I brought the Yi from my daily driver in Korea, but I also bought two of these super cheap cameras to try them out. $22 on Amazon Prime and I love them. They have a "driving mode" that turns them on and off automatically and will continuously record over top of other video. The video is superb. As the reviews do say, the sound kinda sucks, but who cares in a racecar. These exceeded my expectations and I will buy more for other things.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I have a Yi camera as well. I dont like how it segments the video, and classifies higher g-force braking, turn, and acceleration events into the "Emergency" folder. I can't disable this. If I want to publish or share anything, I have to go find it all and stitch it all together and its just a pain in the ass. I did change the settings to the least sensitive, but it still does it. Maybe Im just not smooth enough at the wheel yet. But check out the link above. Good cheap cameras that are near go-pro video quality.