Wards Auto is the group that puts together the Best Engines awards. Those that follow the Wards awards (yes, that sounds awkward to me too) know that BMW is a perennial winner. The Best Engine awards is just one of many things that Wards does. Today, the Wards Auto Engine & Technology Update showed up in my inbox, and it included a tech heavy discussion of the new B58 engine that powers the 340i.
At first, it doesn’t seem like much is different. It’s still a 3 liter I-6 with TwinPower technology, but under the skin, a lot is going on. The first item that caught my attention is that it sports a new water-to-air intercooler. While there is a lot to debate about the pros and cons of W2A IC technology, there is no arguing over the fact that these greatly reduce compressed intake-air volume. For the non-techies, this means reduced turbo lag or a more responsive engine. The turbo has larger turbine and compressor wheels (6% and 10% respectively) that result in up to a 20% increase in boost pressure! Compression is up a bit, as well as displacement. All this results in 20 hp and 30 ft-lb increases, peak power is now 320 HP and 330 ft-lbs is on tap from 1380 to 5000 rpm. That’s some serious “area under the curve” for sure. These are changes you really can feel.
To get further into the high-tech details, this is a closed-deck design. This means the water jackets are closed at the top of the block. Harder to cast for sure, but more rigid. This increased strength allows for thinner cylinder walls that improve both warm up and heat conduction. Improved warm-up is better for emissions, and better heat conduction means that the engine should take full-throttle abuse better than the outgoing (and really wonderful) N55 this replaces. Another interesting tidbit is that the engine has a blankie! No, I’m not kidding. It has an insulating cover to retain heat for up to 36 hours. The claim is that this improves start-up emissions and performance. (ECUs run the engine differently at start when cold and when warmed up. This will reduce, and some cases eliminate, the use of start-up engine maps.)
This is the first I-6 of the BMW modular engine family that started with the 1.5L and 2.0L mills that showed up in the MINI line earlier. This is important for relatively low volume producers like BMW so that engineering costs can be spread out over more engine variants, allowing BMW to stay at the forefront of engine technology like they always have, which many of us take almost for granted.
There’s more tech details in the Wards article, and if you’re interested, you can read it here.