One builder on the RV list said he got a big improvement in cooling by installing VGs on the trailing edge of the cooling outlet.  This is so non-intuitive that I can't imagine why it would work but its so easy to try I might have to do it while scratching my head.

Tracy

 

Vortex generators generate vortexes. Spinning part of the airflow causing it to travel a greater distance in the same time as surounding flow, So, higher velocity, So, lower pressure (Bernoulli). The pressure differential between the inside of the cowl and the exit is increased.

 

Lynn E. Hanover