Originally Posted by
Cani Lupine
The separation isn't caused by too steep of an angle, so VGs will only increase drag. If you want to eliminate that separation, try taping up the gap between the roof and the hatch. It's actually quite a large gap. I'm sure the flow remains smooth above the boundary layer, though. If someone has a GoPro, I'd like to see someone do a tuft test to prove my theory, with and without taping the gap.
Also, the VGs aided the Mitsubishi Lancer Evo's spoiler because it's technically a wing, not a spoiler, and the VGs increased the airflow over the whole unit (top and bottom sides). Our spoiler is nothing more than a roofline extension, and the air underneath it is the wake.
I agree wholeheartedly on this. I haven't crawled umder the vehicle to look but I think you could gain much greater decrease in drag by installing panels underneath the car to smooth out the underside. Lots of air resistance underneath a vehicle because of it's irregular shape.
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