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Old 12-12-2017, 05:36 AM   #13
78F350
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Location: Oklahoma
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A bit of a side discussion... In very simple terms a resonator (that extra appendage looks like an extra resonator) increases the volume of air in the intake tube without making it flow farther. In doing so it acts as a buffer for the vacuum.
In more precise language:
https://itstillruns.com/air-intake-resonator-do-12156112.html

Deeper still is the discussion of intake runner length. A few years ago I was swapping an SUV engine into a small car and noted the SUV had a much longer intake. In simple terms, length mainly effects where the torque peaks in the power curve. Longer tubes make the torque peak sooner:
https://mechanics.stackexchange.com/questions/25236/how-does-intake-manifold-runner-length-effect-the-power-curve-of-a-car

Then there's the 2000 and later M96 engines with the cross tube and resonance flap that can spread the torque peak across a wider range:
Quote:
Originally Posted by 78F350 View Post
...
Quoted from: http://press.porsche.com/archive/products/press_kits/press_kits_2001/PDF/Boxster_in_Depth.pdf

"The Boxster inherits its twin-resonance air induction system from the 911
Carrera. The system acts as a “resonance supercharger,” allowing the engine
to draw from higher velocity airflow at certain engine speeds. A crossover pipe
connects the individual air collector/resonance chambers for each cylinder bank.
A flap in the pipe remains closed from idle to about 3,100 rpm. When it opens,
each cylinder bank can draw from airflow “excited” by the resonance created by
alternating induction between all six cylinders. In essence, “dual resonance”
creates two induction paths for each cylinder. Below 3,000 rpm, the cylinders
draw air from a “short” path. From 3,000 rpm to about 5,100 rpm – when the
resonance flap opens – the cylinders draw from a long intake path, which
boosts torque. Above 5,100 rpm, the flap again closes to allow the cylinders
to draw intake air from a shorter intake path to boost horsepower at higher
engine speeds."
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Last edited by 78F350; 12-12-2017 at 05:38 AM.
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