crackcase vent filters??

xsnapshot

^What? Don't spread miss-information. The ECU does NOT take into account "fuel vapor" as part of the fueling process. And how does "fuel vapor" come from oil? It doesn't. What happens if one engine has more blow by than others? How would the ECU account for that? It doesn't.....

The PCV valve is responsible for what it's name implies; Positive crank case ventilation and it's purely emissions related. It sucks up blowby gasses/oil and deposits them into the intake tract, where they are ingested/burned. This is much cleaner than venting to atmosphere.

The blowby/oil could be considered a performance detriment, as Its been shown to lower the effective octane of the mixture in cylinder. If you don't mind breaking a few laws, then vent the crank case to atmosphere and plug the intake ports. Just make sure your atmospheric vent is free flowing enough that pressure is not building up in the crank case from blowby. I will repeat that.....check your vents/filters regulary because you do NOT want pressure building up in your crankcase.

It could also be argued that leaving the PCV system in place will help minimize pumping losses, as it places the crankcase under a vacuum, which reduces resistance on the rotating assembly. This resistance however, is extremely minimal, and I doubt you'd notice any measurable reductions in mpg or horsepower because of it.