Sorry, Kevin, got busy there and I didn't get back to it 'till tonight.
As I look through my data (27 runs with the variables recorded) I am afraid I didn't take enough data to help your cause. I see I usually recorded the OAT on the ground, which doesn't mean much since about half the time we have an inversion going. I would just put OAT and altimeter setting into the E6B function in the GPS and then fly at my 9,000 ft density altitude (except during mid-summer, when that would put me too close to the ground, then I would do 11.000 d.a. Meanwhile, I am madly making modifications, and it is hard to find much of a temperature swing without a modification (i.e. 6 months without a mod...perish the thought). 4 different props doesn't help of course.
I was more interested in making two runs at the same temp with a small mod to compare and test my theories.
I follow what you are saying re: a higher pressure at the same density altitude in the summer...I couldn't find anything to really disprove that. I'm not sure where I got the idea that I was going faster in the winter, because reviewing the data doesn't support that idea.
I will do what I can to get you some data to work with...maybe in the spring here I can get the temperature swings needed...but, with the race season starting, I must make my mods.
I did see I have gained about 15 kts. since I first flew the airplane in the fall of 2002, so I don't feel like a total idiot.
BTW, my record recently is 1 minute, 55 seconds time-to-climb brake release to 10K ft.
Ok, Ok, I start at 7650.
John