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To capture what was happening, I used the trusty ole Replay XD0180.
I used some weird Photoshop color hue adjustment function to make the tufts stand out better. The top picture is while the car is sitting still. The bottom picture is with the car at speed. The easiest tuft to use for visualization is probably the one taped to the underside of the flap on the left. As you can see when the car is sitting still, the tuft is just lying there. When the car is in motion, it’s pushed upward. You can also just make out the central tuft on the underside also getting pushed upward by the air exiting the vent. This occurred at about 45mph.
This is the side vent with the car stationary in the top picture and in motion in the bottom picture. For some reason, the last tuft stood up all on its own while the car was stationary. Maybe it ate a small blue pill before testing. With the car in motion, it’s most obvious on the back two vents how the tufts were blown out of the vents. Remember, the tufts were lying sideways when the car was stationary.
I moved the tufts that had been sitting on the back edge of the holes to the underside of the flaps to try to get a different visualization.
On the second and fourth openings, you can see how the tufts attached to the backside of the flaps were still pushed upwards. On the first and third openings, the tufts are pushed so that they are bowed outward, but I made them too long and they caught on the back edge of the openings.
This image was from back in the day when I tested out the Fluke thermal imager. Notice the driver’s side of the hood is warmer than the passenger side in the front half of the hood. Further back on the hood, the passenger side appears hotter which is likely due to the exhaust manifold.
