ORIGINAL: MustangAce
If the cowling was not cut out, would NOT having the louvers installed cause overheating??? DA-50 stock muffler???
It all depends. If you left the baffle out you will get plenty of air into the cowl that can exit out through the oil pan. The problem is this. With that big 12" opening in the front of the cowl, you don't get air "forced" directly over the motor with no baffling, instead is just enters and swirls around. The whole point in the baffle is to force air directly over the fins on the motor then out the bottom of the cowl and in my case or those who have a pipe installed; air is also forced out the tunnel area as well. By having the air forced directly over the fins and out the bottom of the cowl there is no need whatsoever to open up the cowl at all.
To test this is simple. Fly the plane with no baffle and nothing else done to the cowl, land and check the temp of the motor, mine sits around 160-175. If your motor runs hot then you will want to install the baffle. Install the baffle and don't open the bottom of the cowl, land it and check the temp, if its not running hot then you are set and have no reason to butcher the cowl up. Remember you can always trim later, but you can't put back what you already took off.