The first Nissan twin-turbo V6 to power an Infiniti model debuts in the 2016 Q50 sports sedan, the brand's top-selling model in North America.
“This all-new 3.0-L V6 twin turbo engine is powerful, fuel efficient, and lightweight,” Kyle Vargason, Manager of Infiniti Product Planning, told Automotive Engineering at the engine's global debut December 15 in Michigan. The first application is the 2016 Q50 Red Sport 400, a BMW M5 competitor targeted to reach dealerships in March 2016.
Based on Nissan's VR-series V6 launched in 3.8-L form on the 2007 GT-R, the new direct-injected engine is designated VR30DETT. It will be available with two performance ratings: 400 hp (298 kW) and 350 lb-ft (475 N·m), and 300 hp (224 kW) and 295 lb-ft (400 N·m). Both engines make peak power at 6400 rpm, with peak torque available from 1600-5200 rpm.
The aluminum 60º cylinder block features "square" 86 x 86-mm (3.39-in) bore and stroke dimensions, with thermal-arc-sprayed bores, The technology, also known as “plasma coating,” is claimed to reduce ring-to-bore friction by 40% and saves 3.8 lb (1.7 kg) compared with the outgoing VQ-series V6.
The all-new aluminum cylinder heads were thoroughly redesigned for boosted DI duty. They incorporate integrated exhaust manifolds, with close-coupled catalytic converters and compact twin direct-mount IHI turbochargers with twin air-to-water intercoolers. The cast-in manifolds allow the cats to reach operating temperature twice as fast as those of the old VQ engines. They also result in an 11.7-lb (5.3 kg) mass reduction versus separate manifolds.
An optical turbine speed sensor allows the twin-turbo system to perform up to 220,000 rpm at steady condition and up to 240,000 rpm at transient condition, Vargason claimed. He explained that the optical sensor, along with an electronically-controlled-and-actuated wastegate, provide a higher degree of boost control and improved response in transient conditions. Also helping to increase engine response time is a new electronic intake cam phaser.
To reduce weight, the lower oil pan, cam covers, and intake manifold are molded using an organic-derived reinforced plastic resin. As installed in the Q50, the new VR30ETT weighs in at 486.3 lb (220.6 kg) fully dressed. The turbocharger/intercooler system (which Nissan calls the CAC) accounts for 56.9 lb (25.8 kg). Sans CAC, the 3.0-L V6 weighs 39.1 lb (14.1 kg) less than the 3.7-L VQ-series V6 it replaces.
Moving to direct injection helps increase fuel economy by 6.7% versus the 3.7-L, Nissan engineers claimed. The VR30ETT will be manufactured at Nissan's Iwaki, Japan, engine plant.
The new Q50 also is available with a Mercedes-derived 208 hp turbocharged 2.0-L four, a result of Nissan's development collaboration with Daimler-Benz, or a 360-hp (268-kW) hybrid powertrain that combines a carryover (VQ series) 3.5-L V6 and a compact laminated lithium-ion battery pack with the JATCO JR712E one-motor, two-clutch hybrid 7-speed transmission.
Non-hybrid Q50s use a 7-speed electronically controlled automatic with manual shift mode and steering column-mounted magnesium paddle shifters.