Most of our customers come to us for dyno-tuning because they are experiencing a problem with the way their bike is running. Perhaps it pings under acceleration, runs really hot, has a lean stutter or won’t idle properly. Maybe power appears to sign-off inexplicably in the mid-range or well below red line. Many complain they are running the exact same configuration of pipes, cams & engine management system as their buddy, but their buddy’s bike is noticeably faster.

This latter point is critical, because contrary to what might be presumed, no two configurations are exactly the same. Irrespective of the identical list of components, the aggregate or stacked result of manufacturing deviation in each component nets something different; and this unique product has its own needs when it comes to fuel & spark management.

Your engine is an air pump. The amount of air it pumps, under varying load conditions, determines its potential power output. There is a theoretical volume of air passing each combustion cycle based on a cylinders displacement; and then there is the actual amount of air that passes. The relationship between the two is expressed as a ratio known as volumetric efficiency or VE for short.

Your engine management system (ECM) knows all about VE. It must, in order to meter the correct amount of fuel. Thus, every ECM is programmed at the factory with a VE table for each cylinder.

The ECM is continuously monitoring throttle position, engine speed, and manifold absolute pressure; and it is continuously looking to its VE tables to determine how much fuel to meter at the given throttle position, RPM, and load.