Officers were called to reports of a fight in St Norbert Road, Brockley, south-east London, on Saturday afternoon.
The 17-year-old was in the car which had hit a lamp-post, but he died later in hospital.
Police believe group of people threw missiles at the vehicle as it sped off.
A post-mortem examination found the cause of death to be multiple injuries, consistent with being in a road traffic collision.
The four arrested men, aged 19, 20, 21 and 23, have been released on police bail.
Two other men who were in the crashed car suffered minor cuts to their hands.
Four men have been arrested in connection with the death of a teenager who was in a car which crashed after it was attacked.