Article from
Popular Science February 2004
(Page 2 of 4)


Green Flag
About Superkarts
World's fastest"go-karts"

 Track Vehicle Flag
Superkart Links

Passing Flag
Superkart Videos

Smalldebrisflag.gif (920 bytes)

South Africa

International Superkart

Superkart photos from
around the World

Track Vehicle Flag
Links To Everything Needed
To Race Your Superkart

Passing Flag
Tracks Around the World
Including US tracks

Yellow Flaga
Popular Science Superkart Article
This is a Must Read!

Red Flag
BRC 250F/E

F.P.E. 250F/E


Hemingway 250F/E

Track Vehicle Flag
New Pics Added
Two Seat Superkart

Yellow Flag
Jeff Deskins' Photo Gallery
from Mid-Ohio

White Flag
SKI 2001 WSK Coverage/Photos
Excellent coverage!

Red Flag
Motorcyclist Mag. WSK Article

Rotax Logo
Rotax Dealers

Green Flag
Vintage Karts
How it all started... Thank you Art!




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

By Preston Lerner         February 2004
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-
 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.

Page 1 | Page 3 | Page 4