TVIS

Authored by: Nepherim

4A-GE engines have a TVIS intake system. Each cylinder in the engine has two intake runners going to it. There is a valve that is controlled by RPM that opens the second set of runners at approximately 4300 RPM. This was done so that at low rpms, the engine would breathe through one long runner to increase torque, while at 4300 RPMs, to increase high end HP, the TVIS valve opens up to increase engine breathing.

This system is very similar to the one used in the Acura NSX. Later incarnations of the 4A-GE (post AW11) however, dropped this option, as a single small port was used to increase velocity of the air entering the engine.