"Then one of guys at the airport, who's opinion I greatly respect, convinced me to make an "air grabber" of sorts, and force the air into a plenum in front of the oil cooler."
This is the best way to go. Granted it may not be the easiest. The "feeder" duct does not have to be round. A flat but wide duct can supply the same amount of air. If your space is very restricted you could even use two ducts half the height as one and merge them into the plenum prior to the cooler. These ducts could be fabricated into the inside top of the cowling. The location of the inlet is the critical thing. From the centerline of the spinner and lower will give the best results. You could even partition off part of the normal cooling air inlets and plumb this air to the cooler. If you put the inlet any higher or on top of the cowling you could get reverse air flow at high angles of attack like climb out when you need the cooling most. Stephen Teate Paradise, Texas
