You stated that the fuel is mapped by throttle position or boost versus rpm, but why is there no load input in the setup. Does the stock computer take care of that on both applications? On an N/A setup you would still need to read off of the map sensor in order to know what the load is not just rpm and throttle position. In a boosted scenario you would still have to know what the throttle position is to truly know load values not just the boost pressure.
Anyone care to expound on this? I would love to be educated on this.
To directly answer your question - you already stated the answer that the stock computer takes care of this on both applications.
I can't speak exactly to how each manufacturer creates its electronics or the internal complexities of the ECU, but this is generally speaking:
The "load" term for fueling is basically a misnomer and not a factor in the operations of the ECU. Purely it would be asking the ECU to determine how much resistance is being applied to the rubber track belting....there are no sensors here and the ECU cannot figure that out. It is a box that relies on electrical signals and information sent to it from sensors. Water temp, MAP, IAT, crank angle, throttle position, etc. are a few of these sensors. It then references a series of tables (sometimes a 5+ dimensional combination of %TP with RPM with MAP with IAT with perhaps DET sensed condition) to calculate what output is sent to the injectors.
It will also probably have the ability to the calculate outputs based on "delta" of each of the sensors. That would be the blips of the throttle within a specified time interval (10% change in throttle within 3ms for example)
But none of these input a true "load" parameter to the ECU. Effectively all of the combined sensors are what send information to the ECU allowing it calculate its proper output.
If there were a direct conversion to simulate load, that might come from the condition where more throttle (%TP) is required in heavy wet snow to get the sled moving than an just idling down a hardpack trail. The input that the ECU would see is still just the %TP.
Where this all boils down to is what the ECU is outputting to the sled. It has taken account of any sort of condition that the sled is being exposed to by compiling all data and then fueling the engine properly.
The Power Commander only piggybacks off of what the ECU has already done (in this case - it has figured out how much "load' is on the sled and sent out its pulse accordingly). Then, if we desire an increase in fuel at a point in the map, we insert a positive number in the map.
The tables in the Control Center software allow you to do both conditions - if I did not make that clear before I apologize. With a boosted application, you would have Both fuel tables available (one for RPM vs %TP, the another for RPM vs Boost). This is effectively what the ECU is doing as well - finding a single cell between a series of tables under a combination of operating conditions to pick out a duty cycle to deliver.
Pair the PCV with an ignition module and your would have another set of tables at your hands for tuning. Still, under all conditions, these tables are piggybacking off of the ECU after it has done all the processing of data - and then we alter the delivery to the engine (spark timing or injection amount) to suit our needs in the modified form.
This may be long-winded, but as you can see the level of sophistication in an ECU far exceeds what can be conveyed through words on a screen. I hope that this helped clarify things to some degree...
Regards,
~T.J.
