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New boxer engine (VVT) 2018?

Discussion in 'R1200RS Tech and Performance Chat' started by Mans Ulvestahl, Jul 29, 2017.

  1. Mans Ulvestahl

    Mans Ulvestahl Member

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  2. James Bagley

    James Bagley Well-Known Member

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    My last BMW prior to my '16 RS was a '60 R60 (28PS). I still haven't readjusted my paradigm to 125hp...
     
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  3. Mans Ulvestahl

    Mans Ulvestahl Member

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    Are you still in first gear? :D
     
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  4. DJBee

    DJBee Active Member

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  5. runnerhiker

    runnerhiker Well-Known Member Contributor

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  6. Aussie Import

    Aussie Import Well-Known Member

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    The original telelever did not use the same structure, and it worked, without issues. I guess the newer design saved BMW a little me in manufacturing.
     
  7. DJBee

    DJBee Active Member

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    Honda's version of variable valve timing (it is not actually VVT at all but that is another story) ruined their beautiful VFR engine and stopped me from buying one at least twice. It made the engine peaky and very expensive/difficult to service. It achieved no advantages at all that I could detect and I still think of it as a great crime against wonderful engineering design. I still have my original 750VFR, non-VVT version. It remains a wonderful engine. I have also driven VVT Honda cars and deeply disliked their violently peaky torque curve.

    Most people agree that the 1200cc LC Boxer engine is very good in most respects, powerful enough, economical (I am getting 60mpg out of mine!), reliable and with a decent spread of power. Why make it unnecessarily complex and expensive to look after by attaching a gimmick to it, as Honda did to the VFR engine ? If it ain't broke, don't fix it!
     
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  8. Aussie Import

    Aussie Import Well-Known Member

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    I have looked at the Fiat "MultiAir" approach. It turns out that the big mover and shaker (apart from Chrysler-Fiat) is Koenigsegg, the sports car maker that was to buy SAAB when it folded. His technology is called "Free Valve".
    The motor does not have a cam shaft. Each valve is operated by electronic solenoid, and the timing of its opening and closing, and the total lift, is all programmable. It is programmable to the point where you can have a motor with little valve lift and no overlap at low speed. You can program it so only 1 inlet valve operates, and only 1 exhaust operates, to create more "swirl" and more efficient operation at low speed.
    Unlike the Honda VFR, and several others, where the "VVT" does not actually vary the valves that much. Generally VVT permits the "rockers" or other valve train items to slide from one cam lobe to another, there being 2 lobes side by side. Other systems actually change the timing of the cam by advancing or retarding the cam shaft compared to the crank, but does not change its lift or duration.
    None of the current "Free Valve" news items suggest it is being used for high performance, it is more to do with lower fuel consumption and emissions, recognising that so many cars operate in heavy traffic.
    What it does indicate is that VVT systems, like Honda's, are unlikely to be the long term solution if the machinery for the "Free Valve" is reliable and able to operate at high speed.
     
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  9. DJBee

    DJBee Active Member

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    Now that sounds interesting. This could be a virtually infinitely adjustable valve timing system that could be tied in to engine mapping, demand, gas flow etc. It sounds very complex as well and one has to wonder how solenoids would fare at the temperatures found right above the combustion chamber. Presumably they would use some form of wireless communication rather than physical wiring?
     
  10. Aussie Import

    Aussie Import Well-Known Member

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    It has been working for Fiat and it uses wires.
     
  11. Richard230

    Richard230 Well-Known Member Contributor

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    The latest 2018 Suzuki 1000cc sport models use VVT. They have some sort of sliding ball bearings on the ends of their camshafts that go up and down depending upon the camshaft speed, which affects valve timing in some way. :confused: Recent dyno tests seem to show an increase in low/medium speed power and just average top-end power, and a little less peak rpm, compared with their rivals. All of these new engine designs seem to have plus and minuses - especially when they are being used to meet new government clean-air emission regulations. o_O
     
  12. shorn sheep

    shorn sheep Active Member

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    I'm with you about the v-tec on the VFR800, I had a VF500 in the 80's and a vf750 a bit later on. The 500 was a fantastic engine with such a nice power spread, but fast forward to the 2000's I bought an 800 with the vicious vtec. I grew to hate the on/off power boost that kicked in at a certain revs like a switch being flicked, it's not what you want on a bike. Honda obviously missed out when the concept of 'Linear' was being handed out. And look at what a disastrous flop the 1200 turned out to be despite all it's technology, 'character' is another word missing from their vocabulary
     
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  13. Richard230

    Richard230 Well-Known Member Contributor

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  14. Vtbob

    Vtbob Well-Known Member

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    VVT is far from new technology...evan for BMW. I have it on my old 2001 Z3 3.0L engine. Almost all new cars have some version of this.
    What it does for that engine is broaden or narrow the duration of the valve openings. At lower RPM the valve timing is more like a farm tractor...ie little over lap..so the engine is very torquey at low revs...give great gas milage ( no overlap so no fresh gas goes out the exhaust valve)...then at higher RPM the valve open duration in increased and at high rpms there is substantial overlap..ie intake valve is open when the exhaust valve is open...this insure a full charge of fresh gas in th cylinder but puts unburnt fuel out the exhaust too...EPA does not like that)...but does give a noticeable increase in HP at high RPMs.
    With out variable valve timing the engine is set up for a compromise ...good low speed response and torque at the expense of high peak HP.
    With VVT you get the best (or better) of both worlds
    For the best of me, I can not think why VVT would make a engine run worse!!

    Good Idea BMW motored...and about time! ps the S1000R has vvt
     
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  15. Richard230

    Richard230 Well-Known Member Contributor

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    My guess is the the upcoming Euro 5 regulations spurred BMW into using VVT technology in their new engine. Reducing valve overlap is good for emissions in the rpm range where the engine is used most of the time and likely where emissions are typically measured. Then increasing valve overlap will allow them to maintain peak power claims and top speed.
     
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  16. OW31

    OW31 Member

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    Since when?
     
  17. Richard230

    Richard230 Well-Known Member Contributor

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    That would be news to me, also. If the S1000R/RR has VVT, I have never heard about it. :confused:
     
  18. Vtbob

    Vtbob Well-Known Member

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  19. ray2

    ray2 Well-Known Member Contributor

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    True enough - variable fuel pressure and variable intake manifold length - but not valve timing (this month). (http://www.webbikeworld.com/BMW-motorcycles/bmw-s-1000-rr/s-1000-rr-motorcycle-2.htm)

    Must have been a special. Not sure the weight of the Vanos makes sense on the RR.
    (And then there was a recall on a bunch of BMW cars when the VVT units loosened up - just one more thing to go wrong.)
     
  20. Aussie Import

    Aussie Import Well-Known Member

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    Just to beat the old drum, don't think of VVT, think of the potential of the "Free Valve" or "Multi Air". For the bikes that use the inline 4's, the elimination of the cam shaft means they can be made like a VW "V-6", with the cylinders off-set, say, 15 degrees between 1 and 2, and 3 and 4, allowing the overall width to be much slimmer, still using the 1 cylinder head.
    The "Free Valve" could also adjust compression (closing the inlet valve early), provide more torque through turbulence (opening one set of valves diagonally). Improve economy (no valve overlap), increase the speed of the valve opening and its travel, or smooth it out with less "lift". All this can be done according to a computer which monitors throttle position, rpm, gear, speed, cornering attitude.
    As far as "race tuning" is concerned, all items that are normally touched or require metal work are largely eliminated. No "race cam", no real need for greater inlet volume, no messing around with compression. All fuelling can be done with the computer.
    You can make the motor a "slogger" that would find a happy home in an Indian field pumping water; or a screamer for a track day. You can provide a wave of torque that is infinitely adjustable with all troughs and peaks smoothed out.
    It may even be more compact than a double overhead cam head, with or without VVT hardware.
    As far as the VVT making an engine peaky, some people like that. As a kid, I liked the way my Yamaha 350 "came on the pipes". I liked the "whaaa, whaaa, whaaa, wingggg" feeling when the ports, and expansion chambers matched up.
    I was bored by the "steady as she goes" Honda 350, that did not have the life and the sparkle.
    Oh well, what do kid's know? Now a big torquey twin is just fine.
     
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