Om642 swirl flap poaition

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IFFY100

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Jun 8, 2020
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Location
SCOTLAND
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Cls 350 cdi 2010 grand edition
Just a quick one - took the intake manifold off and renewed the arms and motor. Can I just check, are the swirl flaps meant to be in the fully open position when motor is refitted? Thanks.
 
motor spring push them open, so open at rest
 
On the subject of OM642 Swirl flap motor ( if specific to Mercedes CLS or W211) is the position of swirl flaps on idle or when the engine switched off (as looking from the front of a car) the left arm towards you and the right away from you? I have attached an image to illustrate it. Thanks!!

P.S. As I understand, by raving an engine the flaps starting to move, opening inlets for more air into manifolds.
 

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I don't think it fundamentally changes the volume of air to be delivered to the engine, or more correctly, the swirl flaps by opening and closing don't in themselves act as the limiting factor in delivering air into the engine.

At low air (flow) requirement (low load/revs), the air is moving slowly, and so the closed (partially closed) flaps help to introduction turbulence to that slow moving air to improve fuel-air mixing before combustion. At higher revs/air flow speed, the air is naturally more turbulent and the flaps open so that they don't impede air delivery to the engine. The speed and and therefore inherent turbulence with the faster moving air results in optimum fuel-air mixing.

This is why when doing the 'resistor mod' to electronically 'delete' the swirl flap motor, you disconnect the arm to the flaps and fix it in the open position (because if it was left in the closed position, the closed flaps could become the limiting factor in delivering sufficient air to the engine under high air demand conditions).

*I think
 

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