Team Purex/Dreyer & Reinbold Racing's Robbie Buhl drives a G Force powered by an Infiniti Indy engine.
Oldsmobile continues to dominate with its IRL Aurora V8.
The Indy Racing League, its suppliers, and racing teams are still in the tinkering stage a year after some major rule changes. The current engine, chassis, and tire specs will remain at least through the 2002 season. In the meantime, teams find ways to squeeze more from their rides, suppliers look for improvements within spec constraints, and IRL assesses it all, always searching for the best in excitement without sacrificing driver or fan safety.
The need for speed
Oldsmobile and Infiniti will again battle it out on the track as the two IRL-approved engines. The IRL Aurora V8 is still the engine to beat, but Infiniti's Indy engine definitely made some noise in 2000. Its prime champion, Eddie Cheever Jr., of Cheever Indy Racing, garnered a victory last June at Pike's Peak followed by four other top-five finishes, finally finishing third in the championship the highest placing ever for Infiniti in the Indy Racing Northern Light Series. "The Infiniti went from being just a participant to a winning powerplant," raves Cheever.
Cheever's not the only one noticing. Midway through the season, Team Purex/Dreyer & Reinbold Racing's Robbie Buhl joined the effort, running five races with Infiniti power. This year Cheever, his new Indy 500 teammate Scott Goodyear, and Buhl will run an all-new powerplant, the Infiniti Indy 35A. The new engine is smaller, lighter, and has a lower COG than previous Infiniti Indy engines. It was first designed in Japan as a five-liter version for the 1999 "24 hours of Le Mans," and then refined in Europe to meet IRL regulations as a 3.5-liter, methanol-fueled engine.
At presstime, both Cheever and Goodyear logged more than 400 trouble-free miles on two different 35As. "On our first day of testing with the new Infiniti engine we were only one-tenth of a second off our fastest time at Phoenix after running just under 200 miles," says Cheever. "It's a totally different engine, it's like having a brand-new everything. We are starting over from scratch and have to perfect our recipe." Goodyear shares his excitement. "I am delighted with the performance of the Infiniti 35A for its first time on track," he says. "Compared to all the engine programs that I've had on track for the first time, I was very pleased that this one occurred without any major interruptions."
To guarantee reliability, the Infiniti technical team spends countless hours testing and fine-tuning the engine on a dynamometer so its ready to run right out of the box. The new engine has been in the works for about 18 months. It incorporates a 180° crankshaft, mandatory for 2001. "The 180° crank calls for a different engine design philosophy," explains Charlie Bamber of the Infiniti Indy design team. "It has a very different torsional behavior. There's a lot of modeling involved to establish the optimum configuration for the crankshaft counterweight to cut the bearing loads and boost the torsional stability of the crankshaft valve train."
Going from a 90° to a 180° plane calls for a new firing order. Though Bamber isn't ready to divulge that sequence, he says Infiniti engineers are running mechanical simulations to determine the order that gets the best torsional characteristic with the crankshaft. Infiniti designers are also using CAD for cycle simulation which measures the air pulse going into and out of the engine intake and exhaust system. This helps them get the best camshaft arrangement. Beyond this, ports are designed in CAD and then refined in CFD. Engine components see FEA to trim excess material and cut the weight.
"One of the nice things of having an engine at the minimum weight is that it lets us put ballasts on the car where they're most useful," says Cheever's Team Manager Richard Caron. "For example, with oval racing we want the weight very low and toward the left-hand side so we can put skids on the car and use different materials. We can change the weight distribution fore and aft, which lets us do a lot of things that alter handling."
With just three drivers out of 33 this season, the Infiniti team has its work cut out. But neither they nor the Cheever Indy Racing team seem worried. "We hope we have an unfair advantage or an edge," says Caron. "Scott is going to be a formidable ally to Eddie and we want to give him every opportunity we can to win this race." Says Cheever, "This new engine is the best Infiniti has to offer when it comes to motor racing. This is the future."
Time will tell. For now, however, Oldsmobile is the reigning IRL champ. The IRL Aurora V8 debuted as a 3.5-liter version last year, running at the League mandated 10,700 rpm and carrying the 180° crank. Because the engine already met the IRL's maximum bore size, minimum block height dimension, and minimum weight, Oldsmobile didn't need to produce an entirely new package. According to Joe Negri, GM Racing IRL/Road Racing Group manager, last year was the team's best ever in terms of durability. Even with the 180° crank, which makes the engine vibrate considerably more than with the 90°, Negri reports no problems.
One reason might be the Hy-vo chain Oldsmobile began using last year. With the new crank, timing chains started breaking but designers had it licked by Indy using this chain. The Hy-vo has been used in the past on transmissions, but in this case, was developed in conjunction with Roush Industries for the IRL Aurora V8. Since the switch, Oldsmobile has yet to break a timing chain.
This year, Oldsmobile continues to tinker with its winning formula. "We constantly update the cams," says Negri, "and we have a new spec of cams and induction system that will be ready in time for Indy. At the end of last year we pulled ahead a new cylinder-head intake port design optimized for the 3.5-liter engine and we are continuing to develop and improve that." The rest of the engine is regularly tweaked. "We are running at least one 500-mile dyno test each month, sometimes more, and every time we do we learn something new," he says.
Engineers also spend considerable time improving engine reliability. The 3.5-liter engines are generally more reliable than the four liters because they have a shorter crankshaft stroke which slows the piston speed down by more than 150 ft/min. But to analyze various engine components, Oldsmobile engineers use several different software modules. "All the parts are designed typically in a 3D solid system," explains Head Engine Designer Roger Allen, "but we use generative part-stress analysis to quickly look at it from a stress standpoint. The majority of the work is accomplished in 3D and then we cut the patterns straight from those models and rapid prototype the components." Unlike the Infiniti Indy team, Oldsmobile designers don't use a lot of FEA or CFD analysis. "We are always looking for ways to improve performance but it is generally based on competitive analysis," explains Allen. "Funds available for updates are always a function of where you're at relative to the competition the more pressure there is, the more money we'll get to do better things."
Expect more competition in 2003 as at press time, Toyota announced its plans to join GM and Infiniti in supplying engines through 2005.
Relatively unchanged from the 2000 to 2002 package, new engines will continue to be 3.5-liter, 32-valve dual-overhead cam, normally aspirated V8s. However, there are two notable changes in 2003. Specs will allow a second fuel injection nozzle/cylinder, providing a broader midrange powerband, and camshafts can be chain or gear driven.
Last year the IRL mandated chassis revisions with an eye toward safety. Wider cockpit openings, thicker headrests, added anti-intrusion barriers, and longer sidepods were a few key enhancements. This year it's implemented a collapsible steering shaft and rear-wing retaining system as part of the 2001 update kit. The new steering shaft collapses 1.5 to 2 in. during frontal impact, absorbing shock. The rear-wing retaining system uses Zylon cables to keep the rear wing from flying off during high-speed collisions. The system is a close cousin to the Zylon restraint cables known as the Suspension & Wheel Energy Management System (SWEMS) mandated in 1999.
Chassis makers Dallara Automobili S.R.L. (Italy) and G Force Technologies Ltd. (Great Britain) also incorporate specific safety and aerodynamic improvements as part of their update kits. For instance, G Force added more crushable material by lengthening its sidepods, and also refined the underwing. Dallara added all new bolt-on bodywork which includes a new undertray, sidepods, radiator boxes, air box, and engine cover.
In open-wheel racing, a race-car's performance depends largely on aerodynamics. Dallara spends the bulk of its time in the wind tunnel. "The trick is always to cut drag and increase downforce," says Dallara's Sam Garrett, U.S. technical representative. "We are always looking for a more efficient design. Between last year and this year we've kept the same level of downforce but cut drag about 40 to 50 lb."
In designing the car, Dallara engineers rely on a combination of computer analysis and experience. Explains Garrett, "We do a lot of FEA but we also have to do crash testing. For example, impact tests on the nose of the car show how much energy it absorbs. If the nose is hit at a certain speed with a given weight, it has to decelerate at a specific rate or within a range of rates so that it absorbs energy without transferring it directly to the driver."
One complaint about Nascar is that the cars are too unyielding, absorbing too little energy on impact. Here, IRL cars excel. Since its beginnings in 1997, the League has made safety priority one, adding features like a rear attenuator that absorbs about 50 g when a car goes backward into a wall. Better headrests and more room in the seat make drivers more comfortable. Foam surrounds them so they almost become part of the car. Also, longer sidepods, more honeycomb material in the radiator ducts, and collapsible shafts in the gearbox all help absorb more energy in a crash. According to Garrett, with the rules that went into effect with the 2000 car, Dallara's gone beyond the specifications for nose impact and roll-hoop crush tests.
One chief chassis component, the sequential gearbox from England's Xtrac Ltd., has improved with a new lightweight transmission. "The lightweight, internal cluster assembly should prove popular with front running teams looking for a gearbox-related performance advantage," says Jon Marsh, senior design engineer. The new parts are only intended for qualifying trim when the teams can tolerate less gears and benefit from running lightweight internals for short high-speed runs. The lightweight four-speed cluster cassette has narrower gear ratios and lighter shafts that can be swapped easily with the standard six-speed unit before or after qualifying.
"During the race it's very important for the driver to have an even spread of ratios to maximize engine performance and accelerate after a pit stop or yellow flag caution," Marsh explains. "Teams may run two 'top gears,' however, to perfect terminal speed and to account for traffic and differing track conditions. For qualifying the team can afford to remove two or three redundant gears as the driver has time to build up speed before attempting a timed high-speed lap. They may only run one top gear or perhaps two to allow for wind or temperature variations."
As the sole tire supplier for the second year running, the thrill is far from over for Bridgestone/Firestone's general manager of racing, Dick Davis, but even he admits some competition would be nice. "When you're in competition, you want to be right on that edge. We used to have virtually a different tire for every track. Now we've standardized them and we don't have nearly as many specs as we used to. There's no reason to." Still, being the only tire in the series leaves no room for error, and Firestone relies on its extensive experience.
"We use very little modeling," says Davis. "The teams can put strain gages on the push rods so we can calculate vertical and lateral loads. We actually worked with the chief engineer of one of our CART teams and developed what we call the GEM device, a grip evaluation meter. It's an instrumented hub that sits at each corner of the car and measures lateral force. This lets us evaluate front and rear balance and inside versus outside balance. We aren't using it now because we are doing very little testing, but more maintenance. One sensor that has been a tremendous help to the tire companies and the race teams is a pressure sensor. A sensor sits on each wheel to monitor tire pressure and sends a signal back to the pit if it senses the tire losing pressure." Each pressure sensor costs about $1,000 per wheel and teams have many sets of wheels. According to Davis, most of the CART teams and about half of the IRL teams use them.
During practice and testing, teams also use a laser that measures ride height the distance from the track surface to the bottom of the racecar. The car's under-side is designed to create down-force at high speed so ride height is critical to how much downforce it generates, says Davis.
After all the prep work, tires are put to the real test on the track. A typical race is about 200 miles and teams generally use seven sets of tires per weekend whether for oval, road, or street racing. Indy, however, is far from typical.
"When it comes to Indy the rules are different," says Davis. "There's absolutely no limit to the number of tires that teams can use for the entire three-week period. That makes it difficult to guess, particularly if you don't have experience, how many tires you should take." Says Davis, for a typical race weekend with about 33 teams taking 28 individual tires per team, Firestone comes prepared with about 1,000 tires. Contrast that with Indy. "We're estimating that there's going to be only 33 cars in the race but there are many more than that trying to qualify to fill out the 33-car field. We'll take more than 6,000 tires and that includes two different staggers," says Davis.
A stagger is the difference in diameter between the right rear and the left rear tire. On oval tracks making the right rear tire bigger in diameter than the left rear helps the cars turn. "Typically in Indy a small stagger is when the left rear tire is about 0.40 in. smaller than the right rear. The biggest stagger is about 0.51 in. but the bigger the stagger, the more difficult the car is to drive,” Davis points out. “With stagger options, we are never sure who’s going to use what so we take plenty of both. We may not use all 6,000 tires but we can’t risk running short.” Davis says even when facing competition the rules dictate that Firestone be ready to supply half the field regardless of how many cars they actually outfit.
Midrace tire changes can make teams sweat a little. Says Davis, "Race tires must be consistent throughout the life of a given set, which means the grip doesn't go away as it wears. They also must be consistent from set to set so that the cars' dynamics don't change. Since we came back to open-wheel racing six years ago we've earned a reputation of having extremely consistent tires throughout the life of the given set and from set to set, so that when the second set is put on it handles the same as the first."
The work doesn't end with the race. Firestone takes several sets of tires from the fastest cars that have run a full-fuel stint, typically about 70 miles, back to its lab in Akron, Ohio. There, engineers cut them apart and analyze them to see that every-thing's still intact. A state-of-the-art security system sees that each and every tire carries a different bar code. "We have a complete history on each tire from cradle to grave. It helps us make sure we get all the tires back because we certainly don't want them falling into a competitor's hands," says Davis.
Each tire is subject to X-ray or holograph analysis. A Firestone-designed lettering machine puts the Firehawk name on both sides of the tire using a heat-letter-transfer method. According to Davis, it's a challenging process because technicians must constantly be mindful of time, temperature, and pressure conditions so that the machine doesn't damage the tire cords.
One unique, albeit surprising, fact about the race tires is that they can freeze and crack. "If the tires are going through some inclement weather where the temperatures are at or below freezing during shipment to the warehouse or track, we have to haul them in heated trailers," says Davis. Firestone also has a minimum track temperature below which it strongly suggests teams don't run 50°F because the tires won't heat up and generate grip. In a marginal situation, Firestone suggests cars do an extra warm-up lap to heat the tires.
In the cockpit
Winning a race takes more than even high-tech engineering resources can provide. Also mandatory is a cunning driver not afraid to push to the edge. Indy Racing driver Greg Ray of Team Menard points out, "We have to understand the design and mechanics of the car so we can see and feel the advantage. It's somewhere between mathematics, science, art, and black magic."
The more aerodynamic the cars become the more drivers search for balance. "We take corners at speeds of 210 or 220 mph," says Ray. "From the grandstand the car looks like its planted on the ground but its actually sliding, we're breaking all the laws of physics. The car is more like an F-16 on the ground because of the aerodynamic package. The best Ferrari on the showroom floor pulls about 0.9 g in the corner. Our racecars can pull upward of 6 g instantaneously." When drivers talk about balance, Ray says they're describing the balance between the front of the car and back so that even when the car is sliding, they still have control.
Countless variables challenge drivers and engineers from track to track: Different straightaway lengths, degrees of banking, corner entrances and exits, and so forth. "The difference from one track to another is huge," Ray explains. "Textures and pavements, where the motor builds horsepower, and grip levels are all different. Because we run all over the country dealing with variant air densities, pressures, and humidity factors tire wear and grip changes with the track."
Data-acquisition systems help drivers deal with the incongruity. For instance, live telemetry lets Cheever Indy Racing monitor more than 50 different channels during the race, explains Caron. "We measure things like tire pressures, which tell us what is happening to the balance of the cars. We also monitor output from the engine management system to calculate fuel strategy." That information tells teams how much fuel is used on each lap, taking into account green and yellow flag laps, and adjusting fuel consumption strategies accordingly, all via computers. Programmable dashboards let drivers see many different parameters, be they lap times, temperatures, laps to go, or pressures.
To handle all the data, teams are looking for powerful, yet portable design hardware and software. This according to Richard Werneth, vice president of Computer Aided Technology Inc., a software house in Buffalo Grove, Ill., that's joined forces with Dreyer & Rein-bold Racing. "Some team engineers download data from the cars and look for lap-top friendly products that run in a native Windows environment. Engineers from Team Purex/Dreyer & Reinbold Racing are switching from 2D to mainstream 3D systems such as Solidworks for mechanical solid-modeling design engineering."
3D modeling lets engineers visualize the design, check for interferences within the chassis and body design, and verify findings quickly. Often, says Werneth, engineering takes place at the track. "With a 2D product," he explains, "engineers had to send data out and have it recreated in 3D mode for manufacturing. Now they can create and cut parts at the track without all the administrative functions."
Much time is spent analyzing the performance of the car, the data that's collected, and new ways to interpret that data, says Hayden Burvill, race engineer for Dick Simon Racing (DSR) and coowner of Windrush Evolutions, a San Francisco design business. "We try to turn it into curves or scatter graphs or something similar so we can look at it simply. We don't just simplify the data for ourselves, but also for the driver because we can't overload him with technical information."
Though the cars must meet certain specs, there's plenty of room for engineers to implement their ideas. For example, according to Burvill, the team engineered a safer seat for DSR driver Stephan Gregoire. The composite shell is relatively thin made from carbon fiber and Kevlar, and is in the shape of Gregoire's body. That shell is laid into the mandatory foam bead and resin mixture currently used for seats. "We made something that provides the maximum contact with his body, almost a ballistic layer in the seat," explains Burvill. "This becomes an energy-absorbing nest that fills a large void in the cockpit."
A different animal
In racing its not only about technical information, engineering, and mathematics, its also about a common goal without ego and without blame, says Ray. "Team engineers must have good chemistry and dialog. We prepare extensively for one moment and it's either immediate gratification or immediate disappointment. Either way, we win together and we lose together."
2000 ushers in big changes
Key chassis improvements included a wider cockpit opening at 19 in., providing better head protection for the driver through thicker head-rests. Additional anti-intrusion barriers on the chassis sides improve side-impact performance. Constructors incorporated better SWEMS mounts into their new chassis. Also, sidepods were raised from 16 to 17 in. and lengthened to prevent inter-locking wheels. The new chassis saw higher impact and load testing. Lighter transmissions with a sequential shift pattern and an improved rear-attenuator attachment were also new.
Cars would ride only on tires supplied by Bridgestone Firestone Inc., as Goodyear Tire & Rubber withdrew from IRL and CART competition. The Firestone Firehawk became the IRL staple.
Though chassis changes were plenty, the major revision in 2000 was a new powerplant. The new formula called for an engine reduction from four liters to 3.5, and new crankshafts that changed the engine firing order and brought a new sound to Indy. With the 2000 season, IRL no longer required the engine to be production based, but it had to be submitted by an auto manufacturer.
Teams could own, maintain, and repair their own engines. The league still controls engine revolutions through rev limiters. All 3.5-liter IRL engines have a rev limit of 10,700 rpm.
New engines have a shorter crankshaft stroke, decreasing piston speed by more than 150 ft/min from the prior level. Teams were able to re-engineer four-liter engines by shortening the stroke with a new crankshaft, camshaft, pistons, and connecting rods, essentially converting it to a 3.5-liter engine for about $15,000.
Team Penske returns to Indy
CART drivers in the IRL aren't new, after all CART champion Juan Montoya drank the milk in the Winner's Circle after last year's Indy 500 victory. What is new, however, is seeing Team Penske in the mix. Penske, winner of a record 10 Indianapolis 500s, hasn't entered a car since 1995. This year Team Penske drivers Helio Castroneves and 2000 CART champion Gil de Ferran will run at Indy with Dallara chassis powered by Oldsmobile engines developed by Ilmor Engineering.
"It's a huge undertaking, but we're ready for the challenge," says Tim Cindric, team president. "I know Roger's brand and the Penske name is based a lot on what he had done at Indianapolis and I know he's forever grateful for that."
Open-wheel racing fans hoping to see the two rival racing circuits reunite shouldn't hold their breath, however. Earlier this year at the State of the Series press conference, IRL's Bob Reif, senior vice president of sales marketing and chief marketing officer, made the League's plans clear. "This is going to be a building-growth year for us," he said. "We think the on-track product is fantastic. It's time for us to control our message, tell our stories, and bring the new fans out. We are in it for the long haul. There are no discussions with CART. That is not on our table. It will not be on our table."
No matter the rift, open-wheel drivers see the Indy 500 for what it is: A marquee event in the United States. "It's still for me a very prestigious race and a title that I would like to add to my curriculum before I stop racing," says de Ferran. "It means a lot to me, particularly the fact that I am going there with Marlboro Team Penske, which has a great history at the Indianapolis Motor Speedway."
Sources: IRL/IMS Public Relations, IRL Technical Dept., IRL race teams, Firestone, Oldsmobile, Nissan.