How Champ Cars Work

Modern Champ Cars are defined by their chassis. All Champ Cars share the following characteristics:

The chassis of a Champ Car is an amazing thing -- formed almost completely out of carbon fiber and aluminum honeycomb, a Champ Car chassis is extremely strong and lightweight. The entire chassis of the PacWest Motorola car weighs only about 1,000 pounds (455 Kilograms) when it arrives from the factory. The team then begins mounting things like the engine and electronics onto the chassis.

The chassis for the Motorola PacWest car is made by Reynard in England. Reynard supplies the chassis for a number of the teams. Other teams use chassis from Lola. Every year, the manufacturers release a new chassis and all of the teams start from scratch, attending testing sessions to try to gain a competitive advantage with their new chassis.

One reason that a new chassis comes out every year is because the rules evolve with each season. For example, in 1999, the CART rules reduced allowable aerodynamic downforce by 500 pounds, and all of the chassis manufacturers took this rule change into account in their designs. (The Information section of the CART Web site contains the complete rule book for Champ cars.)

When it arrives from the factory, the chassis comes complete with the body of the car, the suspension, the steering system and the transmission, and is called a rolling chassis. The team's job is to add things like the engine and electronics to the rolling chassis and tune it to the driver's style for maximum performance.

All Champ Cars have similar components:

The Motorola PacWest team uses engines supplied by Mercedes-Benz. Ford, Honda, and Toyota also supply engines to other teams.

One incredibly interesting characteristic of the chassis is the fact that the engine and transmission are actually a part of the chassis -- they are known as stressed members. You can see that the only thing connecting the tub to the transmission and rear wheels is the engine, and the rear wing bolts directly to the transmission.

The chassis of a Champ Car as described here weighs approximately 1,110 pounds (500 kg). Adding the engine and other components brings the weight up to the official 1,550 pound (700 kg) running weight for a Champ Car. At race time, the driver and fuel bring the car's total weight to between 1,900 and 2,000 pounds (860 to 910 kg).

The Aerodynamics

One of the most important features of a Champ Car is its aerodynamics package.

The most obvious manifestations of the package are the front and rear wings, but there are a number of other features that perform different functions. A Champ Car uses air in three different ways:

One thing that you can see by looking at them -- Champ Cars definitely are not streamlined, aerodynamically perfect vehicles. You've got the wheels and suspension system sitting out in the open, the huge wings grabbing the air and converting it into downforce, the vents and protrusions on the body, and even the driver's helmet sitting out in the slipstream! It takes a great deal of power to overcome all of this drag, and that's one reason why Champ Cars need such amazing engines.

One part of the aerodynamics package that is not visible is underneath the car. A single carbon-fiber panel covers the entire underside and provides a completely smooth surface for the air to flow past. There are two air tunnels formed into this panel, underneath the two side pods. The tunnels taper so that the Bernoulli effect creates suction underneath the car. Both the wings and these tunnels contribute to the downforce.

The front and rear suspension of a Champ Car is known as a double-wishbone suspension. This type of suspension has the advantages of light weight, impressive strength and a well-controlled ride. The racing surface can be surprisingly bumpy -- for example, at the Cleveland track the surface changes several times along the course, with a bump at each transition. The purpose of a Champ Car's suspension is to keep all four wheels glued to the track despite these aberrations in the pavement.

A Champ Car's suspension also has to be lightweight and compact. The front suspension consists of the triangular supports (wishbones) that mount to the front hubs, along with the springs and shocks. The springs and shocks, as well as the equivalent of the anti-roll bar, are all mounted on top of the car just in front of the driver.

The rear suspension is similar to the front. The main differences are the lack of the steering mechanism, the addition of the drive shaft and the greater weight that the rear suspension must carry. The springs and shocks follow an arrangement similar to the front suspension, but they are larger and fold alongside the transmission.

An important part of tuning the car for maximum performance is done in the suspension. The team controls the toe-in and toe-out of the tires as well as the positive or negative camber of the tires and the caster. These settings help adjust understeer and oversteer. The team can even shorten and lengthen the wheelbase by changing the wishbones!

Because the suspension components are so important to the reliability of a car and its ability to travel in a straight line, CART rules are quite specific on how they must be built. For example:

As you can see, the center of the car is perhaps 2 to 3 centimeters off the pavement. The suspension system therefore does not need to offer tremendous up/down movement. With less than 1 inch of up/down travel available, the ride can get extremely stiff.

The tires on a Champ Car are incredibly important -- they keep the car on the track and translate the driver's inputs from the steering wheel, brakes and accelerator into reality. Especially in the street course events, the driver continually tests the boundaries of tire adhesion -- the limit to how fast the driver can accelerate, brake or take a corner is determined ultimately by the tires.

To handle the incredible forces applied to them, the tires of a Champ Car are much different from the tires you find on your car.

The three biggest differences are:

Between the size of the contact patch of a Champ Car tire and the softness of the rubber, the tires have incredible adhesion.

The tires on a passenger car are meant to last 40,000 to 60,000 miles, while the tires on a Champ Car are designed to last 60 to 70 miles! The CART rules allow a racing team to use up to 60 tires during a 500-mile race.

Besides the incredibly soft rubber used on the surface of the tires, the other thing that makes Champ Car tires last for such a short period of time is the fact that they are very thin. Rubber conducts heat well and retains heat, so the tires have a very small amount of rubber on them to avoid heat build-up. If the driver locks a tire just once during hard braking, it will create a noticeable flat spot on the tire and expose the tire's cords, severely affecting the tire's performance. This limitation is especially important during qualifying, because each team only gets two sets of tires for qualifying runs.

Firestone provides all of the tires for all of teams at every race and practice session. The teams bring their rims to the Firestone area in the race paddock, where technicians mount and balance the tires.

Given that there are 25 cars and each team gets as many as 60 tires per race, Firestone is mounting up to 1,500 tires per event!

This small cylinder, which is mounted on the rim opposite the valve stem, contains a 0.25-watt, 900-MHz radio transmitter and a centrifugal switch. Once a tire starts spinning, the radio is activated and begins transmitting the tire's pressure to this antenna, located just behind the driver's head:

All four tires transmit separately. If the driver runs over something (like debris from a wreck), he can talk to his pit crew, and they can check the tires immediately to see if any of them are leaking using the telemetry stream from the car (see the section on telemetry for details).

The teams pay a good deal of money for this peace of mind -- each tire's radio costs thousands of dollars, and each of the teams' 60 rims needs to have one! That gives you a good idea of how important the tires are.

The CART rules specify everything about the tires and the rims. Here are some of those specs:

The rims are tested by X-ray and dynamic tests before they are allowed on the race course.

A Champ Car is essentially a rolling computer. On both of the air tunnels for the radiators you will find an assortment of many different electronic subsystems.

For example, in the photo below (the driver's left) you can see:

The role of the computer has grown significantly over the last 10 years. The engine is now completely controlled by computer (if this computer goes out, the engine will not run). Among other things, the ECU controls:

Each team outfits its car with a sophisticated data logging system, as well as a telemetry system able to transmit data from the car to the pits in real-time. Each team has at least one member affectionately known as the DAG -- the Data Analysis Geek -- whose specific role is to pore over the reams of data a car produces during a practice run or a race and help the team use that data to maximize the car's performance.

A typical data-logging computer is capable of measuring 200 different parameters of the car while the car is in motion. The data logging system can also transmit 72 channels of data back to the pits in real-time. All 200 parameters are also stored onboard for later downloading. The team can connect a laptop to this jack, located under the rollbar, to download the car's stored data into a laptop computer:

Some of the many signals that the logging systems record include:

Track location is measured in two ways. At four points along the track there are infrared beacons. Each car has an infrared sensor to detect the beacons. When the car passes the beacon, the car sends a signal back to the pit; this allows the team to record accurate timing splits around the track. The team can also use the car's accelerometers as an inertial navigation system to plot the position of the car around the course.

One of the hidden aspects of Champ Car racing is the radio system used both in the car and all around the race course. At a typical race there are several thousand one-way and two-way radios sharing the airwaves! They transmit data from the car and the driver, allow the teams to communicate with one another and even let the tires transmit their pressure to the onboard data computer! A typical car has as many as eight radios in operation at any one time:

A car sprouts antennas to handle all of this wireless communication:

At CART events, Racing Radios supplies the radios that CART officials, series marketing and management staff, medical staff, safety workers and support staff use. They use Motorola equipment exclusively, and it is set up in an amazing variety of systems. The teams are responsible for their own equipment, and many enlist the help of Racing Radios for purchasing equipment, service and accessories. Here's a typical example:

Each team will have this arrangement for everyone in the pit area and the driver. Teams will normally also reserve a frequency for the team's hospitality group (which provides food and such to team members and the team's guests) as well as to the team's marketing group. A typical team will have 50 to 75 radios.

On separate radio frequencies there are other groups as well. For example, CART officials use approximately 250 radios. Race control uses radios, as do the people who are working for the track. Medical crews, fire safety crews, wreck cleanup crews, etc. are all using radios. This is why, at any race, there can be upwards of 3,000 Motorola radios consuming hundreds of allocated frequency bands. Racing Radios coordinates all of the frequencies so that all of the teams have a clear channel during the race, and also handles all of the licensing with the FCC (Federal Communications Commission) for each event.

In addition to all of this voice communication, the car is also transmitting telemetry data back to the team and to CART (for example, to supply data to the telemetry board). Each tire on every car also has its own small, 0.25-watt radio to transmit pressure data to the car's onboard data logging system. The tires and the cars transmit in the 900-MHz band, with the car using spread spectrum techniques to improve reliability and reduce problems with interference.

Also, some cars now have an in-car television camera (sometimes more than one) that transmits real-time images back to the television network for broadcast to viewers so they can see the driver's perspective.

With all of these radios transmitting, the big problem is finding a set of clear frequencies that keep everyone separated and are also free from outside interference. This problem gets even worse when the race course is near a city, where the frequencies are already crowded with city services like police, fire and sanitation, as well as industrial radio users. Racing Radios is in charge of finding clear frequencies for everyone prior to the race and then assigning the frequencies to each team. Racing Radios also needs to keep all of the radios charged, so there is a tractor-trailer devoted to charging equipment and distributing all of the radios.

During the race, scramblers are not permitted. All communication is therefore available to anyone with a radio scanner, and many fans and reporters bring scanners to each race to get more detail on what is happening.

One of the more interesting features built into a Champ Car is a set of three pneumatic jacks that are integrated into the chassis.

There are two jacks up front and one in the rear. By connecting a pressurized nitrogen hose to a port located behind the driver, the pit crew can jack the car up in less than a second when the car stops in the pit.

The integral jacks speed up the pitting process, reduce the number of people who have to go over the wall for the pit stop, and eliminate a piece of equipment that the crew would have to carry over the wall.

The engine is obviously a central part of a winning Champ Car. The engine must be powerful, lightweight and reliable. During a race, the engine is exposed to incredible stress, so the engine is replaced after every race. Engines are also replaced after a day of practice or a qualifying run. The Motorola team uses dozens of engines each season.

As described in the section on the chassis, the engine is also a part of the car's structure. The engine sits behind the driver, between the transmission and the tub that forms the cockpit of the car. It is the only connection between the front and back of the car. The engine is therefore called a stressed member, meaning that it carries load and is subject to mechanical stress. The level of stress that a Champ Car can exert on the frame is one more thing that makes the engine so critical to success -- the engine is, mechanically, the entire midsection of the car's structure!

The engine and drive train of a Champ Car make up about one-third of the mass of the car. In a severe crash, the engine and drive train assembly separate from the front of the vehicle at a line just behind the driver in an attempt to protect the driver and dissipate energy.

The specs for the Mercedes-Benz engine that the Motorola team uses include:

A Champ Car engine is obviously very different from the engine you find in a normal car. Here are some of the things that make it unique:

The engine gives a Champ Car some amazing capabilities. For example, a Champ Car can accelerate from zero to 100 mph in about five seconds, and is still in second gear at that point! For comparison, a Corvette or Viper can accelerate to about 65 mph in the same amount of time.

All Champ Car engines use a turbocharger to improve their performance. The turbocharger pressurizes the air flowing into the engine's cylinders so that the engine can burn more fuel during each stroke. The extra fuel means extra power per stroke.

A Champ Car engine runs with a turbo boost of 40 inches (about 19 PSI). When the turbo over-pressurizes things, a pop-off valve releases the extra pressure.

Pop-off valves are now electronic. When they release, they are loud enough for the driver to hear, so the driver knows it is happening.

One of CART's more interesting roles is the certification and distribution of pop-off valves. Here is CART's description of the valves from the CART Web site:

Any CART racing team has a rather interesting relationship with its engine manufacturer. The team signs a contract and leases a season's worth of engines from the manufacturer. The manufacturer supplies a set of complete engines (the number may vary depending on the contract, but a typical number might be six), which the team uses in a rotation. After each race, the team sends the used engine back to the manufacturer to be rebuilt.

Because of this relationship, the team actually has nothing to do with the engine beyond mounting it in the car, adding oil, installing the spark plugs and starting it up. If there is any sort of problem with an engine, the team replaces it with a new one and sends the old one back to be rebuilt.

Unlike the engine, the transmission of a Champ Car is something that the team is intimately familiar with. The team rebuilds the transmission and can change the gear ratios depending on the track.

The Motorola team's transmission is supplied by Reynard along with the chassis. The transmission is built by Xtrac, a very well-respected transmission company in many areas of automobile racing.

A Champ Car uses a six-speed sequential transmission that is more similar to a motorcycle's transmission than to a typical automobile's. Shifting is done by the driver using a small lever to the right of the steering wheel:

Another feature of a Champ Car's engine and transmission is called Shift Without Lift, or SWOL. The engine control unit allows the transmission to shift gears without the driver lifting off the accelerator. The driver can therefore upshift without using the clutch or letting off the gas, and this maximizes acceleration. The SWOL feature is also available during downshifting, but the driver must match engine rpm with the gear choice during the downshift.

Champ Cars burn methanol fuel. Methanol is a form of alcohol and has several advantages over gasoline in an engine:

The only significant problem with methanol is that it burns with an invisible flame -- you cannot see a methanol fire. People don't know that they are near a methanol fire until they feel the heat. This includes the driver, who in a crash may have methanol spilled on his suit. The driver will therefore move flagrantly once he has detected a fire to let other people know that there is a problem.

The car carries 35 gallons (142 liters) of fuel in a fuel cell located behind the driver. This cell is made of a flexible Kevlar and polymer material -- it is more like a bag than a tank. Inside the bag is a sponge-like substance that gives the bag its shape. The bag is designed to withstand a crash without rupturing -- rather than rupturing, it flexes and changes its shape. The idea behind the sponge is to hold the fuel so that, in a severe crash, it does not spray over the driver, other cars or the track.

The engine burns methanol at a rate of approximately 2 miles per gallon, meaning that the car must make a pit stop for fuel approximately every 70 miles or so. During a pit stop, the fuel pours into the cell through a large filler mounted just behind the driver. Thirty-five gallons of fuel can flow into the cell in just a few seconds!

CART rules allow each team to use fuel at a rate of up to 1.8 miles per gallon. That is all the fuel that the team gets, so each team must manage its fuel consumption to work within that limitation.

Once the team receives the chassis from Reynard and the engines from Mercedes, the team assembles the car. The team and the driver then begin the season-long process of tuning the car. The team has intimate control over many different aspects of the car's setup, including:

The goal is to adjust all of these variables in concert with one another to create the perfect setup. Obviously this is not easy because all of the variables have interrelationships with one another. Getting the car tuned and keeping it in a state of perfection are two of the team's most important tasks during the season.

A big component in the tuning process is the data gathered by the car's telemetry system. The team can adjust things and then look for changes in the car's performance in the data that the car's sensors gather.

In Champ Car racing, the car and driver are one. Both must deliver peak performance in order to win.

The driver for the Motorola PacWest Racing Team is Mark Blundell.

Mark has had a long and winning racing career. He was born in England in 1966. At age 14, he began with motocross. He was a Top 36 national rider, winning many regional championships and accumulating 196 trophies. In 1984, Mark won the British Formula Ford 1600 Junior Championship. During the season he had 25 victories, 24 poles and 21 lap records.

In 1985 Mark began his professional driving career. By 1991 he was driving Formula 1 cars in Europe, with 14 Grand Prix starts. In 1992 he won the Le Mans 24-hour race with the Peugeot-Sports Team.

The 1996 season was Mark's rookie year in U.S. Champ Car racing. He finished third in Rookie of the Year points, and has been driving for Motorola ever since.

The driver's interface to the car is the cockpit. The cockpit environment is customized to the driver, but also has a number of features that are shared by all Champ Cars.

The first thing you notice when you get into a Champ Car is the tight fit -- it feels almost like you are "wearing" the car. The cockpit wraps around the driver and holds him in. The fit is so tight that you have to remove the steering wheel to get in and out of the car. The reclining seat that the driver sits in is custom molded to his body, and the position is more like lying on your back than sitting. The driver is then strapped in with a wide, five-point harness:

As shown in the figure, the buttons give the driver access to the following features:

LEDs on the steering wheel indicate:

The LCD display complements the LCDs on the dash. These displays feed the driver information from the engine and the car's sensors.Champ Cars have sensors everywhere, so there is plenty of information available to the driver.

At the driver's feet are the accelerator, brake, and clutch pedals, arranged as they are in a normal car.

Driving a Champ Car is nothing like driving a normal automobile. Here are some of the things that you notice:

During a race, the driver is constantly thinking about what is coming up. A driver's brain is multi-tasking -- part of it is handling the current situation on the track, keeping spacing, adjusting speed and turning. (This is much different than normal driving -- these race cars are often within inches of one another and the pack is moving at incredible speeds.) The other part of the driver's brain focuses on what will happen in the next section of the track. The driver plans exactly what he will do, and then executes it when he arrives at that section. At that point, he is thinking about the next section of the track, and so on. In all this planning, the driver factors both the car he is trying to catch and the cars that are trying to catch him -- a driver is always trying to pass the car in front and trying to defend against being passed.

Equipment and Training

During a race a driver wears:

The helmet is one of the most important parts of the ensemble because it becomes a part of the exterior of the car. In an open-cockpit Champ Car, the driver's helmet is out in the 230-mph slipstream of air rushing past the car. In the photo you can see a variety of vents and indentations designed to help cool the driver and prevent buffeting. As the air flows past the helmet, it needs to have smooth flow lines -- any turbulence causes the driver's head to shake in the slipstream (affecting both vision and stamina).

Champ Car driving is a demanding sport that requires precision, incredibly fast reflexes and endurance from the driver. A driver's heart rate typically averages 160 beats per minute throughout the entire race. During a 5-G turn, a driver's arm -- which normally weighs perhaps 20 pounds -- weighs the equivalent of 100 pounds.

One thing that the G forces require is constant training in the weight room. Drivers work especially on muscles in the neck, shoulders, arms and torso so that they have the strength to work against the Gs. Drivers also work a great deal on stamina, because they have to be able to perform throughout a three-hour race without rest.

One thing that is known about Champ Car drivers is that they have extremely quick reflexes and reaction times compared to the norm. They also have extremely good levels of concentration and long attention spans. Training, both on and off the track, can further develop these skills.

Motorola (the sponsor) contracts with the PacWest Racing Group (the team) to manage and maintain the crew, the car and the driver. The PacWest Racing Group actually manages two complete cars for different sponsors. In 1999, there were 17 teams managing the cars that race in the FedEx Championship Series.

The PacWest Racing Group has been a CART competitor since Bruce R. McCaw formed the team in 1993. The group had its most successful CART campaign to date in 1997 when Mark Blundell and his teammate combined for four race wins, three pole positions and finished sixth and fourth, respectively, in the Championship. Mark also won the closest race in CART history -- by only 27 thousandths of a second -- at Portland.

McCaw had an illustrious business career prior to forming the PacWest Racing Group. He founded an aviation insurance company, a regional airline and, with his brothers, a cellular phone company that AT&T purchased and now operates as AT&T Wireless.

The PacWest Racing Group consists of 72 people who are based in Indianapolis, IN (you can take a shop tour). The team is a complete business, so it includes a wide range of people: vice presidents, directors, managers, engineers, technicians, mechanics, and so on, both on the racing and the business/marketing sides. The PacWest Racing Group is responsible for everything from the aerodynamics of the car to what the team's guests will eat on race day!

The part of the team that you see on race day is the group of specially trained people who work in the garage and the pits. They are intimately familiar with the car and work closely with the driver in their attempt to create a winning combination.

For the team, the season starts in November with the arrival and assembly of the chassis and engines for the new season. The team starts testing in January and February. Racing starts in March and runs on roughly a bi-weekly schedule through late October. Although most Champ Car races take place in the United States, several of the races are international (Australia, Canada, Japan, and Brazil).

All of the work, training and preparation lead up to one thing: race day! On the day of the race, the team hopes that everything with the car and the driver is perfect and that the result of all of this preparation is a win.

Races normally occur on Sunday, and there are 20 races in a season occurring approximately every two weeks (see the the CART page for a complete calendar).

The team typically arrives at the track on Wednesday evening or Thursday morning. To get to a race, the team packs up the cars and a complete mobile shop into tractor trailers and drives (or flies, in the case of international races) to the event:

The rig holds two cars, spare engines, various parts and tools and all of the equipment necessary to repair any problem that might occur.

The team unpacks everything into the garage at the track, and the mechanics get to work preparing the car on Thursday. On Thursday evening, there is a technical inspection of the car, checking the weight, measurements, safety features and so on. On Friday, there are practice sessions in the morning and afternoon, as well as provisional qualifying if the race is being held on a road course. Saturday is reserved for practice in the morning and qualifying in the afternoon. The actual race occurs on Sunday.

A big part of the race is the pit stops. Each team is assigned a slot on pit row, as shown below:

A pit stop is a choreographed, high-speed event designed to service the car as quickly as possible. During a typical stop, the team will load 35 gallons of methanol into the car, replace all four tires and adjust the angle of the front wing. The team trains for months, both with the car and in the weight room, to get ready for this level of performance.

Motorola's Role

Motorola is an interesting company to use as an example because Motorola's role in Champ Car racing has four distinct parts:

Motorola is the "Official Communications Hardware of CART." Motorola wireless communications equipment helps keep safety workers, medical personnel, teams, drivers and the CART operations staff in constant communication. The fast-paced, high-technology environment of Champ Car racing is a perfect proving ground for Motorola products. It is interesting to note that the wireless equipment used by CART, the teams and the support staff is the same wireless equipment that consumers purchase worldwide for individual use.

Working with organizations such as Racing Radios, Motorola helps provide communications to most of the Champ Car teams along with the Pace Car Program and individual tracks. Racing Radios experience combined with Motorola products forms the backbone of the communication infrastructure on the track -- there literally could not be a race without it.

Sponsors are vital to all major forms of automobile racing. The sponsors provide the capital that supports the teams and allows them to race. Without the sponsors there would be no teams, and therefore no racing.

Sponsoring a Champ Car is not an inexpensive proposition. There are many different levels of sponsorship and the teams work in different quality brackets. At the low end, a sponsor can form a syndicate and pay on the order of $250,000 or $500,000 to be one of the sponsors of a multi-sponsor car. At the high end, an exclusive sponsorship can exceed $10 million per year. In return, the sponsor's goal is to get exposure for the company's name. The car, the banners on pit row and other types of signs let millions of TV viewers and fans at the track see the sponsor as a part of Champ Car racing.

Beyond the exposure that motorsports provides for Motorola, they use their program to develop business relations with customers and consumers, and to develop business-to-business opportunities and partnerships. Motorola also uses motorsports to increase brand awareness to an extremely large global audience that has proven to be brand loyal to sponsors supporting motorsports as a whole. Additionally, with CART being a global series, Motorola has the ability to participate with all of their global customers, business units and sectors to develop programs and promotions worldwide.

Sponsorship of a Champ Car works well for Motorola. The exposure the company gets is associated with a high-tech, exciting sport that makes extensive use of two of Motorola's major products -- radios and microprocessors.

The company feels that it gets a very good return on its investment.

For more information on Champ Cars and related topics, check out the links on the next page.