Another test for the air scoop is to see if boost onset is changed between having the scoop installed and the opening covered.
For this test the GTI is driven in third gear and the accelerator pressed fully to a pedal position of 100 from a start of 0 input angle. This pedal position is held while the intake manifold boost pressure increases to just over 20 psi.
The test is conducted with the air scoop open, shown with red lines in the chart below, and the air scoop opening covered, shown by the blue lines.
Measured this way there does not appear to be a change in boost onset resulting from the air scoop.
The data was evaluated in another way, measuring the time that passes from boost pressure reaching 1 psi until it reaches 20 psi. This boost onset time is graphed versus the engine speed when 1 psi is reached. The next chart also shows the air scoop “open” data with red dots, and the scoop opening covered with dark dots.
The conclusion is the same, there is no discernible difference in boost onset time between the two test conditions.