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Funny Cars

     Nothing Funny About Them

Funny Car is one of those names that stopped making sense about five minutes after the class became serious.

From the grandstands, a modern Funny Car still carries enough production-car shape to look familiar. There is a nose, a roof, headlights painted where headlights ought to be, and enough Mustang, Camaro or whatever-the-factory-is-promoting-this-year in the outline to keep the marketing department interested.

Then the entire body flips up and ruins the illusion. Underneath is a 125-inch chromoly tube chassis, a driver sitting in the middle behind an 11,000-horsepower nitro Hemi, a timer-controlled multi-disc clutch, enormous rear slicks and very little that has ever seen the inside of an assembly plant.

The whole package weighs roughly 2,600 pounds, covers 1,000 feet in the 3.8-second range and can exceed 330 mph. That gives it more than four horsepower for every pound it weighs, wrapped in a short-wheelbase body that still insists on looking vaguely civilized.

Funny? Only if your sense of humor includes fire.

Why Do They Call It a Funny Car?

In the early 1960s, Factory Experimental racers began moving engines rearward and axles forward to improve weight transfer. Wheelbases changed, bodies got lighter, and production-car proportions started looking wrong.

They looked funny. Altered-wheelbase cars and lightweight flip-top bodies pushed the idea rapidly toward the purpose-built machines that followed, and the name stayed even after almost everything that originally looked odd disappeared.

Today’s Funny Car no longer gets its strange appearance from axles sitting in peculiar places. The approved body shape looks almost normal from a distance, right up until the shell rises and exposes the race car underneath.

Then the joke explains itself.

The Body — Stock in the Same Way a Halloween Mask Is a Face

A current Funny Car body is a carbon-fiber replica loosely based on an approved production coupe or sedan. The key word there is replica. The headlights, grille and most of the other street-car details are graphics, and there are no working doors waiting for somebody to climb through.

The entire shell lifts from the front to expose the chassis, engine and driver. With the body down, the car can still suggest Mustang or Camaro. Raise it and the family resemblance ends in a hurry.

The shell is not merely camouflage. At more than 300 mph it is a serious aerodynamic device. The rear spoiler can produce around 6,000 pounds of downforce on a car weighing roughly 2,600 pounds, so the air can push more than twice the car’s static weight onto the rear tires.

That spoiler is not there because somebody had a little carbon fiber left over. The body has to keep the rear end planted, remain stable at more than 330 mph and keep the front end interested in pavement rather than sky.

The Engine — Five Hundred Inches With Very Bad Intentions

At the center of the operation is a purpose-built aluminum Hemi-style V-8 limited to 500 cubic inches, or about 8.2 liters. It uses a 14-71 Roots-type supercharger, mechanical fuel injection and a fuel mixture containing as much as 90 percent nitromethane.

The result is more than 11,000 horsepower from an engine turning roughly 7,700 rpm. That rpm number surprises people accustomed to associating extreme power with extreme engine speed. Funny Car does not need 12,000 or 15,000 rpm. Five hundred cubic inches, a giant blower and enough nitro to make ordinary gasoline look shy take care of the rest.

The basic four-stroke layout would still be recognizable to anybody who understands a V-8. The scale would not. Cylinder pressure, heat and fuel volume are operating in a neighborhood where ordinary performance hardware would quickly become scrap.

There is no attempt to make the engine polite or long-lived by street-car standards. Its job is wonderfully narrow: make outrageous power immediately, complete the burnout and 1,000-foot run, and survive long enough to hand the car back to the crew.

The Blower and Fuel System — Moving Air and Nitro by the Bucket

The 14-71 blower is mechanically driven from the engine and can move air in the neighborhood of 3,500 cubic feet per minute. For anybody who remembers when an 850-cfm Holley meant there was something serious under the hood, that number should establish the scale.

Mechanical injection feeds nitromethane through multiple nozzles, and the fuel system can move well over 100 gallons per minute at maximum demand. A typical Funny Car can use roughly 15 gallons through the burnout, staging and one full pass.

Fuel economy left the conversation several thousand horsepower ago. Nitromethane carries oxygen within the fuel itself, allowing the engine to burn far more fuel in each cycle than a gasoline engine depending only on oxygen entering with the air. The blower forces still more air into the cylinders, producing the cylinder pressure needed to make the scoreboard believable.

The injector hat and blower are visual signatures, but their real job is simply moving enormous quantities of air and fuel for less than four seconds of useful work.

The Chassis — One Hundred Twenty-Five Inches Changes Everything

The chromoly tube chassis has to hold the engine, driver, clutch, rear axle and suspension in a package limited to roughly 125 inches of wheelbase. That short wheelbase is one of the biggest reasons Funny Car has its own personality.

For scale, a Top Fuel dragster stretches roughly 280 to 300 inches between the axles. Funny Car puts nearly the same level of nitro power into less than half that distance. That comparison is useful because it explains what the driver feels: the shorter car reacts more quickly to steering input, tire shake, traction changes and anything else trying to send it somewhere unintended.

The chassis also has to live under a large aerodynamic shell, so straight-line stability depends on chassis behavior and aerodynamics agreeing at very high speed. This is not a dragster wearing a body; it is a purpose-built Funny Car chassis built around its own wheelbase, driver position and aerodynamic package.

The Driver Gets the Best Seat in a Bad Neighborhood

The Funny Car puts the engine in front of the driver. The driver sits in the middle of the chassis inside a protective cage, surrounded by belts, fire protection, padding and enough structure to make the word cockpit more appropriate than seat.

That front-engine arrangement is partly an inheritance from the class’s production-car roots. The engine stayed ahead of the driver even as the body, chassis and horsepower moved farther and farther away from anything Detroit intended for the street.

There is an obvious disadvantage to sitting behind an 11,000-horsepower nitro engine: when the engine decides to have a bad afternoon, the driver has an excellent view. Header flames run beside the body. Blower explosions can damage or remove body panels. Oil, fuel, fire and expensive pieces of machinery are all happening a few feet in front of the windshield.

The enclosed body limits visibility while the shorter wheelbase makes the car responsive to small disturbances. The driver therefore gets plenty to do even though the race is over before most people could finish describing the problem. There are quieter places to sit. They do not come with a 3.8-second time slip.

The Clutch — Teaching 11,000 Horsepower Some Manners

A modern nitro Funny Car does not use a conventional multi-speed transmission. The engine sends power through a sophisticated multi-disc clutch to the rear end, with timers controlling how aggressively the clutch locks up during the run.

The crew chief’s problem is simple to describe and difficult to solve: give the rear tires every bit of power the racetrack will accept, but not one bit more.

Too little clutch and the car is lazy. Too much and the tires spin. If the combination falls into tire shake, the chassis can hammer hard enough to make the driver wonder whether every tooth is still where it started.

The clutch is the power-management system. The engine already has more power than the tires can use at the starting line, so the tune-up determines how quickly that power reaches them as the car gains speed and aerodynamic load. The challenge is rarely finding power. It is teaching 11,000 horsepower manners for 1,000 feet.

The Rear Tires — Six Pounds of Air Versus 11,000 Horsepower

The rear slicks are about 18 inches wide, nearly 10 feet around and commonly run with roughly six pounds of air pressure. That does not sound like much pressure until the tire is asked to help manage thousands of pounds of downforce and more horsepower than a respectable collection of street cars.

At launch, the sidewalls wrinkle dramatically as the tire plants itself into the prepared surface. As speed increases, centrifugal force makes the tire grow taller, effectively changing the final-drive ratio while the car is moving.

The slick is therefore doing several jobs at once: providing traction, absorbing some of the launch, changing the effective gearing and trying to remain one piece at more than 330 mph.

Tire pressure, clutch application, track temperature and surface preparation all have to agree. The engine may attract the crowd, but the rear tires decide how much of that show reaches the finish line. Six psi still sounds ridiculous after you understand it.

The Burnout Is Not Just for the Crowd

Funny Cars do one of the best burnouts in racing, which is convenient because the crowd likes them and the rear tires need them.

The burnout heats the slicks and lays fresh rubber onto the racing surface. The driver rolls through the water, lights the tires and carries the burnout well past the starting line before stopping.

Then the car backs up. Crew members guide the driver into the tracks left by the burnout so the hot slicks return to the best-prepared pavement. It is one of the odd rituals newcomers notice immediately.

The smoke is entertaining. The point is traction. Funny Car has enough horsepower to turn the rear tires into white smoke almost anywhere on the track, so the entire launch procedure is an organized attempt to convince them not to.

Driving One — Four Seconds Is Plenty of Time for Trouble

From the outside, a Funny Car has a roof, windshield and body surrounding the driver, so it can look more civilized than it really is. Do not be fooled by the roof.

The driver has to complete the burnout, back into the groove, stage accurately, react to the Tree and keep a short-wheelbase car centered while the clutch comes in, the slicks change shape and aerodynamic load climbs rapidly.

A strong modern Funny Car can already be around 280 mph at the eighth-mile mark and still add another 50 mph or more before the finish. At 330 mph the car is traveling about 484 feet every second, so the last part of the run disappears in a hurry.

The driver also has to recognize when the run is no longer worth saving. Tire smoke, severe shake, a dropped cylinder or a car moving out of the groove can turn a competitive pass into a very expensive problem. Small steering corrections need to remain small; there is not enough time or pavement for a committee meeting once the car develops other plans.

Stopping One — Two Chutes and All Four Wheels

Crossing the finish line at more than 330 mph solves only the first half of the problem. The car still has to give all of that speed back before the shutdown area runs out.

Funny Cars deploy two parachutes for the serious high-speed work. Those chutes can generate several Gs of deceleration, while carbon-fiber disc brakes help finish the job as the speed comes down.

Funny Cars also use front brakes in addition to the rear braking system. That gives the driver four-wheel braking once the parachutes have knocked the big number off the speedometer, useful on a roughly 2,600-pound car with a short wheelbase and a full body.

The shutdown is part of the run, not an afterthought. Chutes have to deploy cleanly, the car has to remain stable during heavy deceleration and the driver still has to make the turnoff. The dramatic part is supposed to end at the finish line; anything after that is generally paperwork.

Body Up — Now You Can See What You Bought a Ticket For

Walk through a Funny Car pit and sooner or later the body will be raised. That is when the class makes the most sense.

The production-car illusion disappears and you can see the chromoly chassis, blower, fuel system, clutch area, rear axle, steering, fire bottles, driver’s cage and miles of plumbing packed beneath that carbon shell.

Between rounds, crews tear into the nitro machinery. Cylinder heads come off. Pistons and rods get inspected or replaced. The clutch comes apart. Data from the previous pass gets studied, and the combination is prepared to do another four seconds of work.

Components are not being asked whether they can survive another season or another oil change. They are being asked whether they are ready for another full-power pass. Four seconds of racing can mean most of the afternoon fixing whatever those four seconds tried to destroy.

Reading a Funny Car Run

Once you know what the car is trying to do, a pass becomes easier to read. Start with the rear tires. A clean launch wrinkles the sidewalls and moves the car forward without turning the starting line into a smoke machine. Violent shake means the tire, clutch and racetrack are arguing about how much power can be used.

Then watch the body and the centerline. A Funny Car that moves around early may require small steering corrections while the driver is still carrying tremendous acceleration. Farther down the track, even a small wiggle deserves attention because speed and aerodynamic load are climbing quickly.

Listen to the engine as well. A dropped cylinder changes the sound and can alter the way the car pulls because 11,000 horsepower is less cooperative when it stops arriving evenly. Tire smoke or a sudden change in engine note can tell you why the driver lifted before the scoreboard does.

Finally, watch the shutdown. Two clean parachutes, a straight deceleration and an uneventful turnoff are not the boring part of the run. They are evidence that everybody finished the job.

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