Quote:
Originally Posted by mwebb
right
more information
here goes
blue trace is crankcase pressure at idle on the VW ALH TDi engine
every one of those pressure pulse s that is not captured by the
Crankcase vent valve or PCv system would be expelled to atmosphere through the catch can plumbing -
this would be the source of the HC pollution i was referring to
the pressure pulses are much stronger off idle at cruise or WOT .
there is no way around this when using the catch can , you will be venting / wasting HC emissions that could be burned and would provide some slight amount of power while reducing HC emissions
there is no benefit to using a catch can and the system pollutes more
blue trace
i hope this makes it easier to understand , with understanding comes
responsibility
- now you can not say -
" i do not see how this is bad "
you can not put the genie back into the bottle
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Maybe I missed something in someone else's post, but my catch can was installed in the hose between the PCV and intake manifold, just below the carby.
The whole thing was under manifold vacuum, there was no "venting", there was nothing "expelled to atmosphere", it simply separated the heavier stuff from the lighter stuff before it reached the manifold. I then drained this heavier stuff off, when the engine was stopped.
The only down side I can see is that I may have been removing a bit of lubrication for the valve stems.