The ignition timing is advanced back to the maximum value. To reduce power and the acceleration of the driveshaft and tires, the ignition advance is retarded from 56 degrees to 27-a strategy to keep the tires gripping the track surface instead of spinning. The motor screams at its 8300 rpm redline, and the tires buckle under the load of getting the 2300-pound dragster moving.
On March 13, 2010, in Gainesville, Fla., Kalitta driver David Grubnic set a top speed record on the 1000-foot track. They perform this harried rebuild in just 40 minutes. So the engine is rebuilt after every run by a team of eight mechanics. The extreme internal forces literally flatten the crankshaft bearings and destroy valve springs during a pass. The supercharger, which is just a belt-driven air pump that force-feeds the engine, is so massive that it takes 700 hp to run it. The basic layout is very similar to the 1964 Dodge Hemi 426 V8-16 pushrod-activated valves-but with two spark plugs for each cylinder and a total displacement of 500 cubic inches. Current estimates are in the 8000 neighborhood, and, no, we didn't mistakenly add a zero on the end. EngineĪ top-fueler's exact horsepower is a mystery-there isn't a dynamometer that can handle one. The resulting grip is akin to driving on flypaper. The special blend of tread rubber is designed to adhere to the adhesive that's applied to the track. With increasing vehicle speed, the tires expand to a final diameter of 44 inches. At the start, the 36-inch-diameter tires squat as the sidewalls wrap around the wheels' bead locks. The bias-ply tires also dramatically change diameter over a run, which has the effect of altering the overall gearing. Specially constructed Goodyears have the intimidating task of transferring all that rotational energy to forward speed. The discs get so hot that at least two of them are welded together by the run's end. If it engages too quickly, the tires will spin, but if it's too lazy, the car won't accelerate as fast as possible. The clutch is tuned according to track conditions. A hydraulically motivated throw-out bearing operates off a simple timer (computer controls are illegal). "The clutch is the lifeline of the car," Oberhofer says, because it regulates wheelspin by gradually engaging and slipping as the car moves down the track. ClutchĪ five-disc dry clutch is the only link between the engine and the locked rear end-there's no transmission. That kind of flow requires a firehose-like fuel line. The 58 nozzles in the intake tract are always open, dumping about 5 gallons of fuel in a 4-second run. But nitro is an oxygen-rich compound that requires less air to burn, so the engine can consume more of it, thereby producing greater power. Interestingly, a gallon of nitromethane, which costs $58, has less energy content than gasoline (14 kilowatt-hours versus 34).
Southern California residents will particularly enjoy the footage from the late, lamented Orange County International Raceway which opened in 1967 and is shiny new in this video, choc full of entertaining moments.Top-fuelers burn a mixture that's 90 percent nitromethane and 10 percent alcohol. OK, cheesy, but the wonderful, grainy footage will pull you in even if you’re not a big fan of vintage drag racing. The 26 min film “Performance - On The Line” produced by Ford Public Relations’ Film and Electronic Communications Department, opens with these classic lines: “If performance is your game, if a drag is your bag, if you love horsepower smokin’ speed in a safe controlled atmosphere, then you’ve come to the right place.”
The Rabbit Hole Garage YouTube channel bills itself as “a channel for all my automotive related shenanigans,” and we’re grateful to its proprietor for uncovering and posting this 1960s-vintage promotional video celebrating the fast-growing sport of drag racing - “Drag racing in its 1960s/1970s heyday, featuring top drivers Gas Ronda, Ed Terry, Dick Loehr and more” although not all are properly identified.