Danny Thompson and Challenger II return to Bonneville one last time

The Challenger II at Bonneville in August 2016. Photo by Holly Martin, courtesy Thompson LSR.

Last month, Danny Thompson drove the Challenger II streamliner to an SCTA two-way average speed of 406.769 MPH, setting a new SCTA AA/FS record in the process. On September 15, Danny Thompson will return to Utah’s Bonneville Salt Flats for a final attempt at both a new FIA class record and a new piston-powered land speed record, before officially retiring the Challenger II at the end of Mike Cook’s Land Speed Shootout on September 20.

Mike Cook’s event will run under FIA (and for motorcyclists, FIM) sanctioning on an 11-mile course that gives competitors three more miles to work with compared to the track used by the SCTA during last month’s Speed Week. To help preserve salt surface conditions, the Land Speed Shootout event is open only to those capable of challenging an existing record, limiting the total number of cars and motorcycles participating. Danny Thompson expects to run against just four or five other streamliners, which should allow for several attempts at the records (assuming, of course, that the weather and the salt cooperate).

Under FIA rules, the two passes must be completed within a 60-minute window, a more complicated process than one would think. Assuming the first pass is record-worthy, Danny must get the car stopped and turned around before the crew sets to work. After removing Challenger II’s body panels, the team must add 50 gallons of fuel; change the oil and set the valves in both engines; swap out 32 spark plugs (two per cylinder); change four tires; repack (or replace) the parachutes; and remount the bodywork. Assuming weather conditions are favorable, it’s then up to Danny to deliver a second record-worthy pass.

As August’s second record-setting pass demonstrated, something can always go wrong. After running over 411 MPH on Saturday, August 13, a problem with a fuel distribution valve on the rear Hemi V-8 caused it to run rich on Sunday, dropping horsepower significantly and reducing the return pass speed to 402.348 MPH. That was still sufficient for a two-way SCTA record, but if Danny is to set new FIA class and piston-powered records, the margin of error narrows significantly.

In the FIA’s Category A, Group II, Class 11 (for normally aspirated two or four stroke reciprocating engines over 8,000cc, or 488cu.in.), the existing record of 414.316 MPH is held by Charles Nearburg and the Spirit of Rhett streamliner. Besting this will require two passes faster than Danny’s run at SCTA’s Speed Week last month, though the Challenger II has run as fast as 419 MPH (on a single pass) at Bonneville in the past.

As for the absolute piston powered record, that would require Danny and the team to top the 439.562 average set by George Poteet in the Speed Demon streamliner in September 2012. Unlike the Challenger II, the Speed Demon relies upon forced induction (turbocharging, to be exact) to produce 2,500 horsepower from just 368-cu.in., which puts it in the FIA’s Category A, Group I, Class 10. Though longer and heavier than the Speed Demon, the Challenger II produces 2,500 horsepower per engine, which, with the right conditions, the right gearing and just a bit of luck, may be enough to bring home a second FIA record.

The Thompson LSR team will be posting live updates from Mike Cook’s Land Speed Shootout to its Twitter, Facebook and Instagram accounts, beginning on Thursday, September 15. Regardless of what happens, Danny insists the event will be the last appearance for the Challenger II, and most likely for Danny himself. Win, lose, or draw, he can walk away knowing he did all he could to honor his father’s legacy at Bonneville.

See original article at" https://blog.hemmings.com/index.php/2016/09/12/danny-thompson-and-challenger-ii-return-to-bonneville-one-last-time/