The IndyCar Series is the premier series of the Indy Racing League. The championship, founded by Indianapolis Motor Speedway owner Tony George, began in 1996 as a competitor to CART. Citing CART's increasing reliance on expensive machinery and overseas drivers, George aimed to create a lower-cost alternative.

Due to the legal settlement with CART, the IRL was unable to utilize the name until the beginning of the 2003 season. From 1996-1997, the premier series was simply referred to as the Indy Racing League, with no genre designation. From 1998-1999, the series garnered its first title sponsor, and was advertised as the Pep Boys Indy Racing League. The contract was not renewed after the second year. In 2000, the series sold its naming rights to Internet search engine Northern Light for five seasons, and the series was named the Indy Racing Northern Light Series. After only two seasons, however, the sponsorship agreement ended when Northern Light reevaluated its business plan and ended all sponsorships. Incidentally, this name had been causing some mild confusion, due to the open-wheel developmental series called "Indy Lights".

No title sponsor has embraced the premier series of the IRL since the 2002 season. The only change coming in 2003, as mentioned above, when it adopted the title IndyCar Series. In 2006, IndyCar forged an alliance with Simmons-Abramson Marketing (headed by Gene Simmons of the heavy metal band Kiss), promising to be "actively engaged in the league's marketing, event, public relations, sponsorship, merchandising and branding efforts -- from its IndyCar Series to the venerable Indianapolis 500". Simmons also co-authored the new IndyCar theme song, "I Am Indy".

Cars

Vitor Meira's 2006 Dallara preparing for practice.

IRL is not an open formula, but neither is it a one-make or "spec" series. Instead, chassis and engine manufacturers apply to the League to supply cars for three year cycles. Currently, Dallara and Panoz provide the chassis, while Honda is the sole engine provider. A third chassis manufacturer, Falcon, once held the rights to produce a chassis for IRL events, but as no orders were ever made, no Falcon IRL rolling chassis were ever completed, and the company has since ceased to exist. Riley & Scott produced IRL chassis from late 1997 to 2000. In the series' first season, 1996, 1992 to 1995 CART chassis built by Lola and Reynard were used.

Superficially, IRL cars closely resemble those of other open-wheeled formula racing cars, with front and rear wings and prominent airboxes. Originally, the cars were unique, being designed specifically for oval racing; for example, the oil and cooling systems were asymmetrical to account for the pull of liquids to the right side of the cars. The present generation chassis however, are designed to accommodate the added requirements of road racing.

Indy Racing League officials have confirmed that the series will continue to use the current batch of Dallara and Panoz chassis for the balance of this season (2007). Both manufacturers have served as chassis manufacturers with the IndyCar Series since 1997 and their current three-year chassis suppliers' agreement was signed in 2003. However, all full time teams now use the Dallara chassis, the only Panoz presence being a few one-off Indy 500 entries.

The present Indy car has come into being since 1997 when Tony George specified new technical rules for less expensive cars and "production based" engines that outlawed the CART-spec cars that had been the mainstay of the Indianapolis 500 since the late 1970s.

Fuel

At its inception, the IRL used traditional Methanol racing fuel, which had been the defacto standard since the 1964 Indianapolis 500 Eddie Sachs - Dave MacDonald crash.

In 2005, driver Paul Dana brought the sponsorship of a consortium of ethanol producers to the IRL. For the 2006 season the fuel was a 90%/10% mixture of methanol and ethanol. In 2007, the League advertised "100% Ethanol" but in reality it was 98% ethanol -- the remaining 2% in the fuel is gasoline, which satisfies the US Government's demand that the alcohol be unfit for human consumption.

To compensate for the loss of power due to the use of ethanol, the displacement was increased back to 3.5L. Since ethanol gets better fuel mileage than methanol, the fuel tanks in the car were decreased.

Compared to methanol, human contact with the current IRL fuel is much less harsh, and the fumes much less irritating. The fumes are often compared with the sweet smell of apple cider or apple cobbler.

Engines

The initial 1996 IRL season, as well as the first two races of the 1996-97 season, featured 1994 and 1995 model year chassis, left over from the rival CART series competition. Those chassis/engine combinations were essentially the same rules utilized by teams which participated in the 1995 Indianapolis 500, which was sanctioned by USAC. The Menard engine used in 1996, however, was an updated powerplant from the 1995 version.

Starting in 1997, IRL cars were powered by 4.0 L V8, methanol burning, production-based, normally-aspirated engines, produced by Oldsmobile (under the Aurora label) and Nissan (badged as Infiniti). Per IRL rules, the motors sold for no more than $80,000, and were rev-limited to 10,500 rpm. They produced around 700 hp.

The engine formula was changed with the 2000-2004 formula. The displacement was dropped from 4.0L to 3.5L, and the requirement for the block to be production-based was dropped. This formula was used through 2003. In 2004, in the wake of several crashes including the fatal crash of Tony Renna and the severe crash of Kenny Bräck, the displacement was further reduced to 3.0L to curb top speeds.

Historically, Honda, Toyota and Chevrolet competed for the engine supply business, as Infinity was never competitive and switched to sponsoring the feeder Infinity Pro Series (now the Indy Pro Series).

As part of General Motors' discontinuance of the Oldsmobile name, the Olds motor was rebadged as the Chevrolet starting with the 2002 season. However, the effort could not compete with the Toyota and Honda programs starting in 2003. In August, 2003, Chevrolet announced its "Gen IV" motor, a rebadged Cosworth motor. At the time, Cosworth was owned by Ford. On November 4 2004, Chevrolet stated that it would be ending its IRL engine program effective with the end of the 2005 season, citing costs that exceeded value, according to then-GM Racing Director Doug Duchardt. "The investment did not meet our objectives," he was quoted as saying.

In 2003, Toyota came to the IRL from the rival CART/OWRS/CCWS series. Toyota won their first race in Miami, as well as the Indianapolis 500 the series title. However, Toyota had just one podium in the last seven races of 2004, and only Penske Racing fielded competitive Toyota-powered cars in 2005. In November 2005, Toyota company officials announced the company's withdrawal from American open-wheel racing and the immediate discontinuation of its IRL program, coinciding with its entrance into NASCAR's Craftsman Truck Series in 2004, and its discontinuation of its IMSA program.

Honda also came to the IRL in 2003, and by 2005 was clearly the dominant engine manufacturer. Starting in 2006, they became the only engine manufacturer in the IRL, and will continue in that capacity until 2009. The Honda engine is designed and produced by Ilmor Engineering Ltd, which is partially owned by Roger Penske.

Since the IRL has only one engine manufacturer, that manufacturer concentrates on minimizing engine failure and minimizing costs instead of defeating rivals. The engines have proven themselves to be quite durable -- there have been no catastrophic engine failures at Indy for the past 2 years, that also lowers the number of crashes. Most of the engines are used for multiple races, including those used for the Indy 500. The Honda motors are only available via lease arrangement from Honda, which costs approximately $US 2.9 million per season per car. Honda techs travel with the series, as well as attending all IRL team testing sessions. Virtually all teams like the current arrangement.

IRL engines are rev-limited to 10,300 rpm and produce approximately 650 hp. The valve train is a dual overhead camshaft configuration with four valves per cylinder. The crankshaft is made of alloy steel, with five main resembleing caps. The pistons are forged aluminum alloy, while the connecting rods are machined alloy steel. The electronic engine management system is supplied by Continental AG, firing a CDI ignition system. The engine lubrication is a dry sump type, cooled by a single water pump.

Specifications

Engine Displacement: 3.5 L (213 in³) DOHC V8

Gearbox: 6 Speed paddle shift gearbox

Weight: 1,525 lb (693 kg) on ovals; 1,600 lb (727 kg) on road courses

Power Output: 650 hp (481 kW)

Fuel: 98% ethanol 2% Gasoline

Fuel Capacity: 22 U.S. gallons (83 liters)

Fuel Delivery: Fuel injection

Aspiration: Naturally aspirated

Length: 192 in (4.88 m) minimum

Width: 78.5 in (1.99 m) (outside wheel rims); 74 in (1.88 m) minimum (measured at the hub centerline)

Wheelbase: 120 in (3.05 m)

Steering: Manual, rack and pinion

IndyCar Series teams & drivers

Main article: List of IndyCar teams

In 2007 18 cars fielded by 8 different teams (Penske Racing, Panther Racing, Andretti Green Racing, Rahal Letterman Racing, Dreyer & Reinbold Racing, Chip Ganassi Racing, Vision Racing, and A. J. Foyt Enterprises) competed in every race. An extra four teams (Roth Racing, CURB/Agajanian/Beck Motorsports, SAMAX Motorsport, and Racing Professionals) participated in partial seasons that included races other than the Indy 500. In addition, Panther Racing fielded an extra car in the final race of the season. Five more teams only competed in the Indianapolis 500 (Sam Schmidt Motorsports, Playa Del Racing, Chastain Motorsports, Hemelgarn Racing, and Luczo-Dragon Racing) and several other full and part time teams fielded extra cars in the '500'. Two more teams (PDM Racing and Team Leader Motorsports) entered cars in the Indy 500 but failed to qualify. Andretti Green has the most championships (3) and most wins (31) in series history. Foyt Enterprises is the only team that has participated in every IRL IndyCar series season and in fact has fielded a car in every series race. Five of the eight full-time IndyCar teams have previously competed in CART (although Foyt has not since the inception of the IRL).

Sam Hornish, Jr. currently leads all IRL IndyCar Series drivers with 19 victories and 3 championships. However, Hornish is leaving the series for 2008 and leading active driver will be Dan Wheldon and Tony Kanaan who each enter the season with 13 wins and a single championship. Scott Sharp is the all-time series leader in race starts with his tally standing at 146 at the end of the 2007 season, when he decided to leave the series to pursue sports car racing. The active leader is Hélio Castroneves who has 97 starts entering 2008. In 2007, IndyCar was the only major racing series with three female drivers including Danica Patrick, the series' most popular driver 3 years running, Sarah Fisher and Milka Duno.

Indy Racing League IndyCar Series seasons

1996: Scott Sharp and Buzz Calkins tied in the final standings, and were declared co-champions. Calkins had one win (Sharp had no wins) in the short season, three-race season, but the Foyt team scored more team points.

2006: Sam Hornish, Jr. and Dan Wheldon tied in the final standings for first place. Hornish clinched the championship based on tiebreaker of most victories during the season.