Intake Air Plenum:

The large intake air plenum is designed for the maximum volume required for the S62 engine. Inside the intake plenum, each throttle valve has its own air funnel which is bolted to the individual throttle housing.

The air funnel positions are defined by the shape of the plenum. The funnels for cylinders 1 and 5 face rearward and the remaining funnels face inward.

Fig 1: Identifying Air Funnel

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The lower plenum is sealed to the upper cover by a perimeter gasket and four "o-rings" on the center support towers.

CAUTION: Remove attaching nuts and store away from intake plenum before lifting funnels from the throttle housings so they do not fall into the throttle housings!

Intake Air System: The S62 engine uses eight individual throttle housings that are bolted directly to the cylinder heads. To ensure smooth and stable engine operation all eight throttles must be synchronized for an even distribution of the intake air.

Fig 2: Identifying Throttle Housings

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Electronic Throttle Motor (EDR): All eight throttles are activated by one electric throttle motor (EDR).

The EDR motor is mounted in the "V" of the block and controls the throttles through two linkages. The ECM controls the EDR to open and close the throttle valves.

Fig 3: Identifying Electronic Throttle Motor

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The throttle valves are fitted with mechanical return springs to close them when the EDR is not energized.

Idle Speed Actuator: A separate idle speed actuator (ZWD 5) is used to supply the idle air to all cylinders. The actuator supplies air to the base of the throttle housings which bypasses the throttle valves (plates) to maintain engine idle speed.

Fig 4: Identifying Idle Speed Actuator

Courtesy of BMW OF NORTH AMERICA, INC.

The idle speed actuator is mounted in the "V" of the block and is connected to the throttle valves through large air pipes linked between each throttle housing.