The Lexus RX 350 teams a 3.5-liter V6 engine with a six-speed Electronically Controlled Transmission with intelligence (ECT-i) for an output of 270 horsepower at 6,200 rpm. Intake and exhaust manifolds have been tuned for enhanced performance and fuel economy. Lexus maximized the torque output to better meet the needs of luxury crossover drivers. Ninety percent or more of the 248 lb.-ft. of peak torque is available from 2,300 to 6,100 rpm, an optimal range where torque is most utilized. An insulated engine cover, styled in the shape of two cylinder banks, conceals the V6 to help ensure a quiet cabin; easy-access points facilitate routine service.
Dual Variable Valve Timing with intelligence (VVT-i) is used to control both intake and exhaust camshafts independently, optimizing engine performance at all speeds and loads. Refinements to the valvetrain, including roller rocker arms and slimmer valve stems, reduce friction and weight to improve fuel economy. Also helping to enhance torque is the improved Acoustic Control Induction System (ACIS), which varies the intake runner length in response to engine speed and throttle position. The ETCS-i (Electronic Throttle Control System with intelligence) softens throttle response during initial acceleration for smoother takeoff and to help reduce wheel spin.
The RX 350's six-speed automatic transmission yields a quick shifting response with help from miniature high-flow linear solenoids that control transmission-fluid line-pressure. The torque converter uses a low-speed lockup damper to enable lock-up from second to sixth gear to help improve the fuel economy.
When applying the accelerator pedal rapidly during kick-down, the direct-downshift control allows the transmission to directly shift from sixth to third or fifth to second, skipping the intermediate gears to achieve the quickest response. Under normal kick-down pedal application, downshift control uses the intermediate gears to ensure the smoothest shift is attained. "Shift shock" is further reduced.
The Multi-Mode Sequential Shift Automatic Transmission allows the driver to shift manually when desired by first moving the gated shift lever to the "S" slot and then pushing it forward ("+") to up shift and backward ("-") to downshift. An Intelligent Shift Control sets shift patterns based on the vehicle speed and throttle position and estimates road conditions and driver input to automatically control the shift pattern. For example, when driving in hilly areas, this system can prevent unnecessary shifting. When descending inclines, the transmission prevents up shifts to achieve more engine braking.
The RX 350 AWD model features an electronically controlled Active Torque Control AWD system. Active Torque Control AWD uses an electronically controlled coupling ahead of the rear differential to vary torque distribution anywhere from 100:0 to 50:50 front to rear, depending on driving dynamics and road conditions. When accelerating, or starting off on a low-grip surface, torque is quickly provided to all four wheels. At steady speeds, torque is sent only to the front wheels, enhancing fuel efficiency.
To help provide handling agility and control, the AWD system increases rear-wheel torque when the vehicle's front tires start to lose traction and decreases rear-wheel torque when the vehicle's rear tires start to lose traction. On rough or sandy terrain, an AWD LOCK switch provides enhanced traction performance for low-speed maneuvering (if in LOCK mode, the system reverts to AUTO mode when speed exceeds 25 mph). To help prevent a tight corner-braking condition (shuddering) during low-speed cornering, the system reduces rear wheel torque.