The 2016 Infiniti Q50 sports sedan offers a broad range of powertrains, but this car’s most alluring under-hood option is a brand new 3.0-liter twin-turbo V6. As with most good things in life, it was worth the wait.
Shosaku Ando, chief powertrain engineer in the large gasoline engine project group at Nissan has been developing this little dynamo for the past four years. Accordingly, he knows its secrets like nobody else.
Compared to other engines Infiniti has brought to market, this brand-new bent-six breaks a lot of new ground. It promises to be the most powerful and efficient engine Infiniti has ever built as well as its lightest and cleanest. Internally referred to as the VR, it builds on its predecessor’s success; The award-winning VQ-engine family has been showered with accolades since it first went on sale, winning a spot on Ward’s 10 Best Engines list for 14 years.
Launching in the Q50, this new twin-turbo 3.0-liter V6 is offered in two potencies, kind of like different doses of the same prescription. In its most basic form, it’s good for 300 horsepower and 295 lb-ft of torque, respectable figures to be certain, but it’s capable of much more than that. Red Sport 400 versions of this car gain an additional 100 ponies and 55 lb-ft of twist.
As for internal dimensions, bore and stroke are identical at 86 millimeters each, making this a perfectly square engine. Along these lines, the compression ratio measures a generous 10.3-to-1. Dressed for action, the whole shebang weighs less than 487 pounds.
Smooth running and powerful, this bent-six feels ready to pounce at the slightest tap of the accelerator pedal, which is exactly what Infiniti wanted.
“Our development concept is outstanding power and sharp throttle response,” explained Ando, things that made its VQ predecessor famous. “I think that feature is like the DNA of [the] VQ engine, and this VR is the successor to the VQ engine, so we have to achieve such features.”
Their conceptual heritage may be the same, but according to Ando, only one thing carries over from the VQ and that’s this engine’s 180-millimeter bore spacing, a figure they retained for manufacturing purposes. Other than this trivial figure, the VR is a clean-sheet redesign, though its pedigree is inspiring.
“We have a VR38 engine installed in the [Nissan] GT-R,” said Ando, but he admits the technology found in their new 3.0-liter unit is much more advanced. Integrated exhaust manifolds ensure its catalysts fire off quickly and help the engine warm up in frigid temperatures, gasoline direct injection cuts fuel consumption, electrically actuated variable valve timing responds quicker than hydraulic systems and is more efficient, the cylinder walls even have a thermal-arc spray treatment, which results in a “mirror bore coating” that reduces piston friction by 40 percent.
This latest VR V6 is loaded with little details that boost fuel economy and improve performance. Compared to the GT-R’s engine Ando said, “Basically our spirit is the same, quick response and outstanding power,” which is exactly what it delivers.
As its name suggests, the Q50 Red Sport 400 features a stable of 400 horses, while torque measures 350 lb-ft. Infiniti engineers achieved a 100-pony boost over the standard 3.0t by making a couple small changes, one of which is the addition of optical turbine-speed sensors. “This application is a world-first for a gasoline engine, but maybe half a year later, [the] Volkswagen Phaeton will apply this system,” said Ando. “It’s just a rumor.”
These instruments keep an eye on how fast the turbochargers are spinning, allowing the engine to push them closer to their maximum speed.
Regular 3.0t versions of the Q50 run 8.7 pounds of peak boost. However, the wick really gets turned up in Red Sport 400 models. They’re puffed up with 14.7 PSI, roughly 40 percent more.
Aside from the inclusion of turbine-speed sensors, there’s only one other difference between these engines. The 400-horsepower model features a second water pump in its cooling circuit to help keep induction temperatures in check. Other than this, these powerplants are identical, sharing the same block, heads, rotating parts and ancillary components.
As Ando mentioned, sharp throttle response was one of the main goals with this engine; it was something they had to achieve, though that’s not necessarily an easy task when turbochargers are part of the mix. To deliver, Ando said they applied a “very small diameter turbine and compressor. But in this case, we have to compromise that output power, so I apply the turbine-speed sensor and make full use of the turbine speed limit.”
Infiniti’s latest V6 engine is a winner, particularly in the Q50 Red Sport 400, delivering silky performance and a mountain of torque without any perceptible lag. It’s a powerplant that we can’t wait to find in more Infiniti products.
Discuss this story on our Infiniti Forum