16V vs. 20V?

coastdriftr · 25 Jun 2010, 03:32 am

what advantages do a 20 valve engine have over a 16 valve engine? i.e. in the case of the toyota 4AG series of engines.

Ahundred · 25 Jun 2010, 03:32 am

I've never been sure why, but automobile marketers have always marketed four-valve-per-cylinder engines by exhibiting the number of valves they have overall as opposed to simply the number of valves they have per cylinder. A twenty-valve engine has five cylinders with four valves per cylinder, a sixteen-valve engine has four cylinders. Five cylinder engines are pretty cool, they run real smooth-like. I didn't know Toyota made any. Get a car with one of those.

Starman · 25 Jun 2010, 03:33 am

All else being equal an engine with multiple valves will have a higher airflow rate and better fuel vaporization than one with fewer valves. In normal driving one would likely never know the difference, though. It's more of a bragging point when it comes to everyday driving.

unplugged · 25 Jun 2010, 03:40 am

the more valves an engine has, the more better flow it has. fuel and air would be able to enter the cylinders more quick and efficiently and the exhaust gases would be able to leave the cylinder more quicker and more efficiently. therefore reducing the load on the engine to force the air in and out and increasing fuel economy and performance.

wondering · 25 Jun 2010, 03:40 am

"ahundred" is mistaken the Toyota 20 valve is a 5 valve per cylinder (3 intake 2 exhaust) inline 4 engine NOT a 4 valve per cylinder (2 each) inline 5 engine. As others have stated 3 intake valves per instead of 1 or 2 means better "breathing" (volumetric efficiency) and thus horsepower.

16V vs. 20V?

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