In chat, site moderator PearsonArtPhoto raised an interesting question after I'd pointed out that watching this launch could be disguised as watching "A car go faster than any car has gone before."
How long will it take the Tesla Roadster to beat the all time record for the fastest car? PearsonArtPhoto's question in chat
Popular Mechanics has written an article on it, but they only discuss how fast it will go at its top speed, and the speed at which it leaves the "Earth-Moon system". According to Harvard-Smithsonian astrophysicist and spaceflight expert Jonathan McDowell, who was in email correspondence with PM, the car will go several orders of magnitude faster.
"At separation, the Roadster will be going between 11.5 and 11.8 km/s relative to Earth," ... "This is 25,700 to 26,400 mph, so say about 26,000 mph give or take. It will slow down as it goes 'uphill' and departs the Earth-Moon system at about 7,400 to 9,500 mph—relative to the Earth."
Elon Musk's Roadster Will Break the Record for Fastest a Car Has Ever Traveled - Popular Mechanics
The current fastest road legal car is cited at being 277.9mph (447.2 kph), a record held by the Koenigsegg Agera RS and the car with the land speed record is the Thrust SSC, clocking in at 763.0 mph (1228 kph)
So how long will it take the Roadster to beat either of these cars?