BMW Considering Two-Cylinder Engines?
Dr. Klaus Draeger is the man in charge of development at BMW. We’re filing this under rumor for now, but in a recent interview with the German magazine Auto, Motor und Sport he eluded to the possibility of two-cylinder engines in small BMWs and even future MINIs. First the what, then the why. According to Dr. Draeger, the sweet spot for a small power plant of this type would be about 500cc per cylinder with a target horsepower of 80-100 hp. That’s not a particularly tall order given what BMW can do with motorcycles. For example, a BMW F 800 ST sport touring bike is squeezing 85 reliable horsepower out of just .798 liters of opposed twin. At the other end of the performance spectrum, the .999 liter BMW S 1000 RR four-cylinder is blasting an amazing 193 hp.
So an efficient but powerful twin is the engineering equivalent of low-hanging fruit for BMW, but why go there? The answer is actually a pretty simple relationship: cost vs. fuel efficiency. More specifically, in small vehicles the cost and complexity of hybrid systems doesn’t tend to provide the kind of high-percentage mpg gains they do in larger vehicles. So for a small car like the MINI, or even the upcoming FWD offerings from BMW, it makes sense to look for extra mpgs by reducing displacement (and even cylinders) rather than adding hybrid drive systems.
Where would these engines fit in, if BMW pursues them? Chances are they’d be reserved for the smallest of BMW’s and MINI’s offerings. As we’ve reported previously on Motoringfile, MINI is already testing a three-cylinder engine for the next generation MINI Cooper S hatch — a car that will share platform with FWD offerings under the BMW propeller. Could we see a two cylinder Cooper or One? Only time will tell.
What do you think? Does the number of cylinders under your bonnet matter to you so long as the horsepower is there? What if the trade-off is impressive yet simple gains in efficiency? We know you have an opinion.
<p>my only concern with switching to motorcycle engines is the accompanying motorcycle sounds / power curves. it would seem that most of the time the power comes high in the rpm range and is paired with a high-pitched whine.</p>
<p>Could see this in a mega city car development. Not much interest to me. Three cylinders are hard enough to conceptualize let alone two heh.</p>
<p>In 1970 I owned a Honda 600 Sedan as a second car for commuting. It was pretty peppy for a 600cc motorcycle engine as a power plant and the fuel mileage was very good. I liked it so much I took it on freeway long distance trips and I even made a bracket to tow my motorcycle (which had more HP than the car) and it did that very well. With today’s technology I see no reason that BMW could not do a great job with the idea.</p>
<p>I agree StephenS, if any company could do a good job with this BMW would be my best option. Still the more than a little weight gain between a Honda 600 and a R56 is more than a little.</p>
<p>Hardingsan,</p>
<p>Just because it’s a two or three cylinder mill, that doesn’t make it a motorcycle engine. The moto motors are simply a good example of what kind of power can be made from less displacement. As for power curves and sound, that’s all adjustable. Not all motorcycles are loud and many are tuned for very broad power bands including lots of available low-end torque.</p>
<p>nathaniel,</p>
<p>sorry for leaping to conclusions. when i read the article it looked like dr. draeger was the one inferring motorcycle-ish engines are the future. cylinder count doesn’t mean too much to me, as long as it has the performance to back it up. i would just request that my mini drives like a screamer without sounding like one.</p>
<p>I definitely can’t argue with you there, hardingsan. I wouldn’t want my car sounding like a crotch rocket either. Mufflers are a good thing!</p>
<p>I like most people plan to by a bigger and more powerful car with each successive new car purchase…two cylinders may be a fine option for some but not for me.</p>
<p>dr,</p>
<p>Really? Why is that? Doesn’t that quickly push you away from MINI all together?</p>
<p>It is known that BMW 6-cylinder engines are turbine smooth. When you get to 4-cylinder engines they tend to be less smooth.
What will a 2 or 3-cylinder engine drive like? will it be smooth? will it perform like a 4-cylinder?
If we are trying to replicate 4 or 6-cylinder performance and values, why go to a 2 or 3-cylinder engine? It seems that engineers could squeeze more efficiency out of newer 4-cylinder engines.
A gallon of gas has only so many BTUs of heat (energy) – does it matter also if a fewer number of cylinders are used – I am an economist, not an engineer.</p>
<p>as long as there’s still a turbo option on the S 😛 though i’d have to admit… a potential of an opposed twin engine REALLY intrigues me… maybe a Honda high rev engine competitor is in the works in this idea! even it its not intentional!</p>
<p>Michael,</p>
<p>It’s more about displacement than number of cylinders in the end. Honda made a CB350 four-cylinder back in the day, so it isn’t as though you <em>can’t</em> build a small engine with many cylinders. Reducing the number of cylinders simply reduces the complexity of the motor when what you’re really trying to do is do more with smaller explosions. As for smoothness, yes there is a broad relationship between smoothness and number of cylinders, but I’ve ridden some mighty smooth two-cylinder motorcycles, so it isn’t as though it can’t be done. A two or even three-cylinder engine would be nice and torquey for it’s size, so that’s a plus.</p>
<p>Again, keep in mind folks that this is just a rumor at this point. No cage wheels have been purchased. No hamsters have been bred.</p>
<p>The next generation of BMW engines will be based on a modular design using a standard 500cc capacity per cylinder to simplify cost and construction, so 2cyl 1.0ltr, 3cyl 1.5ltr, 4cyl 2.0ltr, 6cyl 3.0ltr and V8cyl 4.0ltr.
The twin cylinder engine would be ideal for the Minissimo City Car.</p>
<p>I used to drive a 2 banger Honda 600 car as well. It was a nice little car, air cooled engine and all.</p>
<p>I’d drive something like that again!! I loved it.</p>
<p>“Does the number of cylinders under your bonnet matter to you so long as the horsepower is there?”</p>
<p>No, it does not. Build me a car that is light enough for a 2-cylinder engine to power it in a relatively spirited manner and I would put it on my shopping list.</p>
<p>@StephenS and Nathaniel (you beat me to it).</p>
<p>Yes, the Honda Scamp (N360) had a 354cc motorcycle engine in the 1970s. see <a href="http://en.wikipedia.org/wiki/Honda_N360" rel="nofollow ugc">http://en.wikipedia.org/wiki/Honda_N360</a>
I think I drove one once and they sounded like a motorbike. They did rev higher than the BMC Mini 848cc engines of the time but went very well. They came as an auto as well.</p>
<p>Don’t forget that the original Isetta was 1 cyl 249cc engined bubble car. So its not as if this is new to BMW. <a href="http://en.wikipedia.org/wiki/Isetta" rel="nofollow ugc">http://en.wikipedia.org/wiki/Isetta</a></p>
<p>I think it will be a 2 cylinder more like the Fiat 500 Twinair, it’s a 900 cc 2 cylinder with turbo 85 hp, and they are planning to do a 100 hp or something like that, and torque is same than 1.4 liter.</p>
<p>Traditionally, the mechanical quality of a vehicle has been related to the number of cylinders: a higher quality more cylinders, and this is an unalterable truth for physical reasons. It is true that BMW is capable of producing reliable 2 cylinder cars at lower cost, but if I had to choose I have it clear.</p>
<p>No issues whatsoever. I look forward to the upcoming news about the new engines.</p>
<p>I care most about mileage and style (the kind of buyer that the racing MINI people hate). I live that my Clubman can approach 50 MPG (48.9) when I hypermile on the highway for a couple hundred miles. If I can cross that 50 MPG threshold I’d be thrilled. I don’t care how many cylinders are required to accomplish the goal. I have to think there are other people like me.</p>
<blockquote>dr,Really? Why is that? Doesn’t that quickly push you away from MINI all together?</blockquote>
<p>Yes and no….I don’t mean that one goes straight from a MINI to a full size sedan or suv…but the r56 is bigger than the r53 and the r60 bigger than both, rest assured that the next gen mini will be bigger still….models bloat with each successive year and they do so for a real reason. People want/ need more! When I am ready to give up my R53 I want more space and more power than I had before…..otherwise, the chances are high that the small car does not get my dollar. This is in large part why the R60 exists, because while an R53 was the perfect car when I was young and single, its less so when I marry a woman who has no desire to shift gears manually, have children whose child seats barely fit and get a dog that doesn’t fit in the tiny trunk with the kid in the backseat…..it’s one or the other, kid or dog….hmmm which do I take to the park today?. Does a 2 cylinder “city car†make sense to a young single hipster who can walk/ride anywhere anyway in the dense urban metro….um, sure, maybe….maybe 15yrs from now, every kids first car will be a 2cyl golf cart like thing…..but for me 15yrs from now, I will be hauling teenagers to soccer games and going to the doctor for the joint pain caused from the sport suspension in my R53….I’m exaggerating a bit here, but only to make the point that most people need more space and more comfort as they age and life changes…..So until the kids leave, I retire and I then need a little tow behind for the RV I will not be in the market for lesser car….and that is just me. Throw in the climbing income, career and lifestyle factors which come with age and influence most other peoples car buying decisions… Why buy less of a car when you can easily afford more? I mean lets face it, that’s why we bought a premium brand rather than a kia……What you have, IMO, is very few people who will buy a small and adequate car when they have had more before….What you have is a C-car that becomes very entry level product and for most people is their first car…..I am confident that won’t be my next car….and while I really like the R60 for our next car, I’m not sure that MINI can continue to meet our needs our family grows.</p>
<p>I would be open to this approach in principal, and would be very pleased to see MINI get back to thinking smaller, for a change.</p>
<p>One grammatical nit pick point. Second line: I believe you meant to write ‘alluded’, not ‘eluded’.</p>
<p>Sounds good to me. If we all must go small in the future I’d rather do it in a MINI.</p>
<p>Related to displacement, I used to own a 900cc Subaru wagon (anybody else?) that had room under the hood for the spare tire WITH the engine! That would be a change from the current MCS, eh?</p>
<p>Smoothness is also a function of balance in the engine design.</p>
<p>R53 to R56 does not represent any growth. You are back to the tired styling gripe. Sorry – weak reasoning/rationalizing going on in the foundation of your argument.</p>
<p>It will be interesting reading the opinions on a two cylinder engine when the price of gasoline goes over $4.00 a gallon. History usually repeats itself.</p>
<p>Sorry…when you talk two-cylinder talk, I just can’t get the sound of an old John Deere tractor out of my head…</p>
<p>Dr,</p>
<p>I understand the premise of the next car will be more, but I think that is up to a point. In a handful of years, I’ll retire and move closer to family. No kids, no chauffer duties, no need for long driving trips to see family, and I can see going smaller. Where will I go, to the grocery store, out to eat, etc.</p>
<p>I defnitely plan on staying small, even down scaling. My current plan is a no option R60 MC, although I could see myself in something like a fiat 500. At some point in your life, bigger and better, particularly on a retirement income isn’t always better.</p>
<p>BMW F 800 ST has a parallel twin engine – not an opposed boxer twin cylinder engine. I believe it has a counter balancer to smooth it out.</p>
<p>The F800ST is actually a parallel twin, not an opposed twin.
In BMW motorcycles, the current naming convention:
G – single
F – parallel twin
R – opposed twin
K – inline 4 or inline 6
S – inline 4</p>