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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 ...
For the rest of this story, Everything You Need to Know About Infiniti’s New 3.0-Liter Twin-Turbo V6 please visit

5,401 Posts
Re: Everything You Need to Know About Infiniti’s New 3.0-Liter Twin-Turbo V6

Nope, not everything. I want to know why GM and Ford's 3.0T engines are both in the 400/400 range while Nissan manages only 400/350?

A real car blog would have anticipated such an obvious question.

Mercury C557
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Re: Everything You Need to Know About Infiniti’s New... 2 Liter

Infiniti rolls out industry-first variable compression engine
- Richard Truett - November 16, 2017

PHOENIX -- When the next-generation Infiniti QX50 crossover arrives next year as a 2019 model, it will be powered by a 2.0-liter turbocharged four-cylinder engine introducing a technology never seen before in a regular production vehicle: variable compression.

Under development at Nissan for 20 years, the Variable Compression – Turbo -- VC-T engine -- has a device that changes the distance the pistons travel in their cylinders by as much as 6 mm, or about a quarter of an inch.

It's an idea that automakers, such as Saab, and engine developers, including AVL, have tried to perfect over the years. The reason: Varying the compression ratio has the potential to offer dramatic improvements in power and efficiency.

Shinichi Kiga, Nissan's chief powertrain engineer, says Infiniti's VC-T engine is expected to deliver a combined city-highway EPA-rated fuel economy gain of 27 percent over the QX50s's outgoing 3.7-liter V-6. The VC-T engine is rated at 268 hp and 288 pound-feet of torque. Kiga says the 2019 QX50 will reach 60 mph almost one second faster than its four-cylinder competitors.

Infiniti last week allowed a few reporters to drive early pilot-build 2019 QX50s at the company's test trackhere. The VC-T's power and refinement were impressive. The technology works in such a manner to make it invisible to the driver. There are no buttons to press, no switches to turn and no strange noises, vibrations or sounds -- just smooth, abundant power and a pleasing, performance-tinged growl from under the hood.

How it works
The pistons in all of today's automotive internal combustion engines travel the same distance up and down in the cylinder, regardless of speed and vehicle load. The pistons are connected to rods that are mounted to the crankshaft. The engine's compression ratio is fixed and is determined by the amount of space above the pistons when they are at the top of their travel. The smaller the space above the pistons, the higher the compression ratio and the greater the engine's power output.

New layout
The Infiniti engine's layout is the first major change to the system in more than a century. The pistons in the VC-T engine are connected to rods that are attached to one end of an elliptic device Nissan calls a multilink. The multilink is mounted on the crankshaft where the connecting rods normally go.

The other end of the multilink has a short rod that is connected to a shaft. An electrically controlled actuator twists the shaft, causing the multilink to tilt up or down slightly. When the end of the multilink closest to the piston is tilted up, the piston travels to the top of the cylinder. That is high-compression mode, 14.1.

When the multilink tilts down, the piston's travel in the cylinder stops before it reaches the top.

This lowers the compression ratio to 8.1, but because the turbocharger kicks in at the same time, the engine's power output increases. The turbocharger pressurizes each cylinder with a denser mixture of fuel and air, which increases power.

"Variable compression solves the age-old problem of compromise," says analyst Dave Sullivan of AutoPacific, a consulting firm. "Automakers have the task of meeting increasing emissions regulations and tightening fuel economy standards while consumers want more power. They have to dial down the compression to make everyone happy.

"Nissan's variable compression engine should appease the enthusiasts as well as those concerned with fuel economy."

Robust target
Kiga said Nissan has long known that its multilink mechanical system of varying piston travel would not just work but also be robust enough for a production engine. The reason for the 20-year gestation is that engine-control technology was not yet advanced enough to manage the complex system.

"Control technologies helped us accelerate the development," Kiga said.

The engine uses nearly all the advanced technologies found in today's production engines. In addition to the turbocharger, the VC-T has both port and direct fuel injection, variable valve timing and a cooling system with four circuits. All of these systems provide inputs to the engine's computer, which runs a fast-spinning electric motor that operates the actuator arm that changes the piston travel.

The VC-T adds cost but is less expensive than a diesel engine.

The VC-T engine, Kiga says, is about 10 percent more expensive to produce than a regular 2.0-liter turbo four-cylinder engine. And although the VC-T has more moving parts than other turbocharged, four-cylinder engines, Kiga says it produces less friction. One reason is because the piston travels straight up and down in the cylinder, eliminating side forces that cause friction.

The current QX50, with its 3.7-liter V-6 engine, has a EPA fuel economy rating of 17 mpg city, 24 highway and 20 combined. When the new QX50 goes on sale, the combined fuel economy should be around 26 mpg, about what a diesel-powered vehicle of the same size would achieve, but without a lot of the emissions-system complexity.

The VC-T engine will be the only one offered in the QX50, and it will be available with just one transmission, a continuously variable automatic.

'Longer legs'
Although the Infiniti VC-T engine appears to be a significant advancement of the internal combustion engine, it may not have a huge impact, as governments around the world crack down on internal combustion engines and as automakers gear up to sell electrified vehicles.

"The 2.0-liter turbo has essentially replaced the 3.5-liter V-6. It's a very crowded space in which to set yourself apart," said Sullivan. "Combined with the continually variable transmission, the VC-T engine could yield some impressive fuel economy numbers. But with the relative stability of low fuel prices, it may not mean much to QX50 buyers. The immediate impact may not be felt with the QX50. But this technology only gives the internal combustion engine longer legs."

While the VC-T's performance and refinement in the test QX50s were outstanding, perhaps a downside for potential buyers is that the engine requires premium gasoline, which was averaging $3.09 per gallon, according to AAA, 52 cents more per gallon than regular.

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