BMW 3 Cylinder Turbo Engine (B38) Review by Autoblog

[Jason]

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BMW 3 Cylinder Turbo Engine (B38) Review by Autoblog

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Autoblog shares their review and impressions from some time behind the wheel of a 1 Series powered by BMW's new 1.5L 3 Cylinder TwinPower Turbo gasoline engine (the "B38" engine).

This is the engine you will see in many of BMW's forthcoming FWD models, including the recently revealed Concept Active Tourer, and MINI models.

In this particular application - in a prototype F20 1 Series, the B38 is quoted at 175hp @ 5000 rpm and 200 lb-ft torque @ 1500 rpm. The officially quoted 0-62mph (0-100kmh) time is 7.0 seconds. How does it drive and feel though? According to Autoblog:

We took a few laps of the setup course in this rear-wheel drive hatchback, trying various calibrations of the throttle, gearshifts, and so on. The first thing that became apparent is that BMW has been working hard on making this three-cylinder still sound like a Bimmer that BMW fans would happily buy instead of a cracking four-pot. Engineers on hand wouldn't go into exactly what has been done with the manifold or pipes, but the prototype sounded really fine to us. And two- and three-cylinder engines definitely have their own alto/baritone note. Add the twin-scroll turbo cranking up to 14.5 PSI of boost pressure, and all we can say is that the sound is uniquely pleasing.

Another issue, especially with three-cylinders, is vibration mainly from fore-aft jiggling along the axis of the cylinder bank and crankshaft. This can also sometimes create an almost pleasing massage for the feet and butt, but you really don't want this going on. The engineers in this case have designed a counter-spinning balance shaft that passes through the crankcase beneath the crankshaft. It works and the engine proved smooth and responsive throughout all the types of driving we experienced.

Our transmission was the ultra-efficient eight-speed automatic, whose many shorter gears succeed in mating well with the potentially uppity little three-cylinder. Whether set in Comfort mode or Sport+ of Driving Dynamics Control, all went well, even when we hammered it to the 7,000-rpm redline and yawed our way around the mighty plastic cones. But then in normal loping mode, everything was pretty unremarkably fine as well – and that's not a criticism.

Can we embrace this three-cylinder turbo in a BMW? Yes. Does it feel cheap and are we just pandering to a BMW bias? No. This is a legitimate and significant move that's long been in the planning stages, not a fluke. It'll be put to use in every model below the 5 Series, we are told.

Catch the rest of the article and some technical discussions on the B38 at Autoblog.

[shivaswrath]

interesting offering...