After seeing an American Le Mans Series GT-class victory snatched away by a failure at the series' technical inspection shed, Flying Lizard Motorsports did a thorough investigation as to how they failed the post-race stall test. They found the problem and unlike most teams, put out a statement not only explaining what happened, but the entire process of the stall test. The statement follows.
"Hi everyone – we've received lots of questions on the Mosport results. As you know, we won the race, but the No. 45 did not pass post-race technical inspection and we did not receive any points for the race win towards the championship. Many of you have asked: What is an engine stall test? Why didn't you pass? What does that mean?
Here are some answers for you: After each qualifying session and race, IMSA (the regulating body of the American Le Mans... Series) executes a series of checks on the top finishing cars to ensure that all participants meet the specified technical guidelines for their class. The stall test is one of these.
The purpose of this test is to check that no more air can get to the engine than the rules allow. Controlling this is one of the ways the Series balances the performance of the cars. Performing this test is pretty simple. While the car is idling, the ...air intakes are physically blocked. Blocking the air intakes should eliminate all air into the engine, causing it to stall. If the engine does not stall, it means that some additional air is getting to the engine, and it is possible that extra air could create more power.
There are many ways that extra air could get to the engine: cracks in the manifold, leaks in various seals, etc. To our surprise, the No. 45 did not stall during this test after the race and was disqualified. You can imagine all the mechanics and engine people pulling their hair out trying to figure out what had gone wrong. We could not see anything wrong, and so protested the disqualification.
We investigated the issue more thoroughly when the car was returned to us, and found that the air cleaner had been improperly fitted. This caused the device to flex during the race and the seal to eventually fail. This is very likely what caused us to fail the stall test. While we are not certain that this caused us any advantage, rules are rules, and we support the Steward's ruling. A very disappointing end to a great race. Now on to Mid-Ohio!"
Source: Flying Lizards