[jimclark]

Originally Posted by Pandamasque

But that happens to get around the fuel economy/emissions tests that have VERY little to do with real life driving on the road. You can get fantastic official economy and emissions rating by coasting around with that tiny turbo engine, as long as the turbo doesn't kick in. But drive it hard, you may be better off with a big lazy pushrod V8. This whole downsizing trend only makes sense for cars that are driven at 1/10 most of the time. Even some actual road car engineers admit it to road car journos, it's all to get good official numbers (at the expense of weight, complexity and thus potential reliability problems).

How is that relevant to racing?

Exackly...