The most significant mid-cycle revamp in the Nissan Pathfinder’s 30-year history provides the midsize SUV with a 6000 lb (2722 kg) towing capacity, a full half-ton improvement versus the 2016MY vehicle.
Chris Reed, Nissan North America's Vice President of Component Engineering and the Overseas Chief Vehicle Engineer for D-Platform SUVs, explained that the MY17 engineering changes were primarily focused on handling and performance. "The re-engineered V6 engine has a 10% horsepower and torque improvement without compromising fuel economy. And that higher performance output is balanced with a re-tuned steering system and an upgraded suspension system that improves the driving experience, even when towing,” Reed told Automotive Engineering at the Pathfinder’s recent media launch.
Boosting the maximum towing capacity by an additional 1000 lb (454 kg) called for significant enhancements to the powertrain and suspension, including 11% stiffer front shock absorbers, 7% stiffer rear shocks, with rear rebound spring rates increased by 25%. “We also added rebound springs to the front struts to improve the roll balance and body control,” said Reed.
The latest VQ-series 3.5-L gasoline V6 carries a 'DD' suffix, denoting direct fuel injection. With the new DI comes 11:1 compression ratio, up from 10.3:1 on the previous sequential multi-port injected V6. Air intake system revisions entailed software and hardware changes (including new fully electronic cam timing on the intake side) that improve airflow characteristics.
The result is greater peak power (284 hp at 6000 rpm) and torque (259 lb-ft at 4800 rpm)—improvements of 24 hp (18 kW) and 19 lb·ft (26 N·m), respectively, versus the 2016 engine. And the additional output comes 400 rpm lower on the rev range than the power and torque peaks of the previous engine. To reduce friction between the piston rings and the cylinder wall, the VQ35DD’s cylinder bores are cast with a molten iron surface layer, referred to by Reed as mirror bore coating. Used first by Nissan North America, this technology replaces the previous cast iron cylinder liners and yields about 3 lb (1.4 kg) of weight savings.
The new V6 mates to a third-generation Xtronic continuously variable transmission developed by JATCO. “As one example, this next-generation transmission’s optimizations helps keep the engine rpm stable while towing,” Reed said.
Engine cooling was a key focus during the new Pathfinder's development The truck's new "V-motion" grille opening was designed to boost airflow to the higher output V6 during towing. Said Reed: “It’s all about getting the right amount of air with the right pressure and flow through the engine to keep the components at the right temperature.”