Audi V8 Service page 29

Effect of variable intake manifold on torque
500
400
300
200
0
Lower full throttle (stage 1)
Middle full throttle (stage 2)
Upper full throttle (stage 3)
Since the maximum torque across the speed
range depends primarily on the length and
cross section of the intake manifold, the new
three-stage variable intake manifold comes
closest to producing the optimum characteri-
stic torque curve across the speed range.
Depending on the engine speed, appropriate
"resonance tube lengths" are available for the
lower, middle and upper speed range.
1500 3000
3360
Speed
4500 6000
5200
The illustration explains the correlation
between the length/cross section of the
intake manifold and engine speed and shows
the characteristic torque curve produced by
the 3 stages.
7500
SSP217_035
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