BMW shift-cam technology

[pglaves]

As I've posted elsewhere, my view is that if a safety feature exists, it has to become standard everywhere due to liability concerns.

Moto Guzzi had linked brakes before BMW ...

No other motorcycle that I am aware of used electrically pumped power brakes with minimal residual braking with electrical problems. This has nothing to do with linked brakes or ABS. Just the use of power brakes where no such thing was needed - as evidenced by the few number of years before BMW woke up and killed the dumb idea. Not everything BMW is as if it was perfected and ordained by the Creator. It is a company, with engineers and accountants that sometimes makes mistakes. Recalls, anybody?

 

[lkchris]

My 2012 R1200RT no longer has brakes that "whizz," but it still has a $2200 electric pressure regulator.
http://www.realoem.com/bmw/enUS/sho...26-BMW-R_1200_RT_10_0430,0440_&diagId=34_1814

Looks like Wetheads do as well
http://www.realoem.com/bmw/enUS/sho...-K52-BMW-R_1200_RT_0A03,_0A13_&diagId=34_2079

The system has been refined, not "killed" it appears.

 

[deilenberger]

My 2012 R1200RT no longer has brakes that "whizz," but it still has a $2200 electric pressure regulator.
http://www.realoem.com/bmw/enUS/sho...26-BMW-R_1200_RT_10_0430,0440_&diagId=34_1814

Looks like Wetheads do as well
http://www.realoem.com/bmw/enUS/sho...-K52-BMW-R_1200_RT_0A03,_0A13_&diagId=34_2079

The system has been refined, not "killed" it appears.

Kent,

Happily, after some teething problems with the early ones - the later one seems quite reliable. It should be since it's basically a variation on the ABS modulator used in automobiles. And if it does crap out - ModuleMasters will rebuild it and give you a 5 year warranty for a bit over $300. Where a need is seen, so is an opportunity..

 

[wbrownell9]

On BMW cars, variable valve lift and timing replaces throttle plates, thereby reducing pumping loss and improving fuel economy.

Is this a feature of the R1250?

No. That system is way more complicated. Levers and motors and whatnot to vary lift, and hydraulic actuators to vary timing. Plus turbocharging. This is just a normaly aspirated engine with 2 lobes on one camshaft, and the camshaft slides back and forth.

Interesting that the specific output of the fancy car engines is about 112 hp/liter depending on model, the current wethead is 106.8, and the shifthead is 107.6. Not all that much gain for the added complication.

 

[1957mpd]

My observation of current R1200s is that they are gutless below 4000 rpm. ... Bet that changes with variable valve timing.

It appears the R1200's max torque, reached around 6500, is hit between 4300 and 4400 RPM on the R1250. (This graphic was provided by another forum member.).

 

[lee]

It appears the R1200's max torque, reached around 6500, is hit between 4300 and 4400 RPM on the R1250.

The graph shows the R1250 hit max Torque at 6,250 RPM.

 

[Gillie Dog]

The graph shows the R1250 hit max Torque at 6,250 RPM.

I think he is saying the 125Nm max of the 1200 is reached much earlier on the 1250 on it's way to its max of 143Nm at 6250 rpm.

GD

 

[lee]

I think he is saying the 125Nm max of the 1200 is reached much earlier on the 1250 on it's way to its max of 143Nm at 6250 rpm.

GD

Thanks

 

[Wkoppa]

Cycle News Test of new R 1250 GS

Inside is a test of the new GS.

Cycle News is a free electronic publication - so sign up if you like what you see.


https://cyclenews.us2.list-manage.c...a23743ed849a5ee3f0&id=1370817e65&e=0e81d21325



Wayne Koppa
Grayling, MI
#71,449 Life

 

[ncpbmw1953]

Pretty cool. "Souvereign acceleration and impressive elasticity" now there's a catch phrase.

And don't forget 'Quantitative Easing' which refers to the new braking technology....

 

[AKsuited]

A video review of the new shift-cam GS:

<iframe width="940" height="529" src="https://www.youtube.com/embed/ogfMU0UXLls" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>

 

[1957mpd]

Great Vid

That answered all my questions. The big point, at about 4:30, "Is the R1250 a big enough step to make it worth making the jump off a R1200GS/GSA?", he answered - at least from their perspective. Thanks for loading this so soon.

 

[azgman]

Excellent review!

 

[vcheng]

That answered all my questions. The big point, at about 4:30, "Is the R1250 a big enough step to make it worth making the jump off a R1200GS/GSA?", he answered - at least from their perspective. Thanks for loading this so soon.

I want to wait for the Dual Shift Cam where the VVT is on both the intake and exhaust sides. This one is half-baked IMO.

 

[BC1100S]

I want to wait for the Dual Shift Cam where the VVT is on both the intake and exhaust sides. This one is half-baked IMO.

I think you might be waiting awhile. As well, this isn't so much VVT as its Variable Valve LIFT and I don't know many vehicles that have it on both intake and exhaust valves.

 

[vcheng]

I think you might be waiting awhile. As well, this isn't so much VVT as its Variable Valve LIFT and I don't know many vehicles that have it on both intake and exhaust valves.

I would still think that would be the next step technologically.

 

[Omega Man]

Seems like things are getting mo' complicatederrr

om

 

[ragtoplvr]

BMW is not the only sliding cam. Look at this

https://sandyblogs.com/techlink/?p=10221

GM is doing it too, and has cylinder deactivation too.

Rod

 

[oldcamper]

BMW is not the only sliding cam. Look at this

https://sandyblogs.com/techlink/?p=10221

GM is doing it too, and has cylinder deactivation too.

Rod

Washington Ironworks Diesel (tugboat engine) had it in 1934:

https://m.youtube.com/watch?v=ebvD1RnX7LY

... both intake and exhaust!

 

[wbrownell9]

I think you might be waiting awhile. As well, this isn't so much VVT as its Variable Valve LIFT and I don't know many vehicles that have it on both intake and exhaust valves.

They can grind whatever lift and timing profile they want on each of the four lobes per cylinder (2 low, 2 high). They already tell us that vary the timing between valves on the low speed lobes, one opens before the other. So there's no reason not to vary the whole shebang - timing, lift, and duration - between the two regimes.

BMW cars have infinitely variable timing and lift on the intake, and infinitely variable timing on the exhaust (not sure about lift).

I'm sure they did a cost/benefit analysis and figured that the best bang/buck was two cam profiles on the intake side. Doubling the cost & complexity for the exhaust side wasn't worth it. And frankly, you could explain the horsepower increase just on the displacement increase alone. So I'd argue that they did it to reduce emissions at low speed (Euro 5), as a side benefit got a little more torque at the low end, and decided that wasn't really enough to differentiate it so they took the opportunity to bump the displacement (it's been 1170 cc since 2005) because they have to have something to market and HP sells. I see they've changed to a "silent" chain to drive the cams, so maybe the engine doesn't make as much mechanical noise. That's a nice upgrade.