’15 Lexus NX on sale in U.S. later this year.
NX Turbo Mill Lexus First…Sort Of
The NX 200t’s engine is an all-new design for Lexus, although it benefits from knowledge gained in an experimental turbocharged 4-cyl. done 10 years ago, NX chief engineer Takeaki Kato says.
The all-aluminum, 2.0L I-4 makes 235 hp and 258 lb.-ft. (350 Nm) of torque, on par with most competing models but slightly trailing theX3, one of the two vehicles benchmarked for the NX, which has a 2.0L turbocharged 4-cyl. making 240 hp and 260 lb.-ft. (353 Nm) of torque.
The best-selling entry-luxury CUV in the U.S., the Mercedes-Benz GLK, tops the segment in output, thanks to its naturally aspirated 3.5L V-6 that churns out 302 hp and 273 lb.-ft. (370 Nm) of torque.
The NX’s 2.0L turbo adds a new form of variable valve timing, VVT-iW, with the W standing for “wider,” as it allows the cam phasing to operate over a broader range. Under lighter loads, the engine can operate in Atkinson cycle, leading to better fuel economy, while in more aggressive driving the engine is in Otto cycle for improved torque.
But real-world torque is lacking, as the NX in our tests hesitates at step-off, further dinging the sporty claims.
While Lexus says peak torque can come as soon as 1,650 rpm, it feels closer to 3,000 behind the wheel.
This is a stark contrast to the2.0L, a 2-time Ward’s 10 Best Engines winner for its lack of turbo lag and feels-like-it 1,250-rpm torque peak.
The Lexus NX 300h hybrid, which the automaker expects to account for less than 10% of total NX U.S. sales, uses the ES 300h hybrid’s 2.5L Atkinson-cycle 4-cyl. and 244.8V nickel-metal-hydride battery.
However, as it is available in an all-wheel-drive configuration, the NX 300h adds a third motor to drive the rear wheels. As in the ES, the NX’s first and second motors start the engine and drive the front wheels, respectively.
Still, as with alland Lexus hybrids, driving solely on electric power is elusive above 20 mph (32 km/h).
The extreme tamping down of NVH is welcome in the NX 300h, as the sound of a motor whining isn’t particularly desirable.
The differences between the available driving modes, Eco, Normal and Sport, also is greatest in the NX 300h, with Sport resulting in a more eager tip-in and firmer steering feel.
The NX is “loosely based” on theRAV4 architecture, with just 10% carryover parts, Kato says. The same suspension geometry is shared, as is the front floor, dash panel and exterior rocker panels.
The improvements made to the platform, and body, largely are responsible for the tomb-like silence in the interior.
The NX boasts greater levels of rigidity and stability thanks to touches such as a front suspension tower that is joined to the cowl with thick-plate steel; ample amounts of body adhesive between the front pillar and dash panel and the front and rear door openings; laser-screw welding between existing spot welds; and more spot welds, at the back-door opening and No.3 cross-member, Lexus says.
Underbody areas getting more attention include the front bumper, which has been reinforced, and the rear-suspension member brace, now thicker and more-securely mounted.
But Lexus wanted a quieter CUV still so it adds urethane insulator panels in the hood and urethane liners in front fender while thinning out door frames.
The MacPherson-strut front and double-wishbone rear suspensions give a relatively athletic ride, as a slew of measures are taken to boost stability and ride comfort, such as the addition of rigid front and rear stabilizer bars to limit body roll in corners.
But the U.S.-spec NX lacks the adaptive suspension it will carry in some overseas markets. Without it here the CUV won’t have the same canyon-carving credentials of the X3 and Q5.
Not surprisingly, fuel economy is most impressive in the NX 300h, averaging 42 mpg (5.6 L/100 km), obliterating our AWD tester’s projected 32 mpg (7.4 L/100 km) combined rating but reflective of stop-and-go driving in this resort town.
Our next-best number is a not-shabby 36 mpg (6.5 L/100 km) in an AWD NX 200t F Sport, which is projected to average 24 mpg (9.8 L/100 km). A mostly high speed, limited-stop route helps here.