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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.

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[Bradbury]

1.5L, 3 cylinders, 175 hp. Put two of these together and you have the 1M.

[r3dbimmer89]

B68 Inline six sounds promising...

Here's the link to Paul Tan's blog where he was at the same event and stated peak HP and TQ would be around 400 HP and 500 TQ for the B68 Inline Six

http://paultan.org/2012/10/01/bmws-b...in-a-1-series/

[AndyGF]

Engineers on hand wouldn't go into exactly what has been done with the manifold or pipes

That is because the engineers know the answer lies not under the bonnet/hood, but in the boot/trunk... I hope I am wrong but it wouldn't surprise me.

[e92miami]

Great, now make a nice car under 2800lbs or less then maybe you can use this little motor.

[logiclee]

According to BMW it doesn't have a twin scroll Turbo, hard to balance that up with three cylinders.

Cheers
Lee

[seis-speed]

Cool idea, but nothing I would buy. Efficient yes, exhilarating no, what happened to being the ultimate driving machine?

[Mahzari]

Originally Posted by seis-speed

Cool idea, but nothing I would buy. Efficient yes, exhilarating no, what happened to being the ultimate driving machine?

In order to make your "ultimate driving machine" BMW has to sell 100 1-series with 4-cylinder diesels. BMW is not Lotus; they do not make 1 line of high performance vehicles. This engine means the next M3 can have a beast of an engine because the CAFE regulations apply to the company's fleet as a whole.

Enthusiasts should be happy, even if they'll never drive a 3-cylinder BMW.

[bavarian19]

The reason why it sounds so good is probably because they took the synthesized sound of the M5 and plopped in into this car.

[Rich@GTBPerformance]

Originally Posted by bavarian19

The reason why it sounds so good is probably because they took the synthesized sound of the M5 and plopped in into this car.

[Whostheboss]

Originally Posted by bavarian19

The reason why it sounds so good is probably because they took the synthesized sound of the M5 and plopped in into this car.

[red-sauerkraut]

Originally Posted by bavarian19

The reason why it sounds so good is probably because they took the synthesized sound of the M5 and plopped in into this car.

You know they did just that.

I bet this little squirt of a engine will make 200hp w/ those balance shafts removed.

Not a bad deal for a range extender.

[Diver]

Originally Posted by e92miami

Great, now make a nice car under 2800lbs or less then maybe you can use this little motor.

My sentiments, exactly. Put this in something the size of a Mini and watch out.

[kmarei]

Originally Posted by bavarian19

The reason why it sounds so good is probably because they took the synthesized sound of the M5 and plopped in into this car.

I don't think we're too far from having engine sound upgrades as a factory option

And the aftermarket will be selling us trunk mount subwoofers as the V8 package
So the next wave of chip upgrades is just getting bigger subwoofers, for a deeper engine note
Can't wait to hear the dinan sub, cuz it won't void my warranty

[red-sauerkraut]

Originally Posted by r3dbimmer89

B68 Inline six sounds promising...

Here's the link to Paul Tan's blog where he was at the same event and stated peak HP and TQ would be around 400 HP and 500 TQ for the B68 Inline Six

http://paultan.org/2012/10/01/bmws-b...in-a-1-series/

A great read - Thanks for sharing

[bimmerjph]

I bet this engine has a sound generator.

[dd1981]

Originally Posted by Bradbury

1.5L, 3 cylinders, 175 hp. Put two of these together and you have the 1M.

Thats alot of power out of 3 cylinders. I like it. It makes me think is the M2 going to be a 330-340 hp N20 variant? Lot of new and exciting stuff BMW is doing. Cant wait for the M2

[Teemo Panda]

Originally Posted by Bradbury

1.5L, 3 cylinders, 175 hp. Put two of these together and you have the 1M.

Lol, one engine in the front and at the back :P

[PostModernHero]

Originally Posted by bimmerjph

I bet this engine has a sound generator.

Just go ahead and post away without reading what anyone else said. Yep...

[leewoods18]

Originally Posted by PostModernHero

Just go ahead and post away without reading what anyone else said. Yep...

:

[ovekvam]

Thre cylinder engines have always had a special sound, not all unlike the six. I wouldn't mind owning one if it has the same or better throttle response than the current four.

[Ascari]

Originally Posted by Mahzari

In order to make your "ultimate driving machine" BMW has to sell 100 1-series with 4-cylinder diesels. BMW is not Lotus; they do not make 1 line of high performance vehicles. This engine means the next M3 can have a beast of an engine because the CAFE regulations apply to the company's fleet as a whole.

Enthusiasts should be happy, even if they'll never drive a 3-cylinder BMW.

Correct! If they only made the cars us enthusiasts like, well, they couldn't afford to make just those cars. More innovation, more efficiency, breaking down barriers is good for all of us and the best news is that you still get to choose what suits you from an ever expanding range.