MAFs

[Bruce Plecan]

> I'm trying to see the difference in intake air
> behavior between a turbo and NA car.  The speed of the
> air can cause turbulence but this should be the same
> regardless of the aspiration.

N/A can exist with nothing more then a butterfly right by the intake valve,
and in that case a IR is the best possible.  It has the whole atmosphere
filling the cylinder.  A turbo forces some ducting.

  One must choose an
> appropriatly sized pipe for the flow of the system.  I
> suppose that the compressor could do something to
> swirl(?) the incoming (and certainly the outgoing) air
> but if we're talking about a significant distance
> between the MAF and compressor then it shouldn't
> matter, should it?

Ya, but that kills throttle response,  1 inch on my 4' long tract makes a
noticeable difference..

> How does the IC affect the desirability of using blow
> through vs pull-through?

The air has to line up to go thru it, takes most of the votexing out of the
air.   This allows the air to be presented to the MAF the same way all the
time.  Which is critical.  If you can't get repeatable measurements on air
flow, then at best everything is erratic.

The IC's effect on the air
> mass should be measured either way, no? I've
> considered going blow through but decided that the
> life of the MAF would be reduced due to the oil in the
> system.  I spoke with Corky Bell about this and he
> found that his blow through MAFs only last around 10k
> miles before the oil kills them.

Is he using one that is best for the application?.   If a film type MAF I
readily understand that.   Where is does he use a PCV system?.   How well
set up is the oil fume air seperator?.   That is darn near always over
looked.  Mine is down stream of the MAF.    Not a problem.  Then I also use
a  check valve in series with the PCV valve so  that if it doesn't seat
perfectly, I don't pressureize the crankcase.
Bruce

  If you can
> effectively prevent the PCV from introducing the oil
> mist into the intake then it should help with the MAF
> life.
>
> Regards,
> Matt
>
>
> --- Bruce Plecan <nacelp at bright.net> wrote:
> >
> >
> > OK. what makes you think that?.
> > Maybe if the air column was inertia free,
> > First thought of mine is well look at a bath tub
> > drain.   Vortecs big time,
> > just to get the water thru.  Air acts just like
> > water, only far less dense.
> >   Specifically they were blow thrus,  but if that
> > bad blow thru, I can image
> > problems either way.
> > I've been going thru this in some detail,  luckily
> > my car has an Intercooler
> > so by locating the MAF between that and the TB just
> > makes sense, least to
> > me, and so far things are acting totally as
> > expected.
> > Bruce
> >
>
>
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