm and the torque of 120 N-m @ 4,000 rpm, much more powerful than most 1.3L rivals, even with variable valve timing technology.

The bore x stroke dimensions for both engines are as follows:-

S4PH (1.6L): 76 x 88 mm, resulting the displacement of 1597 cc.
S4PE (1.3L): 76 x 73.4 mm, resulting the displacement of 1332 cc.