Variocam+ Cam Switching

[tholyoak]

Does anyone know when the solenoid valves for the cam timing and cam profile (lift) are actuated on Variocam plus? Is the solenoid activated by the DME to provide late or early timing? I am pretty sure that the solenoid for valve lift is actuated to change from the low to high lift cam profle but again I am not certain.

Thanks

Todd

[Loren]

Todd,

I think you will find your answers here.

[tholyoak]

Loren,

Interesting information, but it does not contain the information I was looking for,

Thanks

Todd

[Richard Hamilton]

Here is a quote from the 2002 SIT for the C2:

"The camshaft adjuster is based on theprinciple of a vane cell adjuster. The control unit determines the current position of thecamshaft in relation to the crankshaft (actual angle) using the engine speed and hall sensor signal. The position control in the control unit receives the desired angle via the programmed map values (engine speed, load, engine temperature). If the desired angle and actual angle differ, a controller in the Motronic actuates the 4-way proportioning valve to the desired position."

I don't know if this is the kind of information you are looking for, but you can download the complete article from here:

https://techinfo.porsche.com/techinfo/sit/e.../1_2002_911.pdf

Alternatively, go to: https://techinfo.porsche.com/techinfo/index.jsp

and select Great Britain (not USA)/Training Documents, and select 911

[tholyoak]

Thanks I think the info I am looking for is in the pdf you posted. I understand how variocam works,(there is a great description in Paul Frere's 'Porsche 911 Story'). I just want to know when the solenoid is activated by the DME, does the cam timing advance or retard. Same with the valve lift. I am assuming that the timing is late and the valve lift low, when the solenoids are not activated (since this is the condition at idle and low loads and a peg holds the cam rotor in the late timing until oil pressure builds), but I would like some conformation of this fact.

Todd

Edited April 8, 2007 by tholyoak