[Diy_efi] Speed-density vs. MAF/MAP...

[Marcell Gal]

Hi,

Perry wrote:
> Basically 100Kpa = 100% VE.  

????? *

> If you run an
> engine at WOT and record the MAP values for a given
> RPM, you'll get the VE curve of the motor.  You can

you mean that the RPM * VE(RPM) will be proportional to
(104kPa - MAP(RPM)) ? 
This makes sense (although I do not know how accurate this will be, you
need good resolution, exact ambient pressure, low noise etc...)
because pressure drop accross air filter and other 
things depends on airflow (and airflow is proportional to VE * RPM,
basicly engine power).
 But you still need to guess a multiplicative constant, right? 
(eg. guess your max VE?)

Does anyone have oversampled MAP logs (weather synchronized
to cam or not) to play with ?

thanx:
  Marcell

* your 1st statement kinda suggests that  MAP is proportional to VE,
 but that contradicts the very basics
of speed-density: we need VE(RPM, MAP) tables exactly because
there's not direct MAP ~ VE multiplicative relationship, primary because of 
the valves.

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