Engine Load

This is a bunch of clips of information I have found on engine load:



Load is measurement of how hard an engine is working which is measured in percent. Coasting down hill is considered very low engine load. Pulling a weighted trailer uphill is considered high engine load.



Modern EFI has a broader title called Programmable Fuel Management Systems which comprise of components whose main function is to supply a mixture of fuel and air to the engine that can be easily ignited by spark to produce reliable efficient power. The main factor that chooses which engine management system to use is AIR FLOW. Air flow is the biggest unknown factor when calculating fuel ratios and timing curves. Air flow is so unpredictable that people get grant money to study wind tunnels. To decide which fuel management system to use depends on how unpredictable the air flow into your engine is.

There are 2 different modes fuel management systems can operation in:
Open-Loop
Open loop defines the engine operation when the fuel ratio is calculated with consideration to only input signals from the main sensors in the program style (MAF / SD / VAF / AN)
Programmable fuel management systems can be operated in 100% open loop very effectively.
Closed-Loop
Closed loop defines the engine operation when the fuel ratio is calculated with consideration taken from the main sensors and feed back sensors like the exhaust oxygen sensor (HEGO). Closed loop operation is devoted to emissions, economy, and a Stoichiometric fuel ratio of 14.7:1
Programmable fuel management systems can not dominantly rely upon closed loop operation without severe engine damage, performance loss, or other problems


"load %" is VE scaled by the load at sea level table.
The scaling is why the EEC tabled are indexed by % load. The idea is to scale across the RPM range so your engine is capable of about 100% everywhere.
At max load if your load % is 100% + / - 10% your table is OK.
Walt

Theory: The load_scaling_sealevel table is the theoretical VE curve for your engine.
Cookbook.
1) Set the CID back to what it is supposed to be.
2) Data log your percent load and a WOT run.
3) At each RPM in your load_scaling_sealevel table look at your %load. If your %load data logged is > 100%, increase the value in the table. If the %load is < 100% decrease the number in the table.
Example. Suppose you have 3500 RPM / .73 in the table, and suppose at 3500 RPM you see 125% in your data log. Then edit the table to make 3500 RPM set to .73 * 1.25, i.e. .91.
In practice, you should easily be able to achieve WOT load > 90% and < 110%. FWIW, I actually change the RPM points to accommodate the slightly different shape of my VE curve.
Walt