Originally Posted by fdb
Mazda's system continuosly varies valve timing, but does NOTHING to lift and duration of the cam. Those are constant.
The latest version of VTEC, found in the RSX, varies timing continuosly like Mazda's system and still switches cam lobes at 6000rpm or whatever it is.....
Correct Honda's is still more advanced interms of internal engine timming controling with its cam profiles. However Mazda has along with their static cam shaft that does kick its timming at 4500rpm, is VAD (Varible Air Duct) VLIM (Varible Length Intake Manifold) VTCS (Varible Tumble Control System) VVT (Varible Intake Valve Timming ( Cam-phasing intake cam only). These are all addition ways to give control to the static VVT. Our VVT is more benificial then Hondas in the sence that it give us more torque at a more brodem RPM range, but not controlled. The control comes in to play wth the others mentioned above.
So in essence instead what Mazda has done was realize that the controling cam while timmimg is not going to acheive the best power gains in terms of torque. They decided to let put controled valves in the intake runners and Air ducts of the air intake system. This give the flexiblity lost with none controled cams but the added full torque with the static VVT.
his is another form of valve tuning, and it works on the principles of Helmholtz Resonance. This was created in the 1991 Mazda 787B Rotory car that was banned. It was the first rotory & Japanese car to win the Lemans 24hr race.