What is i-VTEC?

[wynode]

Over time Honda have implemented a few variations of the VTEC system and have managed to achieve some great results. The most common VTEC system is the DOHC (Double Overhead Cam) system where each set of valves (Intake and Exhaust) has its own cam. DOHC VTEC configuration is optimised for high power output, and is capable of making upto 88kW per litre (as found in the current S2000).

The second impementation of VTEC is that of SOHC VTEC where both sets of intake and exhaust valves are run via a single cam. This mechanism is not for performance but for economy, while still making good power for practical everyday use. With SOHC VTEC, only the intake valves benefit from higher lift and not the exhaust valves.

The latest impementation of VTEC is that of i-VTEC where the system allows continuasly variable valve timing over the rev range (presently only on the intake cam) which allows for upto 6kW more at peak power with improved torque and fuel efficiency.

i- VTEC also has the added flexibility that it can adjust intake cam timing depending on engine load using a combination of inputs from the TPS, vehicle speed and vacuum readings.