It can be said that VTEC, the original Honda variable valve control system originated from REV, revolution responding type valve pausing mechanism, announced in 1983. Receiving the demand for high power for sports bike engines at that time, prior study was started to reconcile high power in high revolution range and excellent drivability and high efficiency from idling throughout all ranges. An epoch-making variable valve system came into being, which enables to switch over from two valves to four valves. This technology later developed into the variable valve timing mechanism, VTEC (variable valve timing and lift electronic control system), which forms the nucleus of automobile engines.
REV born from aiming at reconciliation of 200PS per liter and low revolution range performance
Honda CBR400F equipped with REV, marketed in 1983 Faced with the demand for high power for sports bike engines, a preceding study started off on the assumption of 200PS performance per liter and the development of mass production engines with drivability from the same idling as before. The assignments for the project were to achieve the target power performance and come up with countermeasures against power drop in low speed revolution range and improper idling. It was revealed in the analysis of these issues that the large bore ports for achieving high revolution and high power and for reducing air inlet resistance and the intake and exhaust system with a pleural number of intake and exhaust valves hindered obtaining good idling and low and medium speed revolutions.
An experiment conducted by forcibly stopping several multiple valves made it possible to confirm the stability of idling and a dramatic improvement in the power of low and medium speed revolution range. This was the starting point for the development of valve pausing mechanism (REV: Revolution-modulated valve control), which was applied to the CBR400F in 1983.
REV born from aiming at reconciliation of 200PS per liter and low revolution range performance
Honda CBR400F equipped with REV, marketed in 1983 Faced with the demand for high power for sports bike engines, a preceding study started off on the assumption of 200PS performance per liter and the development of mass production engines with drivability from the same idling as before. The assignments for the project were to achieve the target power performance and come up with countermeasures against power drop in low speed revolution range and improper idling. It was revealed in the analysis of these issues that the large bore ports for achieving high revolution and high power and for reducing air inlet resistance and the intake and exhaust system with a pleural number of intake and exhaust valves hindered obtaining good idling and low and medium speed revolutions.
An experiment conducted by forcibly stopping several multiple valves made it possible to confirm the stability of idling and a dramatic improvement in the power of low and medium speed revolution range. This was the starting point for the development of valve pausing mechanism (REV: Revolution-modulated valve control), which was applied to the CBR400F in 1983.
