djantlive

BMW's valvetronic infinitely adjust (stepless) the intake and exhaust valves to achieve 255hp out of the I-6 in the 330i.

Porsche's variocam plus is not infinitely adjusting the valves right?

I'm Not making a comparison to determine which make's engine is better. Just trying to understand the different technology.

Chads996

It is essentially the same principles. Both create a variable adjustability to allow for optimum air / exhaust flow rates. Each have specific limits. Depending on air conditions, flow rates, fuel octane levels, fuel amount, etc. All of those inputs are fed to the computer and the computer then adjusts the timing, and valvetrain for those conditions. Very cool technology. Not to mention, Saab is playing with variable valve technology WITH a variable compression ratio. That ought to make your noggin hurt.

Chad

snaproll

Variocam Plus in the M96/03 engine (2002+ Carreras) is made up of a conventional camshaft angle variator and switchable two-stage inverted cup tappets providing two different valve lift and opening duration modes.

leedav

Don't tell me...the switchover happens at 3200 RPM, where you feel the little surge?

djantlive

So variocam plus is two stage and not continuously variable. That's what I suspected. Is there any other engine that utilizes continuous variable technology?

johnfm

djantlive: continuosly variable what? Are you referring to valve lift or timing? The lift is two stage: high or low lift. Timing is variable to a certain +- (30deg I think?)

djantlive

Valve lift for intake and exhaust is infinitely variable for valvetronic.

Variocam plus has two stage valve lift.

This is my understanding so far.