One of the most commonly used terms by Honda enthusiasts around the world, VTEC is Honda’s variable valvetrain technology. VTEC technology in the mid 90’s was the cornerstone of Honda and Acura performance, and today it lives on in the K series of engines as i-VTEC. Whether you are looking to complete your Honda engine swap, build a reliable LS/VTEC engine, or troubleshoot VTEC, learning how VTEC works can help.
There are many different components that make up the VTEC system. The Honda VTEC stands for Variable Valve Timing and Lift Electronic Control. While it seems like a simple technology overall, it’s actually quite complex and has several different factors to it. If you own a Honda without VTEC currently, converting to VTEC or assembling your VTEC engine is easier once you learn how VTEC works.
How VTEC works FAQ
What is VTEC? – Honda’s innovative variable valve technology is something that is found in many of today’s late model vehicles. In simple terms it’s the ability to take advantage of low RPM scavenging and emissions, while increasing airflow through the cylinder head at high RPM.
How does VTEC work overall? – Based on an electronic signal sent from your Honda ECU, there’s a solenoid that activates VTEC. Once the VTEC solenoid in your Honda is activated, it uses oil pressure to push an engaging pin through your valvetrain. This activates the larger lobe of your camshaft, which increases duration and extends lift of your valves.
What this does is allows your Honda engine to run efficiently and with low emissions at part throttle and low RPM operation. When VTEC kicks in, the larger lobe takes advantage which allows you to gain more performance.
What’s the first VTEC engine? – One of the earliest implementations of Honda’s VTEC system was the 1991 Acura Integra GSR. The DA Integra was the first affordable production Honda to use the technology and it changed the landscape of sport compact cars forever.
How VTEC works electronically – VTEC Honda ECU’s can be modified or chipped, and there’s also several piggyback computers that can help you adjust or modify VTEC. Once your Honda VTEC engine reaches a certain engine speed, the ECU activates the VTEC solenoid. When you are installing or converting to VTEC, you’ll need a VTEC pressure switch and solenoid to match the engine computer.
in the DOHC VTEC Honda engines, both the intake and exhaust cams control three lobes per cylinder.
What happens when VTEC isn’t engaged? – When your engine is normally operating but under the RPM range in which VTEC kicks in, the center lobe or big lobe is supported by the Lost Motion Assembly. This mechanical unit provides the slack to support the big lobe until your engine reaches the desired RPM to engage VTEC. Learning how VTEC works is important if you need to service your LMA in your DOHC cylinder head.
I have a non-VTEC engine, what can I do to improve performance? – If you own a Honda or Acura without VTEC, the good news is swapping an engine with VTEC isn’t hard to do. Conversely you can also build a LS/VTEC hybrid which involves bolting on a VTEC cylinder head and using the matching ECU.
What will change with how VTEC works ? – The next generation of VTEC engines is the K series engines, which use i-VTEC. This technology utilizes different camshaft phasing, and uses a camshaft gear to adjust intake camshaft phasing on the fly. This helps improve and optimize overlap and maximizes fuel efficiency and horsepower. It’s also known as Intelligent VTEC because of this design.
There is already plans and talk of the next stage of VTEC evolution. Termed a-VTEC, or advanced VTEC. According to those who know how VTEC works and how Honda plans to evolve the variable valve technology, the camshaft lift will be continuously variable. This promises to be the next evolution and step in engine efficiency and design, not only for Honda but for all combustion engines.
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