For better understand of this problem, let us remember main aspects of internal combustion engine principal scheme. This invention gets mechanical energy during the third stroke, when mixture of fuel and oxygen quickly inflames (nearly blasts) in the cylinder. The stronger this “blast” is – the bigger power pushes the piston, which transmits the force to the connecting rod and finally to the crankshaft. This results in the increase of torque and power as its derivative. If we want to gain a stronger “blast”, it is necessary to deliver more energy substrate in the cylinder – to bring a bigger amount of fuel and oxygen mixture there.
Approaches to chip-tuning mainly depend on motor construction. The first kind of improvement adjusts fuel system and increases the duration of injection period. The second kind implies changings in supercharging system. ECU software electronically control the exhausted emissions valve, providing prolongation of its closure period, which results in growth of turbine frequency rate and additional pressure rise. Both ways of improvement lead to increase of fuel and air delivery to the cylinder.
Furthermore, in petrol engines there is a possibility to affect ignition map, causing changes of spark angle. However, this parameter has great influence to the engine detonation durability (as a rule it is corrected automatically when the fuel quality is insufficient), and when the turbine is installed on petrol motor, one can get better power increase from manipulations with its operation protocol than from spark angle change. That is why chip-tuning present the most significant results on supercharged power units.