Why Does the Current Honda NSX not Have VTEC? #BlogPost
Honda’s second edition of its lauded sports car, the NSX, breaks away from its predecessor in many aspects. Where there once was a stick shift, there is now only a nine-speed dual-clutch transmission. The original car had 3.0 and 3.2 L V6’s, both naturally aspirated, but the new car has a 3.5 L V6 that is aided by two turbochargers and three electric motors. This configuration transmits power to all four wheels rather than the two rears that the former car utilized. In size and weight, the newer car is larger and heavier, with the featherweight original being smaller.
What is most interesting, however, is that while this car’s predecessor had Variable Valve Timing and Lift Electronic Control (VTEC), this one does not. Honda added turbochargers, multiplied power output, and divided the power’s transmission, but why did it subtract VTEC?
The answer is simple: it does not need it.
VTEC works wonders by increasing both fuel economy and power through utilizing two different camshaft profiles; the first, more economy-minded profile is switched to the second, more performance-oriented profile typically from 4,200 RPM to 5,500 RPM. When one gets on the throttle, a VTEC-equipped has to transition from one profile to the next, which brings some delay. Since the power is focused more around the top of the power band, if the current NSX, which can rev to 7,500 RPM, had VTEC, then there would only be 2,000 RPM to 3,300 RPM for the performance profile to be active.
Instead of VTEC, Honda has three electric motors. Two of these control the front wheels while the third is a direct drive unit sitting between that potent V6 (which makes 500 horsepower alone) and the nine-speed gearbox. Offering full torque at a standstill (500 RPM for the direct drive motor), these motors provide motivation for the 3,868-pound Honda while the turbochargers spool up. Once these gain enough exhaust gases, the six pistons sprint up to the redline, with the motors masking engine lag as the paddles are pulled. Combined, both the engine and the motors make 573 horsepower and 476 lb-ft of torque.
The motors also provide a unique advantage in the form of torque vectoring. Since the front motors are separated from one side to the other and since there is a multi-plate controlled limited-slip differential at the rear, the NSX’s SH-AWD system can modify its direction through its distribution of torque.
The other issue with VTEC is that it is not optimized for this sort of application. Since this car is turbocharged, a VTEC TURBO system would have to be installed, but the technology can only support three displacement capabilities. These are 1.0 L three-cylinder engines, 1.5 L four-cylinder engines, and 2.0 L four-cylinder engines. As it currently stands, VTEC (in its VTEC TURBO guise) cannot be utilized because it does not support the NSX’s 3.5 L V6.
VTEC is an important milestone in Honda’s history because of how it made downsizing an engine something that did not need a turbocharger or a rotary engine to do so. It allowed taxes on such cars to stay cheap while providing high performance and returning good fuel economy. The system, as it is now, cannot support the current 3.5 L V6, and the engine would also be somewhat delayed because of the wait for VTEC to kick in. VTEC was beneficial on the old NSX with how it could go toe-to-toe with Ferraris while returning better fuel economy. The current NSX, however, is straying from the old to usher in the new. The NSX does not just want to beat its competition; it wants to shock them.