The IZOD IndyCar Series returns to Iowa Speedway for this weekend's Iowa Corn 250, a night race and the third oval contest in a row, after Texas and Milwaukee. The defending race winner is Marco Andretti, who earned his first victory since 2006 with a stirring and competitive drive last June.

This year's race will be very unusual in that the customary single car qualifying is being put aside in order for the drivers to earn their grid positions in three 30-lap heat races. The order for those heat races will be determined in Friday's second 45-minute practice session, being held at 3:30PM EDT.

Race No. 1 consists of the even-numbered entries, starting with the 10th-quickest in practice and will determine the even-numbered positions in the starting field from 10th on down. Race No. 2 is for odd-numbered positions, starting with ninth-quickest driver in practice and determines the odd-numbered starting positions from ninth on down. The third race is for the eight quickest drivers and will determine the polesitter and the balance of the first four rows.

Another wrinkle in this novel qualifying system is that in each 12-14-minute heat race, cars will carry about one-third of a tank of E85 fuel (tanks hold 18.5 gallons), which shouldn't impact tire wear or the car's consistency, according to INDYCAR officials. The cars will use a maximum 37-degree rear wing flap angle on this compound banking.

Rahal Letterman Racing managing director of motorsports Tom Anderson - Anne Proffit photo

Rahal Letterman Racing managing director of motorsports Tom Anderson - Anne Proffit photo

"It is going to be challenging because the drivers will all nod and say, 'Yes, this is just a qualifying race and it's only to determine a specific position to start and, really, the big show is Saturday night,' '' Rahal Letterman Racing managing director of motorsports Tom Anderson said. "That somehow seems to change when they put their helmets on, so it will be quite interesting to see and I'm sure it will be worth the ticket price for those that show up" on Friday night.

There are already two 10-lap penalties to be served at the start of the race, as both EJ Viso and Tony Kanaan from KV Racing Technology have elected to change their Chevrolet engines prior to the start of Friday morning practice.

Just before this race, engine manufacturers are able to submit any proposed changes to INDYCAR if they believe their engines are statistically more than 2.5-percent deficient to the balance of the field. The first to ask for assistance is Lotus through Engine Developments Ltd, as it's fairly obvious they've been behind Chevy and Honda since the season began.

INDYCAR's engine director Trevor Knowles may allow alterations to homologated items that make up two percent of shortcomings, with the alterations, if allowed, introduced only as new engines are sent to the team, in this case HVM. Lotus/EDL will have to present data to support their case and once approved, INDYCAR intends to inform other manufacturers which components are being changed, with those parts sealed before being incorporated and the old parts remaining homologated until the 2013 homologation date.

A second such revision may be permitted at the close of the season, with work to be completed and parts homologated and sealed prior to the first race of 2013.

Because of the heat races this weekend, NBC Sports has delegated extra air time for the IZOD IndyCar Series on Saturday beginning at 7:30PM EDT with IndyCar 36 (Charlie Kimball), then showing the heat races prior to the start of the Iowa Corn 250 and showing the Sukup Firestone Indy Lights race from Iowa directly afterwards.