Herbie

I know that somewhere, in the throttle area, there is a "Resonance valve", or "Resonance flap" activated by a solenoid. It is also checked by the bosch hammer.
Where is this valve ? How does it works ? I can suppose it is near intake manifold, but I can't find it.

Thanks for any info/pic

SteveW@stig

It is all to do with tuning the intake system, have a read

<a href="http://www.fortunecity.com/silverstone/lancia/58/911/911_1.htm" target="_blank">http://www.fortunecity.com/silverstone/lancia/58/911/911_1.htm</a>

goes in to quite a bit of technical detail.

Herbie

Interesting site, which explains how resonance flap works.

I will know also where is it located and how can it be checked without a Hammer

Thank you

samk

Hi there,
You can check its operation when you turn the key on. You will hear a "click" noise and see it operate. This only tells you the solinoid is working however.
Hope this helps,
Sam

Herbie

Does the solenoid directly move the resonating flap ? I suspect the flap is moved by depressure (if there is enough) that reaches it via the solenoid, if it is activated.

If I correctly understood, behavior is the following: at low rpms solenoid is on, depressure reaches the flap and the flap closes the primary duct, increasing torque.

As rpm increases, in the same way the flap opens the duct, so air mixture can flow more free, and power increases.

I want to check all this system!