BIG corrections to Jim's MAF/AFM information

[mark kibort <mkibort@xxxxxxxxxxxxxx>]

With all due respect Jim.  =


The AFM DOES measure mass flow . Basic aerodynamics say that I sent air
over an air foil (which the flapper is a crude air foil)  it will move
according to mass flow over it .   Pressure diverential of the two sides =
of
the flapper valve make the flapper move. Lower pressure on the back of th=
e
flapper , higher pressure on the fron of it  makes it move  (its stablize=
d
by a 90 degree opposed flap that resists flutters as this would directly
effect fuel mixures) .  Air speed is fixed by the volumetric efficiency o=
f
the engine.   So , call your engine  100% efficient.   at  2.5 liters you=

would move 240CFM of air at 6000 rpm.

Now, stay with me here.  through a 6 squar inch hole, (that of a common
AFM),  lets just say you would be moving air at about 60 mph .  Now ,
remember basic areodynamics.  at altitude ,  the air is less dense.  So,
your engine is still taking 240 CFM , but it is 240CFM of less dense air.=
  =

Make sense.  so , if the speed is the same throught the engine, the flapp=
er
valve will be deflected less.  JUST PLAIN SENSE.  CIS systems move the sa=
me
way and are based on the same principals. (although the fuel metering is
constant with a fuel metering piston.)    Speed of air does nothing, its
differential pressure that does the work!!  You should know this! you see=
m
to know everything else.

YES , the ECU get data from temp sensors and pressure sensors  to fine tu=
ne
and  other parameters as you know.   (now this is your area of expertise,=
) =

 I imagine with a 120 degree day  your timing and fuel mixture would chan=
ge
to provide protection of pinging.   the same mass flow at a lower temp
would not have the tendancy to detonate.  correct??  =


Please , think before you reply back.  This is my area of expertise.  You=

are the LIST's god and have a responsibility to do your homework here.  =

JUST think for one minute.  Do you think that the flapper valve in a AFM
would move more or less at  the same speed of air through it at 2 differe=
nt
air densities   think , think............Yep , you guesed it ,  it would
move less for the less dense air! at  the same speed.   Now, do you think=

the speed increases to a engine ?   I think you really never thought this=

one through
If Im wrong, well, I will owe you a million "im sorry's"    That is why
airplanes go so fast at altitude   speed over the sensing devices are
saying 200mph, but your going 500mph ground speed.  The stall speed of a =
U2
is 70 mph, at 80,000 feet thats close to 500mph
Point being tha.t on an engine your speed is fixed to the displacement an=
d
the rpm.   so, air speed stays the same.   the pressure differential is
what does the work.   and it changes for alititude automatically.   =


as far as the MAF goes, yes this a very sensitve temp sensor that needs
constant measureing of temp , barametric pressure, and humidity (i imagin=
e)
 for the ecu to  calculate mass flow. =


Who ever told you about a flying surface , or AFM moving due to air speed=

REALLY needs to go back to school.

Help us out here with  an explanation of your last comments  below

mark Kibort
(www.electricsupecharger.com) =






 Message text written by Jim Conforti
>mark kibort writes: (and Shark corrects in his typical Politically
                     Incorrect style)

> Thanks for your response. Make no mistake , a AFM is a mass flow device=
.
> very accurate as

  BZZZZT.. wrong.. thank you for playing.. (next contestant) *grin*

  THE AFM measures VOLUME flow rates.. which must be corrected for =

  Pressure and Temperature to become "mass equivalent"

  It does NOT measure mass.. not at ALL.. whomever is telling you
  this needs to go back to school.<

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