The intake manifold flaps may be more commonly known as "Tumble" flaps in M-B vernacular..... by "Swirl" flaps in BMW language...... and simply as "Intake Manifold Flaps" in the Audi world.
All three German manufacturers incorporated the Swirl flap design in their engines to increase the turbulence of the air/fuel mixture entering the intake manifold at low RPMs, hoping to gain better combustion efficiency and reduced emissions at low speeds. :wink
Swirl flaps are more effective for diesel engines than gasoline, as diesels do not have throttles plates to regulate the air/fuel mix.... and so naturally tend to run between lean and rich conditions wildly, because throttle is controlled solely by the fuel injection on diesels.
Typically on a diesel engine the Swirl flaps are designed to function in the following range:
1) Closed at low engine speeds and low injection volumes (map-controlled)
2) Open when:
• the coolant temperature < 14 °C, or
• the amount of fuel > 24 mg, or
• engine speed > 2250 rpm, or
• the intake temperature < -5 °C
If the Swirl flaps are either removed, or left in the OPEN Position, performance change will be minimal and probably no difference will be noticed. Furthermore, the car will still pass an MOT and drive as normal. :grin
IMHO, if you own a MB gasoline engine with Swirl flaps, leaving the flaps in the Open position and using your $1 resistor solution is a proper and effective solution.
All the German manufacturers have retreated from using the Swirl flap technology, as it was more of a PITA, and a danger to the engine, than it was as an effective low-RPM emissions enhancer. :eek
So, while you may take some heat from purists, you are certainly not alone.
Many MB, BMW, and Audi owners are doing what you have posted. :goojob:
Take Care, and May God Bless, Arctic