Kingtal0n

what teh f

The factory produced 100,000's (or whatever) of these cars (Sr20de/sr20det) all the same with crankcase that rely on the post air filter duct for their pressure drops (the post air filter tube feeds the crankcase during vacuum and visca versa at wot)



hundreds of thousands of them like that.

They did this because it was shown in the computer modelling that without such a pressure drop, any engine would become a leaking smoking dripping pile of shit in so few miles


And now you want to remove it because somebody on the internet says its 'dirty air' lol - I Don't blame you. It does sound like dirty air and the whole appearance of emissions can seem misleading in this case. But lets clear it up

clear sentence: the dirty air inside the crankcase is below the pistons (with the engine oil and oil system) whereas it NEEDS to be above the pistons (where it can't harm the engine oil) and by removing or deleting that tube(any pcv tubes) you allow it to propagate and persist inside the crankcase with the oil system where it does the most damage.

In other words, the 'dirty air' that gets below the piston was accidentally released there, that is called 'blow by'. If we could, we would use a 100% perfect seal piston ring to avoid that from happening. But we can't.
Where that air(its really a mixture of hydrocarbon fragments suspended in fluid) should have stayed, is inside the combustion chamber, but it leaked out, see? So we need to put it back into the combustion chamber somehow, and fast. Either that or find another way to suction it out somehow (vacuum pump).
[size=3]But under absolutely no circumstances should you ever simply open a vent to the atmosphere from the crankcase and allow the pressure to build and force its own way out over time 'delete pcv' That gives the filthy air time to circulate and literally bounce from every conceivable surface, as gas molecules are want to do at very high rate.
Especially hot, energetic, fragments of carbon compounds displaying reactive radical species of all manner shape and size!

By deleting PCV, you prevent the engine from moving that dirty air back into the combustion chamber. So where does it go instead? It contaminates the engine oil, sticks to engine parts, lowers the life expectancy of the engine. It isn't air; its full of partially combusted hydrocarbon fragments which form that black tar, sticky gooey substance, and diamond-like crust on engine parts. By the way, have you seen the size of the orifice that feeds an sr20 cam oil squirter?


Oh and the unmetered air argument, I love that. Did you know, everytime you step on a brake pedal you feed an engine unmetered air? Unmetered air is only a concern when the mass is high enough to throw the air fuel ratio off far enough during a troubling time, i.e. when the engine pressure in the intake manifold is higher than 50KPA and we are talking greater than say 2lb/min worth of airflow that is 'slipping by'. The trifle amount that should be leaving a fully sealed crankcase with healthy piston ring/wall character under acceptable operating conditions is negligible, probably closer to 0.2lb/min (about 1% of the flow required to trigger a 'unmetered air' issue) or less.