I'm not the only one but there are a couple of us. Jeff Perdue had to move his oil cooler away form the stacked config and as soon as he his temps dropped 40deg. There are a couple of things the could be affecting my sistuation. I am running fuel injection so I'm probabyl not as rich as you guys and I'm make 5% power. Not a huge thing but it might contribute. I also have my intercooler which is shooting air into the top of the cowl and like Dustin said, it may be over whelming my exit negative pressure. I may try to tape one off one of the NACA ducts and see what happens to my temps. I would have to fly with a lap top to watch my TCU show my manifold temps. So far I've never seen the waste gate open so maybe I can get a smaller intercooler that needs less air.

To respond to Dustin, it's funny you mention the Lo presti cowl because I want to at least modify Natalie's cowl to have protruding circles instead of the current setup because from those circles you can fair into the cowl and keep the air laminar easier which is definitely not happening on the current set up with that sharp ridge. I envision one intake being used for the plenum I want to make, the other for general cooling air. I think like you said, if you can direct all that swirling draggy air, it will probably have better flow and have better velocity. I may do this to mine too if it works well for her. I just loathe the idea of changing my cowl dramitcally on a flying plane. I do think the Model 6 FWF had a better design in a lot of ways. All the air going under the cowl HAS to go through the rad so it's getting loads of high pressure air. However, the Delta T isn't as good as it can be because the air is hotter after going over the engine.

Touching on the point of better flow through the cowl is trying to keep the air laminar as it leaves the cowl. I have a couple ideas for that in my head too. One of them it so actually make a diffuser box on the back of my rad that has two diverging sides to slow the air down and create a negative pressure and then inject my exhaust air into that diffuser to create a bigger negative pressure to help pull air through the rad. This is how F1 cars used to make down force(I think they still do to an extent but there are more rules about how they can do it). This idea is also touched on in Speed with Economy by Kent Paser. In the book he also adds some aluminum to have a converging diverging nozzle at the lip of the exit of the cowl. He also has it set up so the air doesn't have to go around sharp corners which should help air stay laminar and up to speed. In order to do that exhaust thing though, I would have to remove my muffler after the turbo so I could ad a 90 deg elbow right away. I'm not sure of the implications on turbo performance of doing that yet. More reading to do. I'm not too worried about noise as turboed engine's are usually quieter and the engine is small displacement and high rpm which helps too. But things to think of. Might as well put my exhaust to work!

I do have a cold air intake so all the air feeding my engine comes from a separate NACA into a box. Mic has the same intake. He also added the lip and saw temps drop I believe. He wants to switch his oil cooler position but is going to wait til after Oshkosh from what I gather.

I've been reading similar opinions on NACA ducts too. They are great for the least amount of drag but they really can't provide a huge amount of ram air. I think the big scoop on the bottom of our planes is fine because it's more or less directly in the airflow as the cowl slopes down. But it is making me revaluate my intercooler set up as that has two NACAs feeding it. I might be better with a smaller ram air intake. Gotta love experimentals!