The air flow through the engine bay is designed to be from the side vents upwards

& exiting the vents in the engine cover, introducing another airflow in the opposite direction will have a negative effect.

you'll slow the intake rate at the side vents.

If you baffle around whatever induction filter you are running

& isolate it from the engine bay air you may benefit a NA car but I can't see it making any difference to a turbo.

I can see a tsunami of rain getting down them so don't forget to allow drainage.

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