Lotus Elise Service Notes page 546

Lotus Service Notes 340 H
Intake System & Resonator Valve:
A new short intake manifold assembly incorporates individual inlet tract
butterfly throttles operated via cable quadrant between cylinders 2 & 3. A carbon fibre airbox, bigger still than
the Sport 190 version, is supplied with air via large diameter trunking terminating at the left hand lower corner
of the engine bay. Incorporated in the intake trunking at the entrance to the airbox, is a butterfly valve which is
controlled by the engine management system, and is designed to suppress resonant intake noise under certain
engine operating conditions. The valve is sprung open and is closed by a vacuum actuator supplied via a pair
of solenoid valves mounted on the LH side of the engine bay. The solenoid valves are controlled by the engine
management ECM which is programmed to close the valve when accelerating with wide throttle through the
lower gears at about 30 - 40mph.
The flap capsule is connected to a vacuum charging solenoid valve which either ventilates the the capsule, or
connects it to a vacuum locking solenoid valve. The locking valve either seals the charging valve, or connects
with the manifold vacuum supply via a reservoir mounted on the roll over bar back stay.
MAP sensor
Inlet tracts
Page 13