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Home
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| After
winning four motorcycle world championships in the 1980s,
"Steady Eddie" Lawson
turned to superkarts for kicks.
"The sports car guys look down on us, but we're way
faster."
Photograph by John Rettie
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By Preston Lerner
February 2004
11 |
Whereas in the United States
go-karts are generally dismissed as toys, in Europe and South America they've long served
as stepping-stones to careers in auto racing. For many years, the preferred model was a
single-speed, direct-drive 100cc machine that raced on special kart tracks that were much
shorter and twistier than auto-racing circuits. Karts with bigger engines -- the first
generation of superkarts -- were introduced in Europe in 1969, but their popularity waned.
Then, about 15 years ago, in the never-ending quest for speed, enterprising karters in
southern California started stuffing motocross engines and gearboxes into their chassis.
These 125cc shifter karts were such a hit that it was just a matter of time before
somebody decided that bigger was bound to be even better.
But the twin-cylinder 250cc shifter karts that resulted proved too powerful for kart
tracks. Moving to full-size car circuits was a no-brainer, but the higher speeds achieved
on these longer racetracks spotlighted several deficiencies in existing kart chassis: The
short wheelbase made the machines diabolically twitchy, and their width added scads of
drag. As a result, the Commission Internationale de Karting, based in Switzerland,
developed a formula for 250cc shifter karts designed to race on automobile circuits, and
the modern superkart was born. Superkarts have longer wheelbases than conventional karts
(for better stability through high-speed corners) and heavier minimum weights (to promote
more robust chassis), and they are narrower (to generate higher straight-line speed).
In many respects, a superkart is a car writ small. One fundamental difference is that
superkarts don't have springs to suspend the wheels or shock absorbers to dampen them.
Instead, the chassis serves as the suspension. While a lot of racecars are built around
carbon-fiber tubs designed to minimize chassis flex, kart frames are still welded together
the old- fashioned way out of steel tubing, because a certain amount of chassis flex is
required. Driver flex, too, is par for the course.
"One thing that makes the racing experience so exciting is that you feel like you're
part of the kart," says J.R. Osborne, a 36-year-old real estate developer and
ex?Formula car racer who drove 26 hours straight from his home in Denver to make the race
at Laguna Seca. "The downside is that karts are much more extreme than cars, much
more violent," he adds, referring to the formidable G loads and molar-rattling
vibration. "If the track is too rough, you literally can't see."
The other big point of departure between automobiles and superkarts is the powerplant. The
four-stroke engine technology that is found in virtually all street cars is used mostly in
slower karts. The hot setup is a two-stroke engine. That's right, the annoyingly whiny,
smelly, smoky buzz-boxes that power many lawnmowers, chainsaws, dirt bikes, even
radio-controlled model airplanes. Two-strokes spew out a lot of pollutants, suck down a
lot of fuel, and don't last very long. But they sure go like stink.
For example, Lawson's Yamaha TZ250 develops 90 horsepower from a 250cc engine: That's 360
horsepower per liter. A stock Corvette makes less horsepower -- 350 -- out of close to 6
liters. Even Jeff Gordon's Nextel Cup stock car produces only 130 or so horsepower per
liter. And with the Yamaha engine shoehorned into a container not much larger than a
breadbox, Lawson's superkart boasts a power-to-weight ratio better than virtually every
production car in the world short of the $670,000 Ferrari Enzo.
A
two-stroke engine is less-is-more philosophy in motion. A
cylinder in a four-stroke requires two revolutions of the
crankshaft to complete its four distinct cycles -- intake,
compression, combustion and exhaust. In two-strokes, intake
and compression are combined in one cycle and combustion and
exhaust in another, so each cylinder produces power with
every revolution of the crank. Also, two-strokes don't have
conventional intake and exhaust valves, which means they
don't need camshafts to actuate a complicated (and often
fragile) valvetrain cylinder 250cc two-strokes, some of
which spin faster than 13,000 rpm. Typically, an extra
carburetor jet
Top-of-the-line superkarts are motivated by
twin-
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enhances top-end
performance, while the exhaust port stays closed longer at slower speeds to produce
low-end grunt. Special attention is paid to the shape of the exhaust pipe, which is
technically known as an expansion chamber. "You can put on bigger carbs and you can
run higher compression," says longtime engine builder Sandy Rainey, Wayne's dad,
"but the pipes are where most of the power comes from."
Superkarts stop as well as they go, thanks to disc brakes front and rear. (Frankel
fabricates Lawson's rotors out of an aluminum-based metal matrix compound to save weight.)
They also generate oodles of mechanical grip through wide, treadless tires.
Aerodynamically, though, superkarts are relatively primitive, because the drivers must
punch a huge hole in the air. (Sure, you can run fully enveloping bodywork, and some
racers have, but that's problematic too -- "It stiffens the chassis too much,"
says Paul Owens.) Still, superkarts are very sensitive to aero tuning. The standard
practice is to adjust the nose of the kart, lowering the ride height to increase
downforce, and balance the aerodynamics by trimming the angle of the rear wing.
A good superkart costs about $15,000; figure 30 grand for one with every option known to
man. It ain't cheap, obviously, but it's a bargain by motorsports standards. "I hate
to say it, but it comes down to ego," says Randy Taylor, 47, an American Airlines
Boeing 767 pilot who's another car racer turned superkart fanatic. "If everybody had
zero ego, everybody would be racing superkarts."
Forty-nine superkarts stream onto the track Sunday morning, forming what appears to be a
long, multicolored snake as they buzz around on their warm-up lap. By virtue of winning
yesterday's prelim, Lawson starts the race from the pole -- the inside position of the
front row. But when he sees the green flag and floors the throttle, his Yamaha sputters
and his kart bogs down. (He finds out later that the fuel line had come loose, allowing
gasoline to spray out.) White, a 125cc-shifter-kart ace, surprises everybody by barging
into the lead, and he, Lawson and Owens run in feisty formation. Then Owens slices past
both of his rivals with a bold move, and White falls back as his engine loses power.
Owens leads despite another gearbox problem. Lawson can't take advantage because every
time he buries the gas pedal, his engine stumbles. He resorts to feathering the throttle,
which compromises acceleration and top-end speed, so he makes up for it by pushing harder
in the corners. Racers often rate their effort in terms of tenths, with nine-tenths being
an aggressive race pace and ten-tenths a banzai lap. As he and Owens scythe through lapped
traffic, Lawson's going eleven-tenths. At one point, he draws alongside the Brit, but
Owens hangs tough, and Lawson can't make the pass stick.
With two laps to go, Lawson's kart runs out of gas and rolls to a stop at the end of the
front straight. By this time, Payart is second, but he's too far behind to challenge for
the lead. Owens wins by 17 seconds. Back in the paddock, he's hailed like a conquering
hero. His father hands him a cellphone; his brother is calling from England to
congratulate him. Owens pronounces himself well satisfied. "Eddie Lawson has never
ever been beaten -- until now," he says.
Over in the Lawson pit, the atmosphere is surprisingly upbeat. Rainey is stoked after
finishing fourth after a race full of slicing and dicing. And Lawson is pleased with his
performance even though he's disappointed by the result. "If I'd had a wide-open
throttle, I think I would have had (Owens) covered," he says. "After all, we
were quickest through the whole weekend. Then again, if my aunt had balls, she'd be my
uncle."
Owens may be king for a day, but Lawson's got nothing left to prove. He's out here
strictly for grins, and for a racer, life doesn't get much better than Laguna Seca in a
superkart. "Try one yourself," he says, "and you'll know what I mean."
Preston Lerner, a contributing writer for Automobile,
races his own Nissan 240SX
in amateur events. He's looking forward to his next chance to drive a superkart, as soon
as his bruises heal.
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