vacuum hoses connected to fuel injectors?!?

[D_Eclipse9916]

Another point to the above pic...that would also not be a proper design because the air from the crankcase would be introduced to the engine, unmetered. It is on purpase that the PCV system takes air after the filter and sensor, but before the TB. Air diverted into the crankcase should nearly equal air coming out and into the manifold to ensure all the air going in the engine is accurately accounted for.

ECUs already account for this in their engineering (or should, even DSM ecus account for this "air". :thumbup: You are correct in the fact that between filter to TB there should not be "vacuum" in the sense of the meaning we are using it.

The breather line, (whats it is called between a hose after the MAF and into the engine) is used to feed fresh, filtered air into the engine at idle/light load conditions. This is because the PCV valve is using manifold vacuum to pull crankcase gases. However when you get into the throttle, boost closes the PCV and pushes out the breather hose into your intake, this is why you have crap in your intake as well.


Many foolish people (including me before I learned) simply pop off the breather to the air.

This effectively created two problems
1. It breaths in, therefore your getting non-filtered air into your crankcase.
2. The ECU has calculated for this, so even though it is a small amount, it is calculated for, effectively reducing the ability of your ECU to compensate for changes.

The proper way is to have it all hooked up, its not just for emissions, partly is though. The correct way would be to have 2 catch cans for both the breather hoses, and the PVC. However, you want pretty strong vacuum, so many racers have actually put vacuum pumps in to help get rid of crankcase pressure, making more power.