VarioRam

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VarioRam is a Porsche-patented engine induction system that was first introduced on the 1992 model year 964 Carrera RS motor sport special, and became standard on the 911-series engines from the model year 1996.

As the name suggests, VarioRam varies the effective length of the inlet ducting depending upon engine load and speed. A long intake length at low rpm provides high intake air velocity, which aids low-end torque. At higher engine rpm, the intake length is reduced. The result is a flatter torque curve, with more torque available at low- and mid-range engine speeds compared to a similar non-VarioRam engine.