Beat time to Race Garage was a mission in Jak II. Krew was looking for a racer for a client of his and his eye had fallen on Jak, who had to drive to her Race Garage within three minutes for her to consider getting Jak on her team.
Yet another race through Haven City, nearly the same as last time except the Main Town and Mar Memorial Stadium sections are added to the track. There's no imminent threat of Krimzon Guard blockades this time nor do you need to keep your current zoomer (it's recommended to only use the small single-seaters). If your current one is broken and therefore slower than normal; switch to a new one.
Following the mini-map you'll be able to beat the time limit of three minutes, just make sure you cut corners and drive at full speed as much as possible. It is recommended to drive on the lower level to avoid hitting zoomers, although you need to stay clear of any guards lest you activate the alarm system. At the Stadium walk up to the race garage to start a cutscene immediately leading to the "Win JET-Board stadium challenge" mission.