[Hotshot8792]

actually, the N/A DOHC car has something similar to Vtec already on the car. The intake manifold consists of these butterflies that are controlled by the ECU. Notice that the back of the intake manifold is curved, which is basically a second path. When your car is running low rpm's, it closes the short route, causing your air to go through the longer route increasing your torque. Then, as your rpm's increase, it moves and closes off the long route allowing the air to travel the short route giving you top end. Pretty much the same thing as vtec, just doesnt mess with your cam timing. The reason they did not put these on the VR-4s is cause the small turbos spool up quick enough to give the low end torque without it, but, a lot of VR-4 owners have been trying to figure a way out to run the N/A DOHC intake manifold on their car, its just hard to figure out how to get it to work with the ECU since it has to be hooked up to it.