Borg-Warner makes the turbos for all three IndyCar engine suppliers, Chevrolet, Honda and Lotus, but the engine makers provide two compressor shrouds of their own design for homolgation by the series. Honda's singe-turbo engine is down on power compared to Chevrolet's and Lotus' twin-turbo motors, and Chevrolet has won all every race so far and taken all pole positions this season. Honda had a new shroud ready for the Long Beach GP and IndyCar allowed the change, but Chevy protested so Honda wasn't permitted to make the switch.

A three-man panel was selected to hear Chevy's appeal, and their verdict in favor of Honda means that the Japanese automaker was permitted to swap the shroud before this weekend's São Paulo race. The new shroud is said to be worth 10 to 15 more horsepower, but in the end, Chevrolet-powered racers managed to finish in seven of the top 10 positions.

Chevy had been contesting the ability to make an engine change at this point in the season, when there are no constant-parity clauses in the regulations and IndyCar has an agreed date in mid-June for such alterations to create parity. Honda's argument was that an agreement in 2010 that was meant to prevent turbo wars does allow the change it sought to make. The panel supported Honda's interpretation of the parity argument.

Chevy has said it will not appeal the decision. Now it's up to the Honda-powered drivers fitted with the new 0.74 A/R compressor cover to show they can do better than second place.

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    • 1 Second Ago
      • 3 Years Ago
      Hey AB, let's hire a better editor, eh? "...Chevrolet has won all every race so far..." Or at least clean it up when readers point it out. You're better than that!
      • 3 Years Ago
      Wow...problems like this already? It reminds me of 2001 at the Detroit Grand Prix when Ford and Honda were pissed over Toyota's cheating the pop-off valve rules in CART and teams sat out one of the practices.
      • 3 Years Ago
      Honda is afraid of Turbo wars.. They have had it too good in Indy, I am glad Chevrolet and Lotus came back to wake em up from their slumber
      • 3 Years Ago
      The Honda and Chev performance seemed as closely matched as could be in Brazil. If I was betting, on an oval the Honda would get my money and i fully expect both Ganassi cars will be on pole. Just the nature of single vs. double turbos now that Honda got their way PRIOR to any ovals being run! Lotus on the other hand is in real trouble, and furthermore, the stall out problem hasn't been fixed either.
      • 3 Years Ago
      I would not have called it a compressor shroud. Changing a compressor A/R ratio involves changing a compressor housing, or volute. A shroud would imply a cover to the compressor itself. Still, whatever IndyCar calls it is fine. More to the point, I suspect Honda has done more than simply change the A/R ratio......the article doesn't say the .74 A/R ratio is higher than before (although I suspect it is for more air flow)...A/R ratio is just the tip of the iceberg for volute changes.