Based on readings from a torque sensor developed by AVL Racing, the US Army Top Fuel dragster recorded a peak 11,051 horsepower during a recent test in California.
That surpasses even the most optimistic of estimates that the drag racing industry has tossed around for the past quarter century. Since a Top Fuel nitro engine could never be accurately measured on a dyno, it was left up to mathematicians and crew chiefs to crunch the numbers. Patrick Hale, developer of engine simulation software programs, first calculated that Eddie Hill’s then record-setting run of 5.066 in 1988 required 4,000 horsepower. The number doubled to 8,000 following Doug Kalitta’s 4.486 at 333.91 mph at Houston in 2003.
Since then, of course, Top Fuel now runs 1,000 feet and have mandatory rev limiters. (For a full report on how these rev limiters or timing retard boxes work on a nitro engine, check out this EngineLabs story.) But that hasn’t stopped the horsepower race. Crew chiefs continued to pour more fuel into the engine and Hale later analyzed a 2012 run of 3.701 at 328.78 mph by Antron Brown at 10,100 horsepower when the car hit 5.1g some 2.5 seconds into the run.
Again, this was all done with mathematics. Now the Don Schumacher Top Fuel team is gathering empirical data using AVL’s new torque-sensing coupler that is mounted between the clutch pack and the rear differential. It reads changes in magnetic fields to generate a torque signal that is logged by the Racepak data acquisition system. The horsepower is then calculated based on the torque and rpm.
The British-based publication Race Engine Technology followed along with a video crew on the first test of the system at Maple Grove following the Keystone Nationals. At peak acceleration of between 5.5g and 6g, the data spiked at 10,156 horsepower. Crew Chief Mike Green observed that the average was “well over 7,000 horsepower.” The video notes near the end that a second test was conducted in California where the 11,051 reading was recorded.
A full report on the test will be published in the #90 issue of Race Engine Technology, and the magazine staff will conduct a seminar on the topic at this week’s PRI Show in Indianapolis. EngineLabs will be there, as well, so expect a followup report with more details from the show.