Russell Duffy wrote:

Has anyone here put their radiator and oil cooler at the air exit of the cowl?  .... This would be the absolute simplest solution to my problems, if it works.  ...  has two beautiful 24 sq in ... The radiator and oil cooler could be moved ... The cowl cheeks could be closed up ...
I think you need to know what the stuff you already have is doing.  What exactly is the pressure drop across your radiators?  Your oil coolers?  If you know, I missed that part of the discussion.  It takes 4" - 5" H2O to get any performance out of a radiator.  3" is a compromised, non-performing system.  You can do it with a dirt simple manomerer terminating just upstream and just downstream of the radiator.  If not a manometer, hook those hoses to an airspeed indicator (you'll want about 100 kts pressure drop across any heat exchanger).
 Now of course the problem is the engine and turbo heating the air prior to having it get to the oil cooler, then radiator.  I just have no idea how much it would be heated though.  Can anyone take a swag about how much of a problem this would be?  ...  I REALLY could use the new... you-know-what to measure some temps.  ... measure the air coming out of the back of the radiator/oil cooler ... out of the cowl ...
Doesn't Home Depot or Wal-Mart or Harriet Carter or someone have little inside outside temp senders for about eight bucks?

... give me some idea how much heat is getting added ....
What if you went to Wick's or ACS and got some of that asbestos(?) tape and wrap your exhaust, turbo, etc. and then wrap a layer of heavy Al foil on top of that?  I did that to my EZ once and it helped a LOT with the cooling air going over the exhaust on it's way to the cylinder fins.  Might have negative long term consequences (like you can't see cracks forming, etc.) but it might get you past some near term obstacles.
 They claim that my plane is loud, and annoying,
Screw them !!  And the horse they rode in on !!

Just a theory .... Jim S.