It's been impossible to do much testing in the past two months due to weather. I can't get out there in a skinsuit if the temp is below 55 degrees - it's just too uncomfortable. And any breeze at all invalidates the data; so that eliminates lots of days.
But yesterday I was able to get another set of data collected on my P2K. So now I have three data sets with the same setup. My CdA results from three different days on the same test course are 0.228, 0.230, and 0.235. Based on n=3, my average CdA is 0.231 and the standard deviation is 0.0036. These numbers reflect skinsuit, TT helmet, shoe covers, no gloves, Zipp 303 front wheel, and power tap with Kinlin XR-300 (30mm) rear wheel.
My Cervelo P2K frame was slightly damaged in a crash last year, so I'm about to move my P2K components over to a Cervelo P3 frame a teammate recently gave me. I'll set it up exactly the same as my P2K, except I'll run a Zipp 404 on the front instead of a Zipp 303. The only difference between the new test setup and race setup will be the absence of my disc wheel during testing.
These aren't my bikes, but depict my old P2K frame and new P3 frame:
I'll be interested to see how much difference the frame change and 303 vs 404 change make to my CdA.