[s-cars] MAF screen removal-please explain

[QSHIPQ at aol.com]

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[ Picked text/plain from multipart/alternative ]
That's not how I see it, it's "if your pumps ancillaries can measure it
correctly"....  More air doesn't necessarily translate to better engine
performance, you need to correctly measure it to make that claim.  Screen
affects laminar flow and pressure accross a venturi.  There's a ton more on
this in the archives.  IMS, my discussions with a bosch dude, he said leave
dem alone, or at the very least leave the incoming side in.

Mark, the mass that enters is the same, it's the measure of it that's
critical to the properties of laminar flow.  The key is what ever tumbles
(turbulence) or other orientation passes the venturi wing is key to the MAF
properly measuring that 100cfm.

All in the archives...  From my sidedraft days (currently on my road rocket),
I'm pretty convinced  from practical experience that anything you do in front
or behind a venturi, affects its measure of air.  In terms of a MAF, that
would also affect it's measure of air mass.  For a simple experiment, put
your house fan in front of the screen door, with a sail tape on the other
side, then open the door.

Yeeha, find that website MLP :)

HTH and my .02

SJ
85 FJ1387 with Mikunis and small sreens, new jets...

In a message dated 4/19/2003 8:02:53 AM Central Daylight Time,
strangconst at rogers.com writes:

Snip.
Now for part two, does removing the screen change the way in which the hot
wire actually measures the MASS of air (not flow or velocity) passing
through the meter?  I don't know.  I'm inclined to believe that it would,
but I'd defer to the more sage advice of the engineering types on the list.
/Snip.


By removing the screens, you are NOT changing the MASS of air flow that
enters the MAF for a given amount of air flow.
You are just making it easier to get in / out. If the motor is drawing 100
CFM, it will draw that thru the MAF, and will give the appropriate signal
from the MAF, regardless of screens.

As Hap pointed out, it's the 'Negative Boost'. By reducing any obstruction
to with in the inlet stream, you increase the pressure available to the
turbo, which equals more boost. Similarly by decreasing the pressure drop
across the filter you increase boost.
While decreasing pressure drops, you allow more flow. If you pump can accept
it.

At least that's the way I see it .

Mark S