The single intake valve per cylinder provides better swirl of fuel/air inside the cylinder, which is the same effect produced by high port velocity. This swirl supports better torque production at lower rpms. But the obvious downside will be less overall airflow at higher RPMs, which is where the 4- and 5-valve designs really shine. Again this is keeping with older 80s/90s engine technology (before runner shutoff and cam phasing).
The strange thing is that my 1995 Corvette (pushrods/2 valves per cylinder) has the same 5500 RPM redline as my 2006 Tacoma (DOHC/4 valves per cylinder). I really thought that a DOHC design with less reciprocating mass would provide a higher redline. But whatever.
Although the Corvette has the benefit of higher compression and premium fuel, the Tacoma still has a higher specific output for HP. TQ is about the same per liter between the two. Umm... sorry for digressing.
The strange thing is that my 1995 Corvette (pushrods/2 valves per cylinder) has the same 5500 RPM redline as my 2006 Tacoma (DOHC/4 valves per cylinder). I really thought that a DOHC design with less reciprocating mass would provide a higher redline. But whatever.
Although the Corvette has the benefit of higher compression and premium fuel, the Tacoma still has a higher specific output for HP. TQ is about the same per liter between the two. Umm... sorry for digressing.
