MINI’s 3 Cylinder Engine Previewed

Last fall BMW trotted out a modified 1 Series hatch to a few select European journalists not to preview a car but an engine. Under the hood was the B38 3 Cylinder that will do duty in both rear wheel drive and front wheel drive applications for both the MINI and BMW brands.

Yes, this new 3 cylinder (codenamed either the N37 or B38 depending on who you talk to) will power the entire next generation MINI family starting with the F56 late this year (in both 1.2 and 1.5 variants). We’ve previewed it previously here on MF but one of our favorite automotive scribes Matt Davis has finally given us his impression on the engine. For anyone interested in the future of MINI (and BMW) small cars, it’s a must read. And it also allows us an opportunity ti update you on this new range of engines. .

Here’s a quick excerpt:

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.

The entire piece is well worth a read.

Now, about this engine. Matt previewed the engine known as the B38. This is the BMW version with a tune producing 170 hp. The sound and power delivery was designed to feel in-line with the BMW brand. We at MF have been assured that the MINI version will have it’s own tune with more of that spunky MINI spirit we’ve all come to love.

We believe that MINI intends on spreading the three cylinders across the MINI One and Cooper models initially with a very similar three cylinder diesel (reportedly code-named B37) joining the ranks. Sources are telling us that power ratings should be slightly higher than the current range on both the three and four cylinder models. But it’s the efficiency gains and the weight losses that are the big story. We’ve been told to not be surprised to see US Spec three cylinder Cooper achieve upper 40 mpg figures on the highway. Additionally the engines should be measurably lighter and allow for better weight distribution front to rear.

Ultimately we believe that the three cylinder engines will not only make their way to the hatch based models but also other MINIs as well. For instance don’t be surprised to see the base Cooper Countryman eventually get the ultra efficient power plant in a late cycle update.

Another update will be the packaging. In most markets MINI will be adding a hard plastic engine cover under the hood (or bonnet) designed to insulate the engine and make it cooler and more economically. How it works we don’t know but our sources were adamant that It could be a way for MINI to dress up the engine compartment while reducing noise and adding some level of efficiency.

What about the Cooper S and JCW models? We reported awhile back that those models will be staying with a four cylinder for the time being and we still hold to that. However instead of carrying over the Prince 1.6L engine we wouldn’t be surprised to see BMW’s new B48 four cylinder engines launch with the F56 as well. Those models will continue with the centered twin tailpipe design that has been a hallmark since 2001.

  • nick dawson

    Autocar drove the prototype 1-series with the 1.5 three cylinder engine fitted, back in October, and reported that the tiny three-pot engine, fitted in-line, looked lost in the engine bay. However, the short light engine mounted well back ensured that this experimental 1-series had an incredible weight distribution. Autocar found that lapping BMW’s mini circuit also showed another advantage of downsizing engines: the smaller, lighter internal parts make for a quicker-revving, more responsive engine., and with more of the weight in the middle of the car, this 1-series handled even more impressively than the four cylinder model.

  • b-

    I read this article and it looks promising for the MINI!

  • ulrichd

    I like what I am reading. Very interested in the 3-cyl Cooper as long as the exterior design is to my liking. Let’s hope there is some Rocketman DNA in it. Come on F56, shed some cladding.

  • Ray T

    “(in both 1.2 and 1.5 variants)” Is this correct? I thought each cylinder provided .5L

    • It was but we’ve now heard from two people that there will be a smaller version before they go to two cylinders.

  • Any further info on that B48 4-cylinder?

    • None yet but we’re digging.

    • Chilly

      I so hope this B48 4-cylinder proves to be true for the MCS. Can’t wait to hear more!

      Any idea when we’ll see photo’s of the F56 without the camouflage? The wait is getting too much! 🙂


  • Very nice! Can’t wait to test both the MINI and Ford three bangers. I see a future for larger aftermarket intercoolers. 😉

  • Don Hopings

    I don’t have a problem with 3 cylinders. For that matter, my first car, purchased new in 1972 was a 2 cylinder Honda 600 Coupe. However, the one thing that is a concern is for BMW to make sure the reliability is there. A 3 cylinder 1500cc JCW engine (when it gets here) will be a bit more highly stressed than the current 4 cylinder.

    • I’m highly encouraged by the huge amount of money BMW Group has invested in developing this engine system. Given that it’s going to persist across MINI and BMW, they have a vested interest in getting this right.

  • Bob Lavoie

    Like the previous writer Don H, I also had a new 1972 Honda 600 Sport Coupe with a 2 cylinder 600 cc aircooled motorcycle engine. But it only had 36HP to push the 1310 lb Honda to 60MPH in about 19 secs. Was about the size of a classic mini. Expect that 3 cylinder will do just fine in its expected usage. Will be awhile before I need another MINI. I currently still have my 2012 JCW Coupe…took delivery in its 1st month..Oct 2011…