The N55 also ditches BMW’s twin-turbo setup for a unique dual-scroll turbocharger assembly with not one but two impeller scrolls. These reside at the end of a flow-optimized exhaust manifold which neutralizes opposing exhaust pulses and exposes the scrolls to a heavier 'impact' from the engines exhaust stream. In plain English, the turbocharger can capture more energy that would otherwise escape the combustion process as heat. It also helps the engine generate peak torque by just 1,200 RPM for fantastic response in city driving.
BMW's Valvetronic camshaft management system works away inside of the cylinder head to fine-tune engine breathing for maximized fuel economy and performance relative to driver intentions. The N55 represents the first time both Valvetronic and turbocharging have worked together in the same BMW engine, and enthusiasts are excited about the match-up.
It’s not just internal engine work at play here-- as the N55 also gets a less-greedy selection of support hardware and accessories that boost efficiency even further. For instance, the alternator only recharges the battery during deceleration and braking, and is otherwise decoupled from the engine’s belt drive. This saves fuel and lets more of the engine’s power make it to the road.
The water pump also engages on an as-needed basis, and even remains off after cold start-up until operating temperature is reached. This speeds engine warm-up, after which point the pump only moves as much coolant as is needed for any given situation. It can even run after shut-down to cool the turbocharger.
Additionally, a new 8-speed automatic transmission (yes, 8!) is now standard on gas-powered X5 models. It takes the improvements to cruising mileage and acceleration offered by the outgoing six-speed automatic to the next level, and it’s lighter than the unit it replaces, too.
What’s it all mean? The turbocharged X5 xDrive35i will soon give shoppers 40 more horsepower and 75 more lb.-ft of torque than the naturally-aspirated xDrive30i model it replaces, in spite of a notable improvement in fuel economy. Official numbers are not yet available, tough drivers can expect gas bills to drop by somewhere around 18 percent-- even with the added high-efficiency Bavarian sauce.
Simultaneously, drivers get to enjoy an exciting, punchy new engine that sounds sweet and reaches eagerly for its 7,000 RPM redline. For those excited about the N55 but not considering an X5, BMW says their latest powerplant will replace the three-litre twin-turbo unit in all models except ‘is’ designated versions of the 335 and Z4.
 |
| The appearance is still very much X5, just slightly fresher and more alert. (Photo: Justin Pritchard/Auto123.com) |
BMW's Valvetronic camshaft management system works away inside of the cylinder head to fine-tune engine breathing for maximized fuel economy and performance relative to driver intentions. The N55 represents the first time both Valvetronic and turbocharging have worked together in the same BMW engine, and enthusiasts are excited about the match-up.
It’s not just internal engine work at play here-- as the N55 also gets a less-greedy selection of support hardware and accessories that boost efficiency even further. For instance, the alternator only recharges the battery during deceleration and braking, and is otherwise decoupled from the engine’s belt drive. This saves fuel and lets more of the engine’s power make it to the road.
The water pump also engages on an as-needed basis, and even remains off after cold start-up until operating temperature is reached. This speeds engine warm-up, after which point the pump only moves as much coolant as is needed for any given situation. It can even run after shut-down to cool the turbocharger.
Additionally, a new 8-speed automatic transmission (yes, 8!) is now standard on gas-powered X5 models. It takes the improvements to cruising mileage and acceleration offered by the outgoing six-speed automatic to the next level, and it’s lighter than the unit it replaces, too.
What’s it all mean? The turbocharged X5 xDrive35i will soon give shoppers 40 more horsepower and 75 more lb.-ft of torque than the naturally-aspirated xDrive30i model it replaces, in spite of a notable improvement in fuel economy. Official numbers are not yet available, tough drivers can expect gas bills to drop by somewhere around 18 percent-- even with the added high-efficiency Bavarian sauce.
Simultaneously, drivers get to enjoy an exciting, punchy new engine that sounds sweet and reaches eagerly for its 7,000 RPM redline. For those excited about the N55 but not considering an X5, BMW says their latest powerplant will replace the three-litre twin-turbo unit in all models except ‘is’ designated versions of the 335 and Z4.
 |
| The new makeover focused mainly on the powertrain and X5’s well-loved cabin. (Photo: BMW) |