Air filter/intake system alterations

[A B Able Truck]

Food for thought - I'm plagiazing;
While the Valvetronics control intake air and the throttle body remains in the full open position, you still need a certain amount of vacuum within the intake for proper CCV (diaphragm) operation. It is my belief that the measured restriction of the air filters help accomplish this task. If you change to an aftermarket (open air) filter such as K&N (when it's clean), it could throw this balance off. This could result in the diaphragms not closing correctly allowing more crackcase mist (oil) to enter the intake. While I'm plagiarizing - If excessive oil mist/vapor is present in the air intake the effect is to dramatically increase the potential for engine knock by lowering the effective octane level of the air/fuel mixture. If the Knock sensor detects any engine detonation "pinging" then it will retard your ignition timing to prevent further detonation. Oil is not as volatile as petrol and the effect is the explosion that pushes the engines piston down is not as violent which again equals less power. We also think the oil mist increases the Exhaust Gas Temperature (EGT).

http://www.nicoclub.com/archives/kn-vs-oem-filter.html