AFM vs. MAF

[mamarand@xxxxxxxxxxxxxxxxxxxxxxxxxx (mamarand)]

  Regarding the posting about the MAF on 944 turbos:
   
  <The Porsche modification guys like to claim a MAF conversion will
  give up to 30 extra HP ,but this is NOT the case.  What it will do is give
  improved throttle response therefore helping the car to get going, and will
  make the car "feel" faster.  The MAF may add some HP at part throttle
  because the intake air isn't being forced past the AF meters trap door ,but
  at full throttle when the AF meters door is fully open it will allow enough
  air for FULL HP in most cars.  *If* the AF meter on the E30 325i/M3's  flow
  as much as the one on a 944 turbo you will have enough air to make AT LEAST
  350HP!>
  
  The difference in flow between an air flow meter and MAF sensor is huge.  On a 
  flow bench it is like comparing apples and oranges.  The pressure drop at a 
  given CFM is easily a factor of ten different.  On normally aspirated cars 
  this relates to the amount of air that can be drawn into the cylinder.  On 
  turbos it relates to how quickly the turbo can spool up and how efficient the 
  turbo is.
  
  Not only does the MAF sensor allow the turbo to spool up and make power much 
  more quickly, it is far less susceptible to reversion pulses and pressure 
  surges in high boost pressure turbo applications.  The MAF conversion will 
  give a sizable boost in torque at low RPMs which will decrease acceleration 
  times dramatically.
  
  Mark Amarandos
  '88 M5   
  

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