MAP Questions...

[Jim Staff]

> Jim, have you considered a simple speed throttle system using throttle 
> position
> and rpm to index a map? 
> 
> Throttle density systems are common on individual throttle body intakes
> especially for ported rotaries and agressive cam piston engines.
> 
> I have seen many successful (usually racing) applications where MAP of MAF
> sensors are useless.  You could adjust for ambient air pressure if you 
> prefer.

  Robert,
     The problem I have requires that it operate over very wide range of 
temperatures and altitudes. A TPS system would be very simple and I could do it 
with the scrap parts on my desk but it wouldn't be the best I could make it. 
Also I would have to have a butload of calibration curves for it based on the 
temp and altitude. I can check the temp no problem, I've got a small integrated 
0¡C to 100¡C National Semiconductor temp sensor. But I need some type of 
correction for the pressure. 
     This is what I know. The MAP sensor will give me a reading on the manifold 
vacume. I can correct this with a temp sensor to give the amount of air that the
engine desires. I was wondering how I would go about using this sensor to 
determine how much air I need. 
     Is a MAP system just mapped out? Like an array. Where temp is one 
demension, Vac is the second dimesnion and the array value is the fuel. Take 
this data for several points on the RPM curve then when the engine is running 
have it integrate the curve data and find the appropriate value for fuel? With 
an O2 sensor taking up the rear with corrections with are stored in some sort of
temp table?    Just a thought----- After all I'm using a PC (286 w/ 287) So I 
have all the horse power I need.