As IZOD IndyCar Series teams prepare for this weekend's season-opening race, the most-talked about element of the 2.6-mile street course in Sao Paulo, Brazil, is the length of the back straightaway, which is just short of a mile – making it the longest straightaway in series history.
“The Sao Paulo track is definitely a street circuit. In it you can see elements of the Long Beach track, a bit of Australia, and even some of the Denver track,” said Newman/Haas/Lanigan Racing Senior Engineer Craig Hampson (above). “But the only other places we had such long straightaways were [CART/Champ Car events in] Mexico City and Elkhart Lake. We don't know how bumpy the pavement is going to be, so that's an open question going into the event and will determine how stiff we will want to run the springs and dampers.
“As with any new circuit, the most important thing is to run a series of simulations to determine what the cornering speeds and straightaway speeds will be,” Hampson added. “This then allows us to select the gear pattern and correct gear ratios. We begin by creating a CAD model of the inside and outside walls of the track layout. This is then used to create an assumed driver line, which is transformed into a mathematical model of the route the car will take. Our simulated car is driven around this route and the computer iterates to the maximum speed it can attain based on our best assumptions of tire grip level, aerodynamic downforce and drag, and engine power. We're usually pretty close on predicted lap time and speeds, although some adjusting of gear ratios is typically still required at the event.
“So much depends upon your choice for track grip. If you're off by even a small amount, it has a pretty big effect on the resulting speed. The same simulation also helps us to make decisions about the starting ride heights, the aero setup, and brake cooling.”
Not only will the Sao Paulo Indy 300 mark the first race for the new season and first event for Hideki Mutoh at NHLR, it is also the first time the series will only run two days at an inaugural event. In addition, it will be the only road/street event on the 2010 schedule that will not have three days of track time. Although this is an added challenge, Hampson notes it is the same for everyone – and reckons it could be an advantage for a team known for preparation.
“To be honest, having only a two-day event at a brand-new circuit, with a new driver for the team, is far from ideal,” Hampson said. “You can usually make your best improvements overnight after a good study of the data. The driver also does better when he can ‘sleep on it' after a day of learning the track and how the car is behaving. This time we don't have that overnight opportunity, because practice and qualifying are the same day. So we need to ‘come off the airplane' with a setup that is close, otherwise we probably don't have enough time to improve the handling.
“Also, if we have any sort of wall banging that damages the car, it will be tough to get it fixed in time for qualifying. We need to be sure we keep running and logging laps. If you have a mechanical problem, or even something like a driver fit issue with the seat or belts, it will really take away from your weekend program. However, the schedule is the same for everyone. So, if we have managed to do a better job in our preparations, it could actually prove to be an advantage.”
Hampson added that the realignment of the series calendar, grouping similar tracks in strategic clusters throughout the season, has been a significant benefit for the teams in terms of time management. The first four races of the season will take place on road and street courses, while the following four are on ovals. Another five events will be held on road and street races and the season will conclude with a stretch of four events on ovals.
“The way they have arranged the schedule this year is much better,” said Hampson. “From oval to road track, the car is totally different. We use different suspension, brakes, wings, dampers and it's also a different mindset for the engineering staff. So, a changeover from one type of track to the other is a massive undertaking, and extremely difficult to do if we have only a couple days between events. The way they have arranged the 2010 schedule means we only need to do the road track to oval changeover – or vice versa – three times. This is going to make it much easier on the team and the mechanics."