VTEC and VVT-i are two of the most popular variable valve timing systems in the automotive industry. In this article we are going to give you a quick rundown on the two engine technologies and some of their differences and benefits.
Table of Contents
What is VTEC?
VTEC stands for Variable Valve Timing and Lift Electronic Control. It is an engine technology developed by Honda that improves engine performance and fuel efficiency. VTEC is designed to optimise engine performance at high RPMs by adjusting the opening and closing of the engine’s valves.
How does VTEC work?
VTEC works by using two camshaft profiles. One camshaft profile is used for low to mid-range RPMs, while the other is used for high RPMs. When the engine is running at low to mid-range RPMs, the valves are opened and closed by the low-profile camshaft. However, when the engine reaches a certain RPM threshold, the VTEC system switches to the high-profile camshaft, which opens the valves further and for a longer duration, allowing more air and fuel into the engine.
What are the benefits of VTEC?
The benefits of VTEC include improved engine performance and fuel efficiency. By optimizing the opening and closing of the engine’s valves, VTEC allows for a more complete combustion of fuel, resulting in more power and better fuel economy. Additionally, VTEC allows for a wider powerband, which means that the engine can produce power over a wider range of RPMs.
Another benefit of VTEC is that it reduces emissions. By optimising the combustion process, VTEC reduces the amount of unburned fuel that is released into the environment. This makes VTEC engines more environmentally friendly than traditional engines.
What is VVT-i?
VVT-i stands for Variable Valve Timing with Intelligence and is a technology developed by Toyota. It is a system that controls the timing of the opening and closing of the engine valves in response to the driving conditions. This allows the engine to operate more efficiently and deliver better performance.
How does VVT-i work?
VVT-i works by adjusting the timing of the opening and closing of the engine valves. The system uses oil pressure and an actuator to adjust the camshaft timing. The engine control unit (ECU) determines the optimal timing based on factors such as engine speed, throttle position, and load.
When the engine is running at low speeds, the camshaft timing is adjusted to keep the valves open longer. This allows more air and fuel into the engine, increasing torque and improving drivability. At high speeds, the camshaft timing is adjusted to keep the valves open for a shorter period, reducing fuel consumption and emissions.
What are the benefits of VVT-i?
VVT-i provides several benefits including improved fuel efficiency, reduced emissions, and increased power output. The system also allows for smoother operation of the engine at low speeds, reducing vibration and noise. Additionally, VVT-i can help extend the life of the engine by reducing wear and tear on the components.
Differences between VTEC and VVT-i
While both of these engine technologies work to improve engine performance, there are some key differences between them.
One of the main differences between VTEC and VVT-i is their approach to improving engine performance. VTEC is a more aggressive technology that is designed to improve high-end horsepower and torque. This is achieved by using a camshaft profile that is optimized for high RPMs. When the engine reaches a certain RPM threshold, the VTEC system engages, and the camshaft profile changes to a more aggressive one, allowing for increased airflow and more power.
VVT-i, on the other hand, is designed to improve low-end torque and drivability. This is achieved by varying the valve timing to optimize the engine’s performance at different RPMs. By adjusting the valve timing, VVT-i can increase low-end torque, which is useful for accelerating from a stop or climbing hills.
Fuel Efficiency Differences
Another key difference between VTEC and VVT-i is their approach to improving fuel efficiency. VTEC is designed to improve performance, which often comes at the expense of fuel efficiency. While VTEC can improve fuel efficiency in certain situations, such as highway driving, it is not always optimised for fuel efficiency.
VVT-i, on the other hand, is usually optimised for fuel efficiency. By adjusting the valve timing, VVT-i can optimise the engine’s performance at different RPMs, which can improve fuel efficiency. VVTI is particularly useful in stop-and-go traffic, where low-end torque is important for accelerating from a stop.