Boostedbus
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Going through this train wreck of a thread has been pretty excruciating. There is a lot of bad information here, and enough good to sort of make the read worth it. For some anyway. Couple of points:
- The PCV system has a "dirty" side and a "clean" side. The dirty side pulls the vapors out of the crankcase and introduces them into the intake tract to be burned. The clean side allows clean air to be pulled into the crankcase to provide some flow through the system. Putting a catch can on the clean side doesn't really get you anything. NONE of that has ANYTHING to do with DI, Turbos, or VVT. Although, the engineering and design work of the PCV systems on ANY boosted engine is more complicated than an NA engine.
- The 7.3L Godzilla engine is intended to replace the 6.8L V10 and the 6.2L V8's. There is no point in having TWO completely different engines for the F250 to F750 range. 6.2 was "OK" for the Super Duty 250-350, and marginal for the 450-550 trucks. Up until 2015, that was the top of the line. When Ford went back into the Medium truck market, the 6.8 went into the 650 and 750. Not cost effective. The 7.3 replaces BOTH. It was all about COST while getting economies of scale. This is ONLY about available GAS engines. NOT the 6.7 diesel.
- For the record, I have a JLT kit on my '16, and a Saleen separator on my '88 Stang with a 331 stroker. It doesn't have Di, Eco, or Boost!!! I'm going to put one on my wife's '19 Stang GT in the next couple weeks. It doesn't go out in winter!
The clean side is clean when the engine is producing vacuum but when it’s not there is positive pressure (in this case it would be called blow by) and that could still let oil into the engine intake air. My system abandons the clean side port which pulled from driver’s side turbo inlet duct and now pulls air straight from a new tap in the air filter box into a new supplied oil filler cap. That also allows you to use that turbo inlet tap for the secondary vacuum for under boost conditions. My clean side hose had oil in it when I pulled it for the install with only 8,000mi. I posted a pic of that hose.The clean side allows clean air to be pulled into the crankcase to provide some flow through the system. Putting a catch can on the clean side doesn't really get you anything.

So now the blow by in that hose (oil) can’t go back into and through the drivers side turbo and forced inducted into the engine via coming from the clean side. I hope this helps to put the train back up on the tracks.
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