Yes a single can w/pcv delete is blocking/deleting everything stock bar the rearward heads balance ports and CCV, and running the 3 sources to a single can with vent to inlet or (
) air (or exhaust)
Very interesting. I've given it some thought. Ramblings follow.
To comment on the obvious, with no PCV you miss out on the strongest source of vacuum (manifold vacuum) and have to make do with mere "ported vacuum" ahead of the turbo inducer. Commonly-accepted wisdom is that the PCV setup on a road car is for emissions reasons.
Emissions aside, low pressure and/or a mild vacuum in the crank case is a good thing to:
(a) reduce oil leaks;
(b) increase piston ring seal;
(c) reduce internal wind resistance for the crank & rods;
(d) reduce oil mist in the crank case and reduce the oil clinging to the trailing side of the crank & rods.
Many of the performance advantages above (and any serious % horsepower improvement) only occur when a scavenge pump (with a dry sump system OR just to pull gas out of a wet sump crank) are drawing a strong vacuum on the crank case at all different rev points.
[Summarised from "Four Stroke Performance Tuning" 4th Edition by A. Graham Bell, pages 545-547]
On a road car (under manifold vacuum conditions a lot of the time) I submit that benefits (a) to (d) above will still be present, but won't help on-boost performance.
"Vent to atmosphere" seems to be ok for competition engines, but not as good as a strong source of vacuum at all rev points via scavenge pump. I would think that the more limited vacuum draw of the pre-turbo pipe would still give some benefit (compared to vent-to-atmosphere) under boost conditions. An experience racer/tuner might be able to tell us if the crank vacuum benefits offset the detriment of a closed-loop system for a high performance application.
From the same book on page 551:
"
Any wet sump competition engine should have at least a 1" hose connected into each rocker cover and another 1" hose connected into the block"
There is no mention in the book of blocking the crank vent and relying on rocker cover breathers only. Just to speculate, it could work fine or perhaps sub-optimally under some conditions. On a performance engine it seems to me to be a retrograde step to reduce the gas flow (in exit points and total exit-hose cross sectional area) out of the engine. I also wonder if the factory balance of pressure and oil drainage is negatively affected by blocking the crank gas exit path.
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I've heard of crank case vacuum being generated via exhaust, although not for cars with a turbo or any form of muffler. Seems to be a naturally aspirated race-engine-only style of setup.