My GPS has an update lag of about 1 second, so for testing 0-60 it is not very accurate.
I plot out the motor rpm on my inverter and based on the graph it produces, I measure 0-60. The GPS helps by telling me when I've hit 60 though. I've also programmed my inverter to start a timer once I hit the throttle and stop once I hit 60 mph. When I reach zero speed it resets. Basically it measures 0-60 every time I start from a stop.
As a speedometer, the GPS works great.
The GPS is made by Garmin, it's discontinued, but the UI is the same on all the Garmins I've owned.
Noticed you were using GPS....
I was planning on dumping my mechanic speedometer and going only GPS as well.
Does your GPS do 0-60 splits?
Do you like it and what model number is it, if you don't mind me asking?
Congratulations on your top speed.