What delta load is
In ESP's transient throttle tuning, delta load is how far the throttle position changed during a 10 millisecond window. In other words, it's a measure of throttle speed rather than throttle position.
Two examples make it clear. If you stab the pedal and the throttle position jumps 12% in one 10 ms window, delta load reads 12%. If you roll gently into the throttle and it only moves 2% in the same window, delta load reads 2%. Same pedal, same end position perhaps, but very different rates, and the engine needs very different amounts of extra fuel for each.
Why it matters for tuning
Transient enrichment is scaled by how fast the throttle moves, because a fast opening causes a bigger, sharper lean spike than a slow one. Delta load is the input that tells the ECU which situation it's in. When you tune the rate table, you're really deciding how much of the enrichment amount to give at each delta load.
A few practical tips:
- Log delta load and lambda together, then do a range of slow and fast throttle movements. You'll see which rates cause a lean dip.
- Small delta load values near zero are normal wobble from your foot and the sensor. Your dead band should sit above those so they don't trigger fuel.
- Since delta load is a percentage over 10 ms, a noisy throttle sensor shows up as random small values. Fix the signal before tuning around it.
For how the rest of the function fits together, see our Elite transient throttle article, transient throttle enhance and asynchronous vs synchronous enrichment.
