Vario Cam Question

[987dds]

At what RPM does the Vario Cam kick in? I had an S2000 and at 6k I got a swift kick in the butt and I knew when the cam profile changed. My car is still in the break-in so I haven't exceeded 4k. Is it a dramatic change?

987dds, here is a good thread that will help answer your question:

4k rpm the sweet spot?

[MNBoxster]

Originally Posted by 987dds

At what RPM does the Vario Cam kick in? I had an S2000 and at 6k I got a swift kick in the butt and I knew when the cam profile changed. My car is still in the break-in so I haven't exceeded 4k. Is it a dramatic change?

Hi,

The VarioCam in your Car is VarioCam Plus, this is a viscous controlled system, rather than the Solenoid Operated one in the 1st Gen VarioCam which is essentially On/Off at specific RPMs. As such, VarioCam Plus is continuously variable through a 40° Range. In addition, VarioCam Plus will also vary the Valve Lift.

While it does do a specific job, due to it's continuous variability, I doubt you will actually feel it. Any noticeable increase in RPM dependent Power is most likely due to changes in Maps (Ignition Timing and Injector changes) by the ECU (DME in Porsche Parlance). VarioCam Plus is mainly to allow for lower emissions and better torque at low RPMs while preserving the Power in the Upper Ranges. Hope this helps...

Happy Motoring!... Jim'99

[Adam]

On mine, I experience a noticable increase in thrust right around 5,200ish rpm accompanied by a more aggressive intake sound. The car seems to run the strongest between that point and 6,200 rpm, after which the tq and hp curves start to taper off slighty near redline territory.

[SD987]

Actually, both Boxster engines are equipped with VarioCam variable valve timing. VarioCam does precisely what its name implies. It varies the timing of the intake camshafts to optimize the performance at any engine speed and load. The camshaft angle is continuously varied by means of twin rotary valve vane adjusters. VarioCam kicks in at 4200 RPMs and peak torque is on tap from 4700 to 6000 RPM.

As well as enhancing power and torque, the system offers smoother running, better fuel economy and lower exhaust emissions. The engine management system identifies current engine requirements, then automatically and seamlessly signals adjustment of the valve timing to match.

The Cayman S and 911 have VarioCam Plus which combines variable valve timing with two-stage lift on the inlet side. The resulting benefits include greater power and torque at all engine speeds, as well as smoother running, better fuel economy and fewer exhaust emissions.

Essentially, the system creates two engines out of one, switching seamlessly between them as driver inputs change. All operations are controlled by the engine management system, which ensures rapid acceleration and smoother running.

The two-stage valve lift mechanism on the inlet side includes a series of electro-hydraulically switchable tappets. Each of the 12 tappets consists of two concentric lifters, which can be locked together by means of a pin at the request of the engine management system. When the tappets are locked, the outermost ring – which is driven by two large-profile cams – is in direct contact with the valve. When the pin is removed, the innermost lifter – operated by a smaller cam lobe – has sole influence over the amount of valve lift. The timing of each valve is controlled by means of an electro-hydraulic rotary vane adjuster at the head of each inlet camshaft.

To improve responsiveness when starting from cold, VarioCam Plus will raise the amount of lift and retard the valve timing. At medium revs and minimal load, the valve lift is lowered and timing advanced to help minimise fuel consumption and emissions.

To achieve maximum power and torque, the lift is raised and the timing advanced.

[Adam]

Since 2003 all boxsters and 911's have been vario-plus equipped so I've read in previous posts. I believe vario plus signifies that the system uses a hydraulic stator rather than the solenoid and it also ditches the chain that drove the old mechanism? Is that right Jim?I know the plus system is infinately adjustable so vario cam is always in effect you could say, but right around 5,200 rpm valve lift must increase significantly as well as timing perhaps because in my experience there is noticably more thrust (almost like a turbo kicking in) and the intake gets much louder. I don't see this change at 4,200 rpm.