I'm currently looking into the 1990 F1 season. I've been looking at a few wiki pages and getting some inside info from F1 rejects as regards some of the more pathetic entries of that season (Life, Coloni etc.)

I watched the first round, Phoenix, recently and am just getting to grips with the old format of the race weekend. Starting from pre-quali I gather this:

1. Any teams which were not in the top 13 in the 1989 constructor's championship must take part in pre-quali. As an example, nine drivers took part in the pre-quali for the US GP. T

2. The fastest 4 of these drivers go on to real qualifying (meaning 30 drivers at most, will have the chance to get into qualifying.)

3. The slowest 4 from real qualifying don't get to race. That means the largest grid is of 26 cars. Of course, if a driver in the top 26, should be disqualified or unable to race, the fastest of the non qualifiers gets to race.

Yes, simple. But there were two qualifying sessions. Thats where I am confused. Quali 2 didn't appear to have an effect on how the drivers lined up on the grid and their times, at least in Phoenix, were some 20 seconds slower than the times in Q1. What was the purpose of this second session and why were the times so considerably slower?

When I'm following the season I want to understand completely whats going on. I don't like wondering through the year, "why this and why that?"