Under the hood of the Infiniti QX50 resides arguably one of the most innovative new internal combustion engines available on the market today. The funny thing is however, you would hardly notice by just looking at it.
Buried under an intense collection of hoses, ducts, wiring and other umbilicals is the world’s first mass production variable compression gasoline engine.
The 2.0-liter VC-Turbo four-cylinder engine through a complex internal system of control shafts can continuously adjust its compression ratio spread from 8:1 to 14:1 and thus a displacement of 1997 to 1970 cc. If you really want to get inside and see what makes it tick, we have another whole video linked at the end and below.
In the here an now, looking down on the uncovered VC Turbo, it looks like a mess if we’re honest – hardly a technological tour de force. None the less, some of you will have one of these and be looking for all its important parts so here goes.
Both direct and port fuel injection to use either or both when they are best suited – horsepower or efficiency. There’s variable cam timing too that has a wide-range allowing for both an Atkinson or Otto combustion cycles.
Service points up first, the oil dipstick and oil filler cap are found deep below the engine’s sound cover. You could access them with it on, but it will be easier if you pluck it off as they reside deep inside the access holes if you don’t.
Like most cars, the brake fluid reservoir is up at the firewall on the drive side and easily accessed. The 12-volt battery is just adjacent to it on the right and further forward are the main fuse boxes. The majority of the ones we commoners will want to service are in the front box, the top released by four tabs.
Windshield washer fluid is up front on the driver side, not color coded like many vehicles but it’s there if you look for it. Coolant reservoir is on the upper passenger side fender area close to the shock tower. The air filter box is at the top rear of the engine, a bit of a reach to get to.
Following the air flow, the engine breathes through a snorkel at the front of the radiator support and pulls the air through the aforementioned filter box. It travels downward to the turbocharger mounted directly on the rear of the engine where the exhaust manifold is integrated into the head.
The air then routes back up over the top and down below to the air-to-air intercooler. From there it comes up from below and into the throttle body and composite plastic intake.
All said this variation of the MR20 DDT 2.0-liter VC-Turbo produces 268 horsepower and 288 pound feet of torque.