I went to Laguna Seca Raceway last week and used Racechrono to log data.
When I tried to do some video overlay using Dashware, I found that the GPS data and the OBD2 data(RPM, Throttle Position, and intake air and coolant temperature data) was off on average of 3 seconds.
The RPM and TPS trace is ahead of the GPS speed by about 2.3~3.8seconds.
The hardware that I'm using to log it are:
Samsung Galaxy Note 2
Qstarz Q818XT at 5hz dgps mode
ELM327 OBD2 Bluetooth
I did noticed on track that I had to wait a few seconds for the Racechrono to report the lap times after crossing the start/finish line, so I'm wondering if the GPS was being logged a few seconds late.
It feels like Racechrono is logging data at variable intervals and it's doesn't seem to be working so well.
I love the +/- Sector times and keeping lap times, but now I'm questioning the data's validity.
Torque Pro that I've used on some other sessions, although it could be lower in accuracy/data rate, I get consistent data and everything lines up.
I can provide the .csv files and whatnots upon request.