It's there so that they don't fail emissions on the US06 (Highway) driving cycle. Keeping the engine on stoich during short duration, moderate accelerations goes a long way to reducing CO and HC numbers.Originally Posted by 5_Liter_Eater
Can you get more torque with some enrichment? Yes. Do they NEED more torque in the OEM application? Not really. The bottom line is: "If you don't meet emissions, you don't sell vehicles. Period."