i quote Isaac
The new 180hp Celica GTS (USA/CAN) now features the amazing VVTL-i engine developed by Toyota and Yamaha. Based on the standard 140hp 1.8 VVT-i, the VVTL-i has both Variable Valve Timing and Variable Valve Lift. The latter is achieved by an extra cam lobe that is brought into play by the engine electronics via a hydraulic actuator.
Interestingly, Toyota have set up the system so that the extra power kicks in over 5000 rpm. The torque curve of a VVTL-i is almost exactly the same as a VVT-i up to that point and then suddenly, where the VVT-i begins to run out of steam and revs, the new engine develops a new lease of life producing the extra 49 bhp right through to its 8000 rpm redline.
The diagram below shows the two cams which are both always turning, and the hydraulic actuator that moves the 'Rocker Arm Pin' into place at a preset engine speed."