Two-Stage Intake
08-11-2009, 01:14 AM
#1
3rd Gear
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Two-Stage Intake
I have a 2003 996 Carrera2 with the 6 speed transmission. My previous car was a 1990 964; which, when it reached 5,500 rpm had a definite growl and increase in power to the redline as the secondary intake opened.The new car has much better power, especially thru midrange, but it is also supposed to have a 2 stage intake. How can I tell if the two stage intake is working properly and where is the valve specifically located in the intake manifold?
08-11-2009, 08:45 AM
#3
Race Car
An intake air system divided by a tuning flap permits the oscillations of the intake air column to be exploited over a large engine speed range (resonance supercharging).
During this process, the different power strokes mean that air is sucked up between the cylinders from both reservoirs of the intake air system in alternation. This alternating suction excites the air mass in the intake air system. During resonance, the intake frequency of a cylinder bank corresponds with the natural frequency of compressive oscillations in the associated reservoir. The natural frequency is determined by the geometry of the intake manifolds, resonance pipes and reservoirs. A decisive factor, however, is the overall length of the pipes from one intake cylinder to the next, the different lengths of intake and resonance pipe sections and the depth of the reservoir in the direction of flow.
The DME control module activates a changeover valve which opens and shuts the tuning flap through vacuum. The tuning flap is open without flow, but is actuated and closed each time the ignition is switched on. Once the engine reaches the programmed idle speed after start-up, the tuning flap is opened once more.
Switching points of the tuning flap:
Tuning flap not actuated from 700 to 3120 rpm and from 5120 rpm .
Tuning flap actuated from 3120 to 5120 rpm , if the throttle is also more than 30 % open at the same time.
During this process, the different power strokes mean that air is sucked up between the cylinders from both reservoirs of the intake air system in alternation. This alternating suction excites the air mass in the intake air system. During resonance, the intake frequency of a cylinder bank corresponds with the natural frequency of compressive oscillations in the associated reservoir. The natural frequency is determined by the geometry of the intake manifolds, resonance pipes and reservoirs. A decisive factor, however, is the overall length of the pipes from one intake cylinder to the next, the different lengths of intake and resonance pipe sections and the depth of the reservoir in the direction of flow.
The DME control module activates a changeover valve which opens and shuts the tuning flap through vacuum. The tuning flap is open without flow, but is actuated and closed each time the ignition is switched on. Once the engine reaches the programmed idle speed after start-up, the tuning flap is opened once more.
Switching points of the tuning flap:
Tuning flap not actuated from 700 to 3120 rpm and from 5120 rpm .
Tuning flap actuated from 3120 to 5120 rpm , if the throttle is also more than 30 % open at the same time.
08-11-2009, 11:54 PM
#6
Rennlist Member
