How does VVA work? VVA - Variable Valve Actuation The technology used by some Yamaha engines for improved power and economical use. Also similar to Honda's VTEC. At low RPM, the low lift cams are engaged, thus the valves only open in a short duration or low lift. The effect is better fuel economy and more manageable power delivery in normal riding. At high RPM, the "wild cams" gets engaged. These cams have long duration or high lift allowing more air/fuel mixture to flow through the combustion c

What is variable valve lift? What is variable valve timing? We're going to look at the valvtrain from a 2009 Audi 2.0L I4 Turbo engine to check out the differences. Variable valve lift is used to enhance performance depending on the RPM and load, while variable valve timing is typically used for emissions control (lowering combustion temperatures and thus reducing NOx), but also has performance and efficiency benefits as well. | Engineering Explained