Since its inception, it’s been pretty common knowledge that the BMW M235i was the best non-M BMW you could buy and, in many ways better than a lot of actual BMW M cars. Its combination of great steering, fantastic handling dynamics and just being the right size made it more fun than nearly any other BMW to drive. Now, BMW has announced that the M235i will become the M240i and will pack the Bavarian brand’s new B58 3.0 liter turbocharged I6 engine from the 340i. So BMW took the best non-M car and made it even better.

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BMW M235i

Developing 340 hp and 369 lb-ft of torque, the new BMW M40i is said to accelerate from 0-60 mph in 4.8 seconds with a manual and 4.6 seconds with the eight-speed auto. However, those are likely quite conservative numbers, as we’ve clocked the M235i at faster numbers than that with less power. So imagine somewhere in the low four second range in reality. But it isn’t the speed or power that makes the B58 engine so special, it’s the way it delivers that power.

First, there’s the noise. When testing the BMW 340i and its B58 engine back in October, I remarked that it was the best engine BMW had made in ages. It sounds brilliant, better than any other BMW not named “M2”, and it’s a sound that brings back memories of BMW I6s from a bygone era. It’s growly at idle, with a bit of a burble, and that burble turns into a metallic wail as the rev needle nears red line. It sounds like BMW M cars of old. It’s simply brilliant.

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BMW B58 engine

Then there’s the power delivery. It’s incredibly smooth, as if its cylinders are coating in double cream and it’s running on liquid silk. It’s the smoothest BMW engine in ages and it’s simply the best engine in its class, without question.

But on top of the noise and the silky smoothness, it’s downright powerful. It delivers instant thrust from idle and pulls hard until it hits the rev-limiter. And during no point does it ever feel turbocharged. It feels like a naturally-aspirated I6, the kind we remember from cars like the E36 and E46 M3.

So add that engine to the M235i and you have a car that most likely can’t be beat in its segment. While the M235i’s outgoing N55 engine was a fantastic engine, the new B58 is nothing short of brilliance and will make its new M240i replacement an absolute gem. The M235i was already so good that it threatened the M2’s relevance, so this new BMW M240i should really make decisions tough for potential M2 buyers. If you can’t get your hands on an M2 or simply can’t afford the extra money for one, fret not, because the best non-M BMW just got even better and will be as fun and enjoyable as you could ever want a car to be.