crackcase vent filters??

6SPD_FTW

I've never personally analyzed blow-by gases like the EPA has, so I don't know for a fact. I have read in several places that blow-by is mostly unburnt fuel - and the 70% figure is what was attached to those statements. The flame front extinguishes itself as it gets close to the relatively cool cylinder walls, aka, barrier layer. If that layer does get burnt, you overheat and melt pistons. Blow-by is mostly hydrocarbons because the piston rings (hopefully) never actually get exposed to the by-products of combustion until the exhaust stroke. The rings and cylinder walls are protected on the power stroke by that boundary layer of unburnt fuel and air...which is what would be blowing right by the rings. Blow-by shouldn't be exhaust by-products unless it's happening on the exhaust stroke. If exhaust gases are leaking passed rings on the power stroke, you got some real serious problems and probably a few pistons with holes burned through them.

The ECM has no way of monitoring PCV flow....I know this. As far as it being figured into the base fuel map, all I know is Toyota must be more advanced that Nissan or Mitsubishi or Subaru because Toyota ECM's DO factor PCV flow into fuel delivery (particularly at idle and light-load driving). Toyota ECM's have no way to monitor PCV or modify it, however it is still factored into the base fuel schedule. I assumed Nissan...and all other manufacturers....would do the same. I suppose Toyota is ahead of the curve on that one. Nissan's, I suppose, just threw it on there and use the AFR sensor and feedback control to compensate for it.

And how is there no such thing as an AFR sensor? I thought it was a pretty common thing on vehicles these days. I know for a fact my 370Z has two of 'em. It also has O2 sensors too - two of them as well. I know because I've logged them before on Autoenginuity. The AFR's read 2.2V in closed loop and the O2 sensors read anywhere from 0-1V, depending on load.

Just having a VTA setup on the PCV is fine short-term. But without circulating some fresh air through there, it is absolutely impossible that all the water vapor, fuel vapors and oil fumes are going to do anything other than sit in the crankcase and contaminate the oil. Whereas if you leave it alone and install a catch can to prevent oil from getting siphoned through the intake, you get the benefit of knowing your oil isn't getting turned to sludge. I'm leaving mine alone because I plan on my Z lasting well beyond 200,000 miles on the original engine. Each to their own, but I don't think it's a smart idea.