Like the rose, a variable length intake manifold by any other name would still increase horsepower and torque. Toyota’s name for this technological rose, and the system used in all three Tundra engine options, is Acoustically Controlled Induction System. In the simplest terms, the ACIS supplies a blast of air, like a tiny supercharger, into the combustion chamber under specific driving conditions. How sweet.
Here’s a cutaway of the 5.7 V8. Note the tag for ACIS in the upper right hand corner.