The Ford VVT is certainly closed loop, which is done by using a 4+1 trigger on the inlet camshaft in comparison to the CPS to measure cam timing position. The actuation system uses pressure to retard timing and a spring return to advance. The soleniod valve feeding oil is fed with a PWM signal by the Blackoak PCM, so in theory 50% duty would give around 30 degrees retard from fully advanced.
Even if your ECU has a spare PWM output and VR input you still need a control algorithm, usually developed or decompiled from a OEM PCM, by the ECU manufacturer.
If you want the OEM (Ford) cam timings then I found them on the Cat Cams website. On the turbo engine I've just finished I've disabled the VVT and gone back to old fashioned DTI and disk to time the inlet cam at full lift. Timing is taken from looking at quite a few fixed cam examples, and still leaves me with adjustment for optimisation with the 'vernier' pulley.
Martin
Last edited by pdfbt40; 29-03-2009 at 11:04 PM.