|
OEMs usually play the emissions game rather seriously. Like VERY SERIOUSLY. For example look at this stock map. They went from 50% PFI to 100% DI at 2400rpm because that is where Scavenging peaks in this engine. So that is where going PFI will make the fuel short circuit engine and go directly to exhaust causing HC emissions. So by going DI it allows them to scavenge harder. Upto 1-2% O2 in the exhaust is manageable by the CAT. Anything over that the CAT cannot keep up.
|