STEALING THE 500: The Story of Carroll Shelby’s 1968 Turbine-Powered Indycars, Part 2 of 2

September 7, 2016
Stephen Cox Blog Presented by McGunegill Engine Performance
 
 
(Read Part 1 by clicking here) Ken Wallis was running out of time. Both of Carrol Shelby's turbine-powered cars were now at Indianapolis but they were nowhere near race-ready condition. His drivers, McLaren and Hulme, had only a six-day window before they returned to Europe for the Spanish Grand Prix.
 
In a desperate bid to make the cars competitive, Wallis used a liberal interpretation of USAC's rules to design a new annulus (the engine opening that fed air to the turbine). When measured by technical inspectors, the annulus was under the legal 16-inch limit. But at full throttle on the race track, a variable valve system opened to permit greater air flow into the turbine. At best, this was a careful translation of the rules. If they were caught there was no guarantee that USAC wouldn't immediately disqualify the Shelby/Wallis Turbines. Such a move would be an unmitigated disaster not only for the team principals, but also for Goodyear, their drivers and their sponsors.