DFI controler

[peter paul fenske]

Hi Michael


>1)sequential port fuel injection for 2.5l (iron duke) with direct

First off there is a factory FI for this motor. It ended up in the
tech IV with about 110 net hp. Uses throttle body and map sensor
However to get 300 gross HP is prob impossible without a turbo or
other add on. The iron duke is half a pontiac 301 which is based
on a mid fifties design. Albeit it was upgraded for the 80s with
headers roller cam ect. 


>I have been reading about the fuel maps etc. and have been wondering about
>this. Is it necessary to have a look-up table( I understand their
>function) Is it possible to simple run to various value from sensors (map,
>rpm, temp, etc.) through a math formula and be calulated "on the fly" or
>is this process to slow compared to a look-up table?  This would allow for
>a minor adjustment to a formula value to change the curve vs re-maping the
>eprom. 

Check out Ed Lan. article in circuit cellar. Yes you can use Map multiplied
by rpm to get a crude measure of air mass. Use breakpoints in the 
program to allow for major VE deviations. If you don't want to particularly
pass emissions and are not concerned about closed loop it ends up pretty
simple. Remember you want to end up with an injector pulsewidth for
all modes of engine operation which allows the proper A/F ratio

In the end tables are really quite simple. What you can do to 
approximate the table is to end up with a 14.7 to one AFR for
each load point. This can be aprox with the airmass calc. Then use
a separate table for enrichment for wot. 

Or you can go to a mass airflow sensor. This gives you airmass directly
although you may use a simple table to convert the sensor readings and
linearize them. Then a compensation for air temp with the necessary 
enrichment for wot.

Hope that helps:peter