Hi harald
On a recent trackday, I was using HLT with Tom Tom mount. I loaded up the track, & used autostart which seemed to work perfectly. During the laps the gForce and speed were on shown the display
When I stopped after 5-6 I overlayed the data on the video but HLT had only recorded one lap of ...

Hi Harald
A question on your comment on Timing Accuracy

iPhone3G's and 3GS's internal GPS: better than 0.5 seconds
iPhone4's and 4S's internal GPS: better than 0.1 seconds
Any iPhone directly integrated with a supported external sensors (Emprum's Ultimate GPS, Dual's XGPS150, TomTom car kit, and G ...