What a Rush
Old tech & new materials intricately combined for insane speed: the ingenuity of the top fuel dragster.
Photographs by John B. Carnett
The violence of the launch was astonishing. Vibration short-circuited my senses, and the acceleration clouted my helmet back against the car’s roll cage. For 200 feet, I couldn’t tell where I was. I’m not used to feeling fear while in a car–I’ve cornered 185-mph Ferraris at top speed–but this dragster scared me. After a couple of runs, they told me, I’d get used to it: The car would go straight for 200 feet until I could see.
For some idea of what it’s like to drive a Top Fuel dragster, take that experience and multiply by 10. My learner car was a 700-plus-horsepower McKinney Super Comp gas dragster from the Frank Hawley Drag Racing School in Gainesville, Florida-plenty fast, with more than Nascar-level horsepower. But it was a go-kart compared with the 6,000-plus horsepower, nitro-fueled dragsters raced by the pros. In the quarter-mile, a Top Fuel “rail” dragster has reached 332.18 mph (the record, set in 2001 by Kenny Bernstein), covering the distance in 4.477 seconds. Moving that fast requires a shotgun marriage of brute power and precarious, finicky mechanical engineering, performed over one of the briefest timed events in competitive sport. Downforce, G-force, parasitic drag, and assorted other manifestations of the violence of this sport must be overcome. A rail’s purposely flexible chromaloy frame is designed to bow upward in the middle like a saw on the track, as carbon fiber and magnesium wings push the front and rear of the car down. The super-soft dragster tires, inflated to just 6 psi, wrinkle elastically at launch, slingshot forward, then, disfigured by centrifugal force, balloon zanily in the heat of the run.
The fastest car-to-car sport in the world, drag racing is also one of the purest expressions of mechanical prowess. Unlike tech-obsessed Formula 1, however, drag racing has never gone fancy. In the fully crowd-accessible paddock, where the air wrenches squeal and the nitromethane fumes flow, fans stand five deep, watching crewmen work on the cars after each run. It’s like viewing open-heart surgery at speed: a full teardown and rebuild of the supercharged 500-cubic-inch V8-new pistons, heads, belts, and whatever else is required-in 45 minutes. Aside from the lightning-fast crews, though, the pit atmosphere is easy. Close your eyes and the party atmosphere of 1950s drag racing returns: flathead Ford V8s and skinny tires, Saturday-night bravado, the guy with the pack of Luckies rolled up in his sleeve. Same now as it ever was: Get from here to there in a straight line fastest, making as much noise and smoke as possible.
Ed “Ace” McCulloch, a champion ex-racer and a crew chief at Don Prudhomme Racing, one of the top team owners, is explaining how he programs his multistage five-disc clutches. Each disc is on a pneumatic timer, and progressive engagement is controlled to fractions of a second. In the old days, a driver dropped the clutch at the start and up-shifted through gears. Today, there are no gear changes in Top Fuel and Funny Cars. Instead, the preprogrammed clutch packs mediate engine power to the wheels with no control from the driver. His job-or hers, for several women are among the drag-racing elite, including Shirley Muldowney, who raced at the age of 62 in Englishtown, New Jersey, this summer-is to “get a good light,” that is, get a quick reaction time when the light turns green on the tree.
“At the light,” McCulloch says, “the engine is turning 8,000 rpm, but the axle ratio is only 2,000 rpm-a slippage of 6,000 rpm. By operating a series of levers-there can be up to 12, but we don’t use that many-the clutch pressure and axle ratio rises incrementally. It doesn’t reach 1:1 until 3 seconds into the run.”
The race, then, is more than half over before the wheels are dealing with the engine’s full power. For 3 seconds, the clutches are being broiled by more than 6,000 horsepower. A half-hour later, they still smoke like ribs on a spit. No surprise that three of the five discs in each clutch must be replaced after every run. The remarkable thing is that a successful team can produce race results within a hair of a previous run-in fact must do so for an official record time to stand in the books, because any record must be backed up at the same event by another run that clocks within 1 percent of the speed.
Engine power is fully preprogrammed as well and matched to the clutch-engagement curve. McCulloch first assesses whether the track is slippery or “tight,” advancing or retarding the car’s cylinder timing and trimming fuel flow to suit. “I can program 12 timing changes in a run,” McCulloch says. “At the start, I use about a 20-degree retard, which knocks the rpm down to 7,700-that ‘relaxes’ the tires, so you don’t get tire shake.” Then McCulloch advances the ignition for more power, until the next clutch engagement, when he retards the speed again to keep from breaking the tires loose. The amount of clutch and retard depends on how slippery the track is as well as on weather conditions like air pressure and humidity. “It’s all,” McCulloch says, speaking about the car, “adjustable.”
The fuel pumps produce 100 psi and flow at a prodigal 85 gallons a minute. At idle, the engine guzzles 13 gallons per minute, but at the peak of the race, when the engine is roaring at 8,000 rpm, this leaps to upward of 70 gpm. Nitro gushes in so violently that, if engine load is momentarily lost due to wheel spin, the engine will “drop a hole”-the twin spark plugs in a cylinder are extinguished by the fuel.
“If the humidity is high,” says Scott Okuhara, one of McCulloch’s numerous crewmen, “we’ll increase the blower speed to push more oxygen into the engine.” When the engine is running at 8,000 rpm, the spin speed of the belt-driven supercharger is about 25 percent higher. “If the fuel-air mixture is a bit wrong and we burn a piston,” adds Okuhara, “that means, besides the new piston, we also have to put in a new bore.”
If all goes well during a run, the engine will be at full power for less than 5 seconds. With the additional burnout before each run-full pedal for a couple of seconds to heat and clean the tires on a watered-down surface-the total full-throttle life span of a nitro engine is less than 8 seconds.
While an onboard computer is used to analyze performance data after a run, tweaking for the next run is analog-strictly mechanical. What’s more, computers are prohibited from controlling engine activities during a race, even though the technology is available now. But the officials and competitors in the sport were afraid that the costs of installing these systems in cars would spiral out of control (look at F1 costs).
Besides achieving a good reaction time, the driver has two additional duties. First, he must stay in the “groove” (the twin black stripes where tire rubber and traction are). Second, he must keep the throttle nailed open-most of the time, anyway. If the timing is bad, a good driver will instinctively let off the gas or hit the brake to prevent the tires from smoking and slowing down the car. At the end of the run, he manually releases the drogue chutes crossing the finish line, sustaining a 4.5-G deceleration load to match the 4.5-G load experienced at launch.
“So just how much horsepower do you need to win?” I ask McCulloch. He grins. “More.”
No one knows exactly how much power these engines produce on nitro. Starting with a custom-built, hugely strengthened aluminum block based on the classic 426 Chrysler Hemi, they are so explosively powerful that putting one on a dynamometer to measure output is unthinkable. The same bored-out 500-cubic-inch engine, running on more benign alcohol, has been dyno’ed, and extrapolations made for nitro. For years, the figure quoted was 6,000 horsepower, but today there is more and more talk of 7,000.
With this much power, keeping the car from flying is serious business. At 300-plus mph, faster than most private planes, a Top Fuel car’s carbon fiber rear wing produces something north of 6,000 pounds of downforce. The front wing brings another 1,800 pounds to the party. The car would pop the mother of all wheelies-a “blow-over”-were it not for the rather dainty-looking wheelie-bar out back.
Legend has it that a hot-rod magazine in the 1950s published a scientist’s article proving that it was physically impossible for a car to accelerate to 150 mph in the quarter mile. The introduction of nitromethane and vastly improved drag tires in the early 1960s opened a new world of speed and thunder. Unlike gasoline, oxygen is built right into nitro-CH3NO2. Gasoline’s C8H18 formula requires a lot of added O to ignite. Nitro actually contains less energy per ounce than gas, but requires only about an eighth as much added air, so a much higher fuel-to-air ratio is possible in the cylinders. By volume, a nitro engine is more than twice as powerful as a gas engine.
Touchy stuff, though, nitro. The strongest engines can explode, and that’s most unpleasant if you’re sitting behind one. Engine and transmission were in front of the driver until the early 1970s, when the transmission in driver Don “Big Daddy” Garlits’ Swamp Rat XIII dragster exploded, cutting the car in two and severing part of his foot. Swamp Rat XIV was the first successful rear-engined rail.
Engines continued to run 100 percent nitro-and continued exploding-until television forced a change. In 1999, the National Hot Rod Association, drag racing’s strongest sanctioning body, had just signed a major TV package when, in quick succession at the Pomona Winternationals, two nitro engines exploded on the line during live coverage. Massive delays needed for cleanup forced the NHRA to mandate a less volatile fuel formula-90 percent nitro and 10 percent alcohol. Engines still grenade, but less often and less exuberantly.
Drag racers may be the fastest competitive drivers in the world, but they’re also among the oldest. Lots of Grecian Formula; very little weight training. Although there is a new generation of drivers, the veterans remember most of the nitro speed records of the past four decades-200 mph, 250, 300, 330-because they were there. Experience counts in this sport, and personality even more. More significantly, drag racing is really quite conservative. Rules and engine types haven’t fundamentally changed since the golden age of the 1960s and 1970s. Speeds have almost doubled since then, but lately the rules have been used to throttle back car performance in the name of safety. For example, one rule allows a minimum final drive ratio of 3.20:1. Don Bender, assistant crew chief on Prudhomme’s Top Fueler car, is clear on the effect: “With a 3.00:1, we could probably go 340.”
Don “The Snake” Prudhomme, the legendary owner of Prudhomme Racing whose driving career began in the late 1950s with the Burbank (California) Road Kings and ended in 1994, smiles. “I loved the old days: working on my car, being all sweaty and pumped for a run. But it’s changed. Today, you need the best crew chief and best sponsor. You need drivers with the right demographics for the sponsor. On the other hand, maybe some of the rules haven’t changed enough. There’s no computer-chip tuning, for instance. But I think that’ll come.”
Not everybody likes that idea, though. For one thing, some aficionados fear that if computers were used during races and to maintain the cars, competitiveness would be compromised, because the teams with the most money would be able to afford the best technology. “What good would it be if you could afford computers and nobody else could,” says Tim Richards, crew chief of Bud King Racing, owned by Anheuser-Busch. “Competitors would disappear.”
After several runs, Frank Hawley’s black Super Comp dragster still scared me, and I was lifting the throttle too soon. After a few more abbreviated runs, Hawley cleared me for the full quarter mile. An experienced driver offered me a few tips, and I was committed. The burnout was fun: full throttle, spinning tires, blue smoke. I rumbled up to the starting line, waited. The green signal came-and this time I resisted the strong urge to ease up. After the violent, head-banging first 200 feet, I used all 700 horsepower straight down the line. This was fun. The skinny bicycle wheels on the front of the car fidgeted like insect antennae as I streaked past the finish line.
I had done 154 mph. Not bad: Hawley said the car would only do 158. But I still had one more run to do and I kept thinking about what that other driver had told me. He had nailed the naked recklessness of this sport. “Drive it like you stole it,” he said. “Drive it like you’re trying to break it.” n
_Ted West is a freelance automotive writer living in the New York metropolitan area. He is working on a novel about professional racing.