About CamPro Engine

The CamPro engine is the first automotive engine developed together with Lotus by the Malaysian carmaker, Proton. The name CamPro is short for Cam Profiling. The engine prototype was first unveiled on 6 October 2000 at the Lotus factory in UK before it debuted in the 2004 Proton Gen 2.

All CamPro engines incorporate drive-by-wire technology (specifically electronic throttle control) for better response, eliminating the need for friction-generating mechanical linkages and cables.


  1. Basic DOHC engine
  2. CamPro CPS and VIM engine
  3. CamPro IAFM engine
  4. CamPro CFE engine
  5. Hybrid CamPro engine
  6. CamPro VVT engine

Basic DOHC CamPro Engine

Campro Basic DOHC engine

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

  1. S4PH (1.6L): 76 mm (3.0 in) x 88 mm (3.5 in), resulting the displacement of 1,598 cc.
  2. S4PE (1.3L): 76 mm (3.0 in) x 73.4 mm (2.9 in), resulting the displacement of 1,332 cc.


  • 2004 - 2008 Proton Gen-2
  • 2006 - 2008 Proton Waja
  • 2006 - Present Proton Satria Neo (Lite & M-Line)
  • 2007 - 2008 Proton Persona

CamPro CPS and VIM Engine

The CamPro CPS engine uses a variable valve lift system (Cam Profile Switching system) and a variable length intake manifold (VIM) to boost maximum power and improve the CPS engine's torque curve over the standard DOHC CamPro engine.

The engine's Variable-length Intake Manifold (VIM) switches between a long intake manifold at low engine speeds and a short intake manifold at higher engine speeds. Proton cars use a longer intake manifold to achieve slower air flow; as it was found that promotes better mixing with fuel. The short intake manifold allows more air in faster. This is beneficial at high RPMs.

The Cam Profile Switching (CPS) system uses a trilobite camshaft to switch between two different cam profiles. One cam profile provides low valve lift, while the other cam profile has a high valve lift. The low valve lift cam profile is used at low to mid engine speeds to maintain idling quality and reduce emissions, while the high lift cam profile is used when the engine is spinning at mid to high engine speeds improve peak horsepower and torque. Unlike the other similar variable valve timing systems such as the Honda VTEC, the Toyota VVT-i and the Mitsubishi MIVEC which use rocker arm locking pins to change the valve timing, the CPS system uses direct-acting tappets with locking pins to change the valve timing and lift profile.

VIM switches from the long to short runner at 4,800 rpm, while the CPS system switches over at 3,800rpm (4,400 rpm in the Proton Satria Neo CPS). The result is 125 bhp (93 kW; 127 PS) at 6,500 rpm and 150 N·m (110 ft·lbf) of torque at 4,500 rpm compared to the non-CPS CamPro's 110 bhp (82 kW; 112 PS) at 6,000 rpm and 148 N·m (109 ft·lbf) of torque at 4,000 rpm. Proton claims that there is better response and torque at low engine speeds of between 2000 - 2500 rpm.


  • 2008 Proton Gen-2 (H-line)
  • 2008 Proton Waja
  • 2009 Proton Satria Neo (H-Line)
  • 2009 Proton Exora
  • 2010 Proton Gen-2 Facelift (M-Line)

Campro CPS Engine

CamPro IAFM engine

The CamPro IAFM (Intake Air-Fuel Module) is essentially a basic DOHC CamPro engine equipped with a variable-length intake manifold, developed under a joint fast track programme that began in April 2005 by EPMB, Bosch and Proton. However, the IAFM differs from the VIM (Variable Inlet Manifold) for the CamPro CPS engine in terms as follows:

  • The IAFM is a stand-alone module that can be fitted with a basic DOHC CamPro engine whereas the VIM needs to work in conjunction with the CPS system in a CamPro CPS engine.
  • The IAFM is operated by the engine vacuum, while the VIM uses an ECU-controlled solenoid.


  • 2008 Proton Saga
  • 2008 Proton Gen-2 (M-line)
  • 2008 Proton Persona (Elegance)

Campro IAFM engine

CamPro CFE engine

The CamPro CFE engine is the light-pressure intercooled turbocharged version of the 1.6-litre CamPro engine, with the maximum boost pressure of 0.75 bar (75 kPa; 10.9 psi). The CFE is the acronym of "Charged Fuel Efficiency".

This is a new market trend of having small displacement engine but forced-aspirated to produce the power output equivalent to a larger motor, a similar concept as the Volkswagen TSI twincharger technology and the Ford EcoBoost engine.


  • 2012 Proton Exora Bold
  • 2012 Proton Preve
  • 2013 Proton Suprima S

CamPro CFE engine in Proton Exora

CamPro CFE engine

Hybrid CamPro Engine

The hybrid power-plant system, which is known as EVE system (Efficient, Viable, Environmental) will be using the same S4PH engine as the one that powers the present gasoline version of the Gen 2, combined together with a 30 kW, 144V electric motor. The main purpose of the hybrid powerplant system is to provide a hybrid system that can be retrofitted to existing models, retaining the same power-plant and also eliminating the need to develop a completely different platform, like the Honda Civic Hybrid. Unlike the IMA (Integrated Motor Assist) technology in the Civic Hybrid that uses a bulky Ni-MH battery pack, the EVE Hybrid system will use a Li-ion battery pack inside the engine bay.

The EVE Hybrid System will have 3 key technologies:

  1. "Micro-hybrid" start-stop system - An integrated starter-alternator system is installed to switch off the engine automatically when the engine stops, for example at a traffic light. The engine will automatically restart when the gas pedal is depressed.
  2. Full parallel hybrid technology - Combines the existing S4PH engine with a 30 kW, 144V electric motor, resulting in higher power (141 bhp combined), higher torque (233 N-m combined), lower emission (up to 22% carbon dioxide reduction) and better fuel economy (up to 4.6 L/100 km). The system also includes regenerative braking system.
  3. Continuously Variable Transmission (CVT) - The CVT system provides an infinite number of gear ratios for better efficiency.

The combined power and torque for the power-plant system are as follows:

  • Max power (gasoline engine only): 110 bhp (82 kW; 112 PS) @ 6,000 rpm
  • Max torque (gasoline engine only): 148 N·m (109 lb·ft) @ 4,000 rpm
  • Max power (combined): 141 bhp (105 kW; 143 PS) @ 5,500 rpm
  • Max torque (combined): 233 N·m (172 lb·ft) @ 1,500rpm (limited to 180 N·m (133 lb·ft) continuous)

Hybrid CamPro Engine

CamPro VVT engine

The CamPro VVT (Variable Valve Timing) is essentially a basic DOHC CamPro engine equipped with a variable-valve timing for more fuel efficiency during low RPM and more power during high RPM, developed for the Proton Iriz.


  • 2014 Proton Iriz

CamPro VVT engine