Originally posted by Steve Bassen:
Check out the dyno's on a stock Duratec. The engine runs out of breath right around 3100 when it's just breathing through the primary runners/valves, causing a dip in power until the secondaries open up. Ideally you'd want the secondaries to open up a few hundred rpms sooner than stock.....
i don't have my plots in front of me... but iirc the dip occured at ~3400 rpm just when the secondariers were opening... i took the loss as something to do with air velocity and the maybe something to do with the pcm.
