Is the B58 engine the best engine from BMW?
I can feel metaphorical pitchforks being thrown at me as we speak. Yes, I really just suggested that BMW’s B58 engine – and the engine that comes in America’s entry-level BMW X5 – the best engine the brand has ever made. Yeah, it sounds a bit extreme at first, but listen to me.
The BMW B58 engine is remarkable. Its combination of attributes is unmatched among six-cylinder engines on the market. In fact, it may not have an equal among all the engines on the market. It is so good. Good enough to suggest that it is better than all of the glorious BMW engines that came before it? I will say it, but with a caveat. I exclude ultra-rare engines such as the McLaren F1’s S70 / 2 V12 engine. Only mainstream production engines are included.
What is the B58?
For those who aren’t consumed with BMW’s nerdom enthusiasm, let me introduce the B58 engine to you. It’s a turbocharged 3.0-liter inline-six engine that powers everything from the BMW M240i to the aforementioned X5 xDrive40i to the BMW 745e plug-in hybrid. Which brings me to its first attribute.
BMW is putting the B58 engine in almost everything it can. This is not unusual in itself, as the homogenization of automotive engines is nothing new, regardless of the brand. However, the breadth of capabilities of the B58 is staggering. It powers real performance cars, such as M240i, M340i, X3 M40i and Z4 M40i. It also powers standard luxury cars, like the BMW 540i, X5 xDrive40i, and it’s even good enough for the massively heavy X7 xDrive40i. And it’s even smooth and efficient enough to be used in plug-in hybrids, such as the BMW X5 xDrive45e and 745e.
Of course, there are plenty of engines on the market that serve more than one function, but none of them excel in all of them like the B58. In every application, the B58 engine feels perfect; as if it had been built for the sole purpose of being used in this same car. Drive the BMW 745e and it is almost impossible to say that its engine could be used as a performance, exciting and engaging car engine.
To be able to
When it comes to the fun stuff – performance cars and the like – the BMW B58 engine is absolute fun to use, mainly because of its power. In its M Performance specification (all of the aforementioned M40i models), it develops 382 horsepower and 369 lb-ft of torque. On paper. In the rear world, it feels like you have 100 more horsepower than that. Its pulling power is immense, capable of accelerating even heavy SUVs.
But it’s not just the power itself, but its delivery. There is torque throughout the rev range and virtually no turbo lag. Step on the pedal in any gear, at any rpm, and the B58 explodes, with a seemingly endless surge of power. Driving any car with a B58 engine is really special, because of the performance that awaits you at your right foot. Drive any other six-cylinder engine in its class, from any other manufacturer, and you’ll quickly realize how special the power of the B58 is.
You’d think an engine with instant response, zero turbo lag, and almost 400 horsepower would be rough and rough. But not the B58. It’s like replacing his engine oil with heavy cream. There is no negative NVH to speak of, just smooth and effortless delivery. Even in the middle of a conversation, with revs reaching their limit, the B58 never feels that smooth and sophisticated. He’s the Captain America of high-revving engines – he can do it all day.
It also works perfectly with the ZF eight-speed automatic transmission. BMW’s engine and transmission calibration is perhaps the best in the business, after perhaps only Porsche’s, and the B58’s inherent smoothness has a lot to do with it.
Noise and character
There are a lot of very efficient engines on the market, even in the price range of the B58. I’m thinking of Audi’s 2.9-liter twin-turbo V6, Alfa’s same-displacement V6 and even Cadillac’s new twin-turbo V6. However, none of them can match the character of the B58, with its harsh, metallic exhaust note. By the way, all three produce more horsepower and are offered in more expensive performance cars.
Is BMW’s B58 the best engine in the world? No of course not. However, BMW’s ubiquitous inline-six has one trump card up its sleeve: value. The B58 is available in affordable cars for a wide variety of enthusiasts. If you want a more special engine, you have to spend a lot of extra money on the car it fits into. The BMW M240i costs less than $ 50,000 and the M340i less than $ 55,000. You don’t have to spend a fortune to get an engine that feels more special than most of the other engines on the market.
The only other six-cylinder engine that can beat the B58, in terms of sound, character, power and feel, is Porsche’s naturally aspirated 4.0-liter flat-six of the Cayman GT4. However, this car is much more expensive and this engine is limited to super special edition cars.
In my opinion, even BMW’s S58 engine, the M-Division version of the B58, lacks the refinement of its cheaper sibling. I also like the sound of the B58 more, as it sounds a bit purer and less artificial.
BMW has made a ton of great engines over the years. Its sixties four cylinders were great for their time, the six cylinders that powered BMWs in the eighties and nineties were brilliant, and some of its V8s and V12s were killers too. However, honestly, I don’t think a single engine from the brand has ever matched the B58’s combination of power, performance, refinement, versatility and price. Internal combustion is going to be a dinosaur sooner rather than later, so we should all be celebrating the pinnacle of technology and the B58 is just that.