Eyeball-rattling grunt and cars launched by the hand of God: Drag racing is one of the most awe-inspiring things on wheels. Wired.com's Chuck Squatriglia recently took a closer look at Top Fuel racing — the pinnacle of the sport. —Ed.
There is nothing subtle about drag racing.
It is a sport of extremes, from the unconscionable amounts of fuel consumed to the unfathomable amounts of power produced to the ungodly sums of money spent in the singular pursuit of maximum acceleration.
Nowhere is this more obvious than on the starting line, when two top-fuel dragsters unleash 8,000 horsepower apiece. Standing behind them is like opening the gates of hell. The air roars. The ground shakes. Noxious fumes wash over you. The cars streak toward the horizon as if thrown by the hand of God.
Top fuel is the pinnacle of drag racing. Even in a sport where success is measured in thousandths of a second, everything in top fuel happens in a blink of the eye. The best drivers can do the quarter-mile in around 4 seconds. They experience about 5 times the force of gravity. And they reach the far side of 300 mph.
As amazing as it is to witness, it is even more so to experience.
"There is no way to describe it. None," Dave Grubnic, the 48-year-old driver of the Kalitta Air top-fuel dragster, told us during the Fram Autolite NHRA Nationals at Infineon Raceway earlier this month. "When you hit that throttle, everything in your immediate field of vision is gone. Just gone. You do zero to 100 mph instantly."
Grubnik's exaggerating. It actually takes about eight-tenths of a second.
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Photos by Jim Merithew/Wired.com.
The seeds of American drag racing were planted in the 1930s on the dry lake beds of the American West. But the sport as we know it didn't really take off until after World War II. A lot has changed in the 57 years since National Hot Rod Association held its first official race on a parking lot at the Los Angeles County Fairgrounds. But the objective remains the same: Reach the other end of the strip as quickly as possible.
To do that, top-fuel dragsters produce insane amounts of power and torque.
The rules require top-fuel dragsters, and their kissing cousins, funny cars, to run 500-cubic inch V-8 engines loosely based on the 426 Hemi "Elephant Engine" Chrysler built from 1964 until 1971. Everything about the engines is custom built to exacting specs, but beneath it all they're still a push-rod V-8 with a centrally located camshaft and two valves per cylinder.
The engine block and cylinder heads are machined from solid blocks of aluminum. Not because they can be, but because they have to be.
"That's the only way they can make them strong enough," Grubnik said. "Otherwise they'd blow apart."
All engines need three things to run: air, fuel and spark. The engine in a top-fuel dragster simply needs more of it.
A lot more.
The 14:71 supercharger on Grubnik's car runs 45 to 50 pounds of boost and sucks down as much as 3,200 cubic feet of air per minute during a run. The fuel pump can move 95 gallons a minute through a constant-flow injection system. Two magnetos provide spark to the pair of custom-made spark plugs in each cylinder.
The result is an engine capable of producing about 8,000 horsepower and 6,000 pound feet of torque. That's roughly six times greater than the Bugatti Veyron Super Sport, which is, at this moment anyway, the fastest production car on the planet.
Such figures are, like the federal deficit or Google's market cap, are too big to comprehend. All you really need to know is, a top-fuel engine can propel a 2,250-pound dragster from zero to 120 mph in 1.3 seconds.
Getting from 120 to 280 mph takes another 1.7 seconds. The NHRA boasts that a top-fuel dragster can out-accelerate a fighter jet from a standing start. Two seconds into a run, the driver is experiencing as much as 5 times the force of gravity.
"A top-fuel dragster is either on or it's off," Grubnik says. "There is no in-between. It's completely nuts."
Top-fuel dragsters bear no resemblance to anything you might even remotely consider an automobile. Oh sure, they've got four wheels, a steering wheel and an engine, but that's where the similarities end.
The cars are 25 feet long, as stipulated by the rules, and have a wheelbase of no more than 300 inches. They are made of chrome-moly steel tubing and wrapped in carbon fiber bodywork. Grubnik says the rear wing on his car generates 5,000 pounds of downforce at 300 mph.
Massive 14-inch carbon fiber brakes on the rear wheels, along with a pair of parachutes, bring the cars down from speed. When a driver yanks the cord on both chutes, he can experience as much as 7 times the force of gravity.
"When you see a driver out of breath at the end of a run, it's not because of the physical exertion of driving the car," says Jeff Arend, the 47-year-old driver of the DHL funny car campaigned by Kalitta Motorsports. "It's from the stress of going from 5 Gs to minus 7 Gs in about 4 seconds."
Funny cars run the same engines as top-fuel dragsters but package them in smaller cars with a wheelbase of 125 inches wrapped in full bodywork. They're loosely based on production cars, although Toyota has never, ever built anything like Arend's Toyota-bodied car.
Unlike a top-fuel dragster driver, the guy at the wheel of a funny car sits behind the engine, which, coupled with the shape of the body, makes visibility a challenge. Arend says funny cars also are harder to drive.
"They've got the same power as a top-fuel dragster, but they're shorter," Arend says. "A top-fuel dragster only wants to go in a straight line. A funny car wants to do anything but go in a straight line."
Top-fuel dragsters run on a mix of 90 percent nitromethane and 10 percent methanol, although the mix can change depending upon conditions. Whatever the ratio, the fuel economy of a top-fuel car is best measured in gallons per mile.
They'll suck down three gallons a minute at idle and as much as 1.2 gallons a second during a run. A typical car will consume 12 gallons of fuel –- at about 16 bucks a gallon –- during the burnout, staging and run.
The fuel flows through a 2.5-inch line at up to 400 to 500 psi. Most of it is wasted, because the engines aren't terribly efficient.
"You're lucky to get 30 percent efficiency," Grubnik says. "We're throwing 70 percent of the fuel out of the exhaust.
That's why smart fans bring gas masks.
Engines are stripped to the billet-steel crankshaft and rebuilt after every run. A skilled crew of seven mechanics can do the job in an hour or so, but if all hell breaks loose they've been known to do it in half that.
The forged-aluminum connecting rods and pistons along with the exhaust valves, spark plugs and clutch discs are replaced after every run. Everything else gets a thorough inspection and is yanked if there's any doubt as to its integrity or reliability. Once reassembled, the engine is filled with 13 quarts of 70-weight oil.
It's a huge undertaking, which is why Kalitta Motorsports — founded and led by racing legend Connie Kalitta — uses five trucks to haul three cars, seven spare engines and enough parts to build a car from scratch if necessary.
Exhaust valves are a single-use item. They're often made of nickel metal alloys and typically measure about 2 inches. Intake valves are titanium and measure about 2.5 inches.
Cylinder heads also are rebuilt after every run. The heads are milled from billet aluminum and don't have water jackets, because they're cooled by air and fuel. The headers can reach 1,800 degrees Fahrenheit during a run, and you'll often see them shooting flames, as raw fuel is fired from the pipes.
A single cylinder of a top-fuel engine produces more power than an entire NASCAR engine, and Arend says each exhaust pipe generates 250 to 300 pounds of down force with each pulse.
That's why a car will careen to one side when the engine loses a cylinder.
All the power in the world doesn't mean a thing if you can't get it to the ground, which is why the engine is but one part of the equation.
"People think these cars are one big engine," says Jon Oberhofer, one of Arend's two crew chiefs. "They're not. They're one big clutch."
Top-fuel cars don't have a gearbox. They use a multistage clutch that uses timers to gradually transmit power from the engine to the rear axle.
"About 2.5 seconds into the run is where you get full power and full torque," says Jim Oberhofer, who is Jon's brother and Grubnik's crew chief. "You're trying to get the car to the eighth-mile mark as fast as you can, because from the eighth-mile to 1,000 feet, your power starts to fall off."
The quarter-mile hasn't actually measured a quarter-mile since 2008, when Scott Kalitta was killed during qualifying at a race in Englishtown, New Jersey. The NHRA, concerned over the speeds the cars were reaching and the room required to slow them down, shortened the distance from 1,320 feet to 1,000 at most events.
Top fuel cars ride on 17-inch rear tires that are tossed after four to six runs. That works out to about 2 to 3 miles.
If something on the car can be measured, it is. From fuel pressure and cylinder temperature to clutch pressure and atmospheric conditions, it's all logged, tracked and plotted on a graph.
"The data recorder records everything the car did," Grubnik (pictured) says. "It's like the black box on an airplane."
All the info is scrutinized in a relentless campaign to shave another thousandth of a second from a car's elapsed time. Even weather conditions are analyzed in painstaking detail to determine the ideal compression ratio, fuel volume and other factors.
"We use Excel quite a bit," says Jon Oberhoffer.
At 25 feet long and a wheelbase of 300 inches, the Kalitta Air dragster does not exactly turn on a dime. Or even a silver dollar.
The race is often won or lost not at the end of the track, but the beginning. Reaction time is everything. The process starts with a burnout, where the drivers spin their water-soaked tires to clean and heat them to maximize traction.
Drivers line up alongside what's always been known as the "Christmas tree," which uses amber lights to indicate the countdown to the green light that starts the race.
"As soon as we see the amber, we hit it," Grubnik says.
The best drivers need as little as 0.05 seconds to react once the light goes green. Grubnik's best reaction time at the Mopar Mile-High NHRA Nationals on Sunday was 0.068 seconds. His teammate, Doug Kalitta, bested him with a 0.062.
Kalitta won the day's event, beating Brandon Bernstein in the final round with an elapsed time of 3.963 seconds and a top speed of 308.35 mph.
Once the lights turn green, the only thing left to do is hold on.
"It's all instinct," Grubnik says. "All the driver does is start the car, stop the car and keep it in the groove."
"The groove" is the two lines of rubber laid down by the cars that have gone before. The traction is best there, so drivers try to follow the same line.
Grubnik's been keeping it in the groove since he was a 16-year-old kid in Brisbane, Australia. He started out racing a Ford Falcon before he even had a driver's license. He remembers watching nitro-powered funny cars and thinking they were the coolest thing ever.
"What drew me was the power," he says. "The noise, the power, the flames. It was like the needle going in. I was hooked. I told myself that one day I'd drive top-fuel."
This story originally appeared on Wired.com on July 27, 2010 at 8:25 PM EST.