VarioCam Plus

[Adam]

There seems to be some confusion on this topic. Earlier posts mentioned 987's had vario-plus. Jim said in an ealier thread that the lift is variable in 987's. The only change I'm aware of is the major one that happened in 2003. Here is some info I found.

Hi,

VarioCam's job is to increase/decrease Valve Overlap to maximize Torque and Power. In the past, selecting a Cam was always a compromize between these two.

By Advancing/Retarding the Valve timing, you can increase Torque, Power, and lessen Emmisions. Retarding the V Timing in the Low-Mid Ranges increases Torque, while Advancing the V Timing at Idle and Low RPM Range increases Power and reduces HC Emissions.

There are 2 versions of VarioCam on the Boxster. Only on the Latter version is the adjustment Continuously Variable.

The 1st version - '97-'02 used an Electric Solenoid which Advances the Intake Cam 13°, the limit of this system is that it is either ON or OFF at a pre-set RPM controlled by the DME.

The 2nd version - '03-'06 eliminates the Solenoids and uses an Oil-filled Stator. This allows for infinitly variable V Timing within a 40° Range. This is where much of the HP/Torque gains are had over previous MY. Also, a Synchronizing chain between pairs of Cams is eliminated probably eliminating a 1-2 HP Parasitic Loss.

Happy Motoring!... Jim'99