DP: I did an adjustment to the fuel pump yesterday.
How do I explain it, hmm. There is a pin inside the top of the fuel pump which rests on top of a spring. The pin has a wedge cut out of it, and as the boost pushes the pin down against the spring, the wedge increases the fuelling in accordance with the boost.
You can lift this pin out and turn it 90 degrees so that the steepest angle is used. The steepest angle isn't used in the factory setting.
Basically, the fuelling increases faster as it boosts, so the boost pressure also increases faster. Result - better throttle response and OMG fast acceleration! My boost gauge just shoots up to 16-17psi almost instantly and just stays there!
EDIT: Watch
for a better explanation. It's the same Bosch VE fuel pump, but fitted to a Dodge Ram with a Cummins engine.