The True Inner Working’s of Honda’s Awesome VTEC System: Video
VTEC stands for Variable Valve Timing & Lift Electronic Controlby Andrei Nedelea, on
In the engineering world, Honda is most famous for its creation of VTEC, a system that allows engines to excel at delivering good fuel economy, as well as high-performance all without forced induction. VTEC is really clever, but as the widespread adoption of turbocharging has changed the industry, it is not as important as it used to be - even Honda itself is only using it on the exhaust camshaft of its turbocharged cars these days.
How Exhaust-Only VTEC Works on the Honda Civic Type R
But what exactly is it?
Well, VTEC is essentially just fancy camshafts that have different size lobes; one set for efficiency, the other for power.
It can change between them depending mainly on oil pressure and engine rpm, as well as engine temperature. When a certain number of revolutions per minute is exceeded, say 4,000 rpm, and the engine is under load, it will automatically shift to the second pair of cam lobes which open both intake and exhausts valves sooner and keep them open for longer.
Later iterations of the system, dubbed i-VTEC, also incorporated variable valve timing to further improve engines’ elasticity, efficiency, and performance. But nowadays Honda has adopted turbocharging for more and more of its power plants, and with these new engines, it doesn’t really need to keep using VTEC.
How Old-School Honda VTEC Works
In fact, its 1.5-liter, turbocharged, four-cylinder engine doesn’t even have it anymore, and the fire-breathing Civic Type-R engine only has it on the exhaust cam. What this means is the turbocharger is supplying enough extra air that it negates the use for higher-lift lobes on the cam, yet they are still useful on the exhaust cam in order to allow for better gas flow out of the cylinder - this incidentally has a positive effect on building turbo boost, and the result is a very peppy and responsive engine.
There is still some lag in the latest Civic Type-R, but it is minimal compared to other cars.
Honda will probably figure out an even simpler way to achieve the same results as it is with having a VTEC exhaust cam, and in the near future it might completely give up its use as it fully embraces turbocharging for all its future gasoline engines.
Read our full review on the 2018 Honda Civic Type R.