Optimizing Race Engine Performance One Cylinder at a Time

Performance of multicylinder engines is dictated by the sum of the contributions from the individual cylinders, each of which must be optimized to maximize the total output. Cylinder-to-cylinder imbalance causes each cylinder to operate differently, making individual-cylinder optimization a challenge. Unfortunately, cylinder-to-cylinder imbalance exists in all multicylinder engines, even those in which careful steps are taken in design and manufacturing to prevent it. While optimizing each cylinder of a multicylinder engine in high-volume production applications is not feasible, it is feasible in racing applications and can provide a significant competitive advantage.

This paper investigates causes of cylinder-to-cylinder imbalance and discusses techniques to optimize race engine performance one cylinder at a time through the systematic optimization of individual-cylinder intake valve closing, spark timing, and compression ratio.