Say goodbye to the air-cooled BMW boxer engine . . .

[Grey Thumper]

"BMW is in the early stages of making an all-new, super-efficient, Euro4 compliant water-cooled replacement for its iconic Boxer engine.

The new engine is being developed because of tough Euro4 emissions which come in to force from 2012, and the current air-cooled engine doesn’t meet the new standards.

Air-cooling is a problem for engineers seeking lower emissions and reduced fuel consumption because efficiency is lost not just at higher engine temperatures, but also from cold.

By contrast, a liquid-cooled engine doesn’t get as hot when used hard, but also warms up faster because of the water-jacket’s insulation.

If you can control an engine’s running temperature and keep it within its ideal operating range, it can burn the fuel/air mix more cleanly and efficiently.

Insiders at the Munich development centre let slip to a specialist German BMW magazine that a top-secret project is underway to replace the air-cooled engine that can trace its ancestry back to the first boxer BMW bikes nearly 90 years ago with a new liquid-cooled replacement. "


http://www.motorcyclenews.com/MCN/News/ ... cooled-gs/

[Boxer]

It's about time. Maybe they can add some chrome too....and a comfy seat.

[Beemeridian]

1q2345t

[boxermania]

If BMW watercools the Boxer, reduce weight to 460-470 pounds, adds 15 hp, the vehicle design resembles the 2001-2005 R1150R and the price is reasonable they will sell a bunch......although it would be hard to compete with the F800ST.

[Grey Thumper]

If BMW watercools the Boxer, reduce weight to 460-470 pounds, adds 15 hp, the vehicle design resembles the 2001-2005 R1150R and the price is reasonable they will sell a bunch......although it would be hard to compete with the F800ST.

I've wondered why the F800R used chain drive, but I guess if it were belt drive like the ST, there would be little reason to get a 1200R (aside from "traditionalism".)

[CycleRob]

I agree with Boxer, it's about time!! Water cooling's advantages over air cooling are:
--Faster warm-up in any season.
--A thermostat model change can change the normal engine temperature.
--More HP easily obtained.
--Stable engine temps + tighter clearances = quieter engine.
--No overheating in stopped or slow moving traffic.
--Longer engine life.
--Higher fuel efficiency.
--No engine killing winter over-cooling.
--Copes well with a sustained full power setting.

Those are some very important advantages!

Water cooling disadvantages are:
--Slightly higher initial cost.
--Slightly increased servicing cost.
--Slightly increased weight.
--Often not as visually appealing.

Water cooling's clear cut advantages are the main reasons I upgraded to my F800ST instead of an R1200R. It was a smart move.

.

[Oilhead]

--Often not as visually appealing.

You are so right about that! I just love the way those oilhead jugs look with the cooling fins!

[tlwood28]

It has to happen. With the new Multistrada (and others) competing with the GS with 150 hp, BMW had to make the change. It couldn't possibly keep sales going with its oil cooled boxer which I suspect has reached its upper range in terms of HP. This story repeats what Porsche did 11 years ago with the 911. I will be very sorry to see it go.

[wncbmw]

I will also be sorry to see it go. With all the disadvantages listed, it's a wonder the old Airhead / Oilhead line lasted this long!

But I have heard this song before. I remember the twins were not to survive the introduction of the K-bikes in the mid-80s. We shall see.

But the time I am ready to replace mine, I will have to hunt a good used R1200R.

[Grey Thumper]

I'm game for water-cooling. I'm just wondering about the technical difficulties with designing a watercooled engine where the cylinders stick out so far horizontally. I'll bet BMW secretly wishes people had abandoned R bikes in favor of F and K engined bikes.

[Keppelj]

Functionally speaking, what's the point of the boxer design if air isn't the coolant? The jugs are out there for the cooler air. With water for coolant other twin designs become more efficient in terms of drag. OTOH BMW is not going to get rid of the boxer, its hallmark. Maybe some combination of water and air to warrant continued use of the design

[icemaker]

I think air cooled BMW's perfect machines and not need a water jacket.

[Buckster]

I think air cooled BMW's perfect machines and not need a water jacket.

I agree....they need to concentrate on building a better final drive and an upgraded clutch shaft!

[rutheugene2]

Writing as a professional product development Mechanical Engineer, BMW is in a real corner. The air / oil cooled design is doomed. Same for the Harley D V-twins except for their liquid cooled V-Rod. To control emissions, you have to have a much tighter control on head temperature, and that means liquid cooling. Only question is, how do they configure the cylinders? Opposed cylinders run relatively smoothly but they stick out too far - unless you just like that for nastalgic reasons. I don't think they would go to a Vee twin design. That market is already over crowded. I see them going to four cylinders. Perhaps a flat four with opposing cylinders, or a vee four like the Honda engine. That would make the design narrower. We will see. Don't see them dropping everything leaving only K bikes in the larger displacements. Marketing needs more options to sell.

[combatcarry]

I've been thinking about your comments on regulating engine temperatures... I'm an engineer also, but I'm Civil/Structural so I admit I'm not savvy on Mechanical Engineering (other than enough to become dangerous).

Why doesn't BMW simply regulate the oil temperature by thermostat in the oil cooler lines? On my old Harley Sportster I put an oil cooler and automatic thermostat allowing the oil to bypass the cooler until warmup. Admittedly the engine wouldn't warm up as fast as one insulated by a water jacket, but you should be able to regulate temperatures almost as well as water cooling by regulating the oil temperature. Harley has done this on their new "top of the line" Electra Glide so it might be their way of handling the problem (at least temporarily).

I'd hate to see air cooled engines die. I hope the engineers can figure out a way to save the old air-cooled boxer.

[rutheugene2]

Your comments are good ones. Actually, there are also other issues. Oil is not a good coolant because of it's very low specific heat. To get the same amount of BTUs transfered with oil, you have to blast very large volumes through the system. Then there are problems of having hot spots around the exhaust valves, of modern thin wall head castings, that slowly degrades the oil. Just isn't a good way to go. There are also efficiency issues of having relatively large cylinders. You can build a lighter engine, using more small displacement cylinders, with short stroke and low piston speeds to get the efficiency and power up. Not like the low rpm, high torque Boxer design, but everything is a trade off. If they kill the Boxer, there will be some very serious marketing questions of what to make next. They dare not get it wrong, and they already have a very good K design, so their options are limited. I would not want to be the one to make the decision. Too much riding on it, and too many unknowns, including the reaction of a fickle customer base.

One thing for sure, say goodbye to that antique dry clutch and hello to a modern wet clutch. About time.

I will keep my R bike, as I love the torque and lower rpm response.

[peterbulgar]

gray_thumper said: "I'll bet BMW secretly wishes people had abandoned R bikes in favor of F and K engined bikes."

I don't think that BMW was too secret about their wishes. I'm as much of a traditionalist as any BMW owner, but the world changes, and BMW has to change with it. They've done an amazing job of keeping the air/oil-cooled twins competitive, but I think they've exploited the design beyond what could reasonably be expected and it's time to go with water-cooling. I hope they stay with the boxer twin, although with water-cooling the only remaining advantages of the arrangement are a lower center of gravity and it's adaptability to shaft drive.
peter '73 R75/5, '04 R1150RA

[riceburner]

I'll bet BMW secretly wishes people had abandoned R bikes in favor of F and K engined bikes.

Don't you remember when the "Flying Bricks" came out??

They tried to stop making the old airhead boxers then - the "Mystic" (IIRC) was supposed to be the last of the line, a clearing of the old manufacturing stock. The tooling was getting old for starters!

They also made this decision public and there was a HUGE backlash from owners who loved the boxer engine and they were forced to reconsider. They kept making the airhead for a few years more while they developed the R259 (oilhead) series engines.

[riceburner]

Anyway - it's already been developed - noone remember this?

http://www.motorcyclespecs.co.za/model/ ... totype.htm


from here : http://www.bmwmoa.org/forum/showpost.ph ... stcount=33

[sweatmark]