The Supercharger Early Top Fuel engines all used the classic 6-71 GMC supercharger that has grown into the current 14-71. NHRA rules now limit virtually all aspects of the fuel superchargers, including the inlet and outlet dimensions. But that hasn't stopped racers from improving the breed. The latest iteration is the Gibson/Miller supercharger designed by aerodynamicist Tim Gibson and built by Bill Miller Engineering (BME). At 50 percent overdrive, Miller says the blower easily pushes 60 psi of boost pressure (that's four atmospheres), and at 12,450 rpm rotor speed, the Gibson/Miller supercharger is capable of 3,750 cfm. According to Miller, that's an air speed of "about 250" mph exiting the supercharger. Pushing this much air, you would think the blower would be plenty hot at the end of a 3-second pass, but with the 12 gallons per minute of fuel sprayed through just the hat nozzles, Miller says the blower is barely warm to the touch if you were to snuggle up next to it on the return lane. That's because the nitro works to pull the heat out of the air despite the immense power required to drive the blower. Miller estimates it takes between 900 and 1,000 crankshaft horsepower to drive one of his superchargers. Just let that last fact settle in for a moment. One of the keys to the Gibson/Miller supercharger is end caps with gears on both ends of the blower. The two additional rear-mounted gears help stabilize the rotors, preventing distortion, which allows closer tolerances and improves efficiency. The entire blower weighs 86 pounds. One of the keys to the Gibson/Miller supercharger is end caps with gears on both ends of t Dale Armstrong built the original Top Fuel dyno that, with several changes, now resides at Bill Miller Engineering (BME) in Carson City, Nevada. The absorber was originally designed for testing huge radial aircraft engines during WWII. The dyno uses a 4:1 step-down gearbox to reduce these 8,000-rpm engines to a maximum 2,000 rpm input into the absorber. BME now uses alcohol engines on the dyno to help develop new components for the Top Fuel Gibson/Miller supercharger. Dale Armstrong built the original Top Fuel dyno that, with several changes, now resides at NHRA rules even limit the amount of twist, or helix angle, that can be designed into a Top Fuel supercharger. High-helix angle rotors are more efficient (as used on the Eaton TVS2300 supercharger on the '10 LS9 Corvette), but even this more efficient design is not legal in Top Fuel. NHRA rules even limit the amount of twist, or helix angle, that can be designed into a Top Five Top Fuel Facts You Probably Didn't Know • The noise from a blown nitro engine is due in part to the fact that you're hearing the tail end of the combustion process. • A Top Fuel engine will consume more than 14 gallons of fuel over the entire time from start-up to the finish line. • At peak power, each 62ci cylinder generates 1,000-plus horsepower, equaling 16 hp/ci. • All 12 quarts of engine oil are changed after warming the engine due to fuel dilution that turns the oil a sickly mustard color. • A Top Fuel driver would rate a Space Shuttle launch rather mild since he experiences in excess of 5 g's positive acceleration, while the Shuttle pulls a mere 3 g's. « | 1 | 2 | 3 | » | View Full Article By Jeff Smith Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!