Dear Sandra M,
From Gran Hotel Torre Catalunya to Circuit de Montmelo is 1 hour aprox.
You shpuld get the train in Sants Estació to Montmelo (30min) and then get a bus from Montmelo to the Circuit (30 min)
Sorry, I 'm not familiar with formula 1
The circuit's website says there is a special bus service from the city centre on Grand Prix weekends. However that goes from Barcelona North bus station which is a fair walk from the hotel. You could be better getting the R2 line from Barcelona Sants then walking (45 minutes) or catching a local bus.
the racetrack: Circuit de Barcelona-Catalunya, is outside of Barcelona, so you will need to take train first + local bus (it will take about 2 hours). this hotel is literally a 1 min walk from a major train station, so if you want to take train ride, then this is a good choice. but if you want to live physically closer to the racetrack, then you will be outside of Barcelona.
Not close, But it is on the main Train Station, so there should e a public Transport from there
Get an answer from Gran Hotel Torre Catalunya staff and past guests.