There’s a lot of performance to gain when you’re allowed to run an engine dirtier so they run them clean during the tests. Then when they get out in the real wo

There’s a lot of performance to gain when you’re allowed to run an engine dirtier so they run them clean during the tests. Then when they get out in the real world, they run them at “higher performance” levels that might mean better fuel economy, that might be more horsepower, that might be a smoother, running engine or it could be more durability.