In my efforts to "tame" the engine cooling issue before I fly, I decided to copy a modification I had read about in one of the forum posts which entailed installing a flow divider (for want of a better term) that should help eliminate turbulance at the exit area.
I think a large part of the cooling problems being experienced are a result of the relatively horizontal column of air flowing along the inside of the cowling after passing through the cylinders colliding with the vertical column of air coming down the firewall area from the accessory/oil cooler thereby creating turbulance and reducing the pressure differencial between cold and hot area of the engine (as related to cooling air).
Many builders have added a rounded lip to the edge of the tunnel with some success but I think it is possible to completely smooth out the exit air by installing a divider between the flows (cylinder cooling and accessory cooling air). With this divider, the two columns of air will flow together in the same directs AFTER exiting the engine cowling.
To this end, I installed a piece of 0.025" aluminum clamped to the aft legs of my engine mount leaving a 1" gap at the bottom where the accessory cooling air would exit. I quickly realized I need to modify this a bit as the lower edge of the divider does not terminate below the tunnel opening and I feel that it should. I'll add a lip to correct this.
