IIRC there has been discussion here of wheel rims which would "pump" air outwards, reducing pressure under the car.
The reduced pressure would have to fight the suspension springs, and the outcome of the discussion seemed to be that the increased pumping losses outweighed any benefit from potentially reduced underside aero drag and/or temporary lowering of the car (assuming the suspension gave in).
Given this outcome, these rotor/fans might lean towards the
unaerodymic thread.
Anyway, these do not work well with smooth moonies, so, yeah.
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e·co·mod·ding: the art of turning vehicles into what they should be
What matters is
where you're going, not
how fast.
"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell
[Old] Piwoslaw's Peugeot 307sw modding thread