New VVT boxer engine
- Thread starter team duvet
- Start date
1250 cc
Good 
Thanks for posting.
VVT has speculated to be coming on the second generation LC since it was introduced, a main benefit of the LC cylinders being turned, and it appears it's finally coming. It should offer KTM chasing power while still producing the low rpm grunt we love.
VVT has speculated to be coming on the second generation LC since it was introduced, a main benefit of the LC cylinders being turned, and it appears it's finally coming. It should offer KTM chasing power while still producing the low rpm grunt we love.
Here's hoping that 95% of the issues following the redesign will have been sorted when I upgrade in 2 years time
Deleted account 190920001
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Here's hoping that 95% of the issues following the redesign will have been sorted when I upgrade in 6 years time
Fixed it for ya
patzx12
Registered user
He is a big lad.
Indeed.
Think I'll keep my head down and enjoy my Fork Failing Anxiety Afflicted Rust Racing Torque Tractor for a bit longer before I pay £20k to join the new BMW Beta Testing program.
Can't afford the Councelling Fee's.
Think I'll keep my head down and enjoy my Fork Failing Anxiety Afflicted Rust Racing Torque Tractor for a bit longer before I pay £20k to join the new BMW Beta Testing program.
Can't afford the Councelling Fee's.
Here's hoping that 95% of the issues following the redesign will have been sorted when I upgrade in 2 years time
Yes...... hopefully.
Of concern to me are the likely added weight and bulk as well as added complexity. These engines already make enough racket with all the clattering and whirling noises, hopefully this doesn't add any more. Have to like the thought of both more HP and low end torque though.
I hear ya, but wouldn't we be onto the mark 7 (EV) version by then?
VVT on a bike: brilliant idea, but as much use as tits on a boar pig on a road bike. Kick up the butt acceleration as you hit the appropriate rev band - not really ideal when applying power out of a bend or corner. VFR vtec pilots will know the feeling, I'm sure. I like smooth, predictable power delivery on a bike (a bit like the pre vtec VFR... or the GS) although YMMV and I'm happy to be considered a heretic.
I'd be surprised if they repeat Honda's "mistake". BMW have a lot of knowledge of both variable timing and valve lift, to the extent (so I read) some engines don't have throttle valves - just vary the lift to meter the air going in. Valvetronic is the variable lift system. There is a throttle valve, but it's kept wide open in normal operation. Bit like my GS, then. ;-)
Different manufactures have different names for a similar thing. Honda call it vtec, Mitsubishi mivec, etc.
That's true. I have had a couple of 3.0ltr M54 engines with dual VANOS which delivered power without the 'kick' the two examples above certainly did deliver. There must be an inertia/momentum thing involved though - any "kick" is sure to be less noticeable in a heavy car than on a much lighter bike with a higher power:weight ratio.
VANOS is the variable valve timing; Valvetronic is the variable valve lift, done with a stepper motor and an intermediate camshaft. I've been watching YouTube, tha' knows.
My understanding is VTEC engines incorporate 4 valves but normally operate with only two until a certain rpm when the other two are suddenly enabled. My Honda S2000 used this and as with VFR's it was quite noticeable when it kicked in. None of my current vehicles which have VVT have such an abruptness.
fred_jb
Registered user
VVT (Variable valve timing) is different to VTEC. VTEC just brings into play an additional pair of valves per cylinder at higher rpm, where 4 valves is the optimal configuration, while allowing the engine to run in 2 valve mode the rest of the time as this is optimal for lower rpm.
VVT uses a variety of mechanisms to actually change the timing of valve opening and closing depending on rpm so as to get the optimum for different engine speeds. A particularly elegant system is that developed by Suzuki to get around the racing rules which don't permit electronic/hydraulic methods of altering valve timing. This uses ball bearings running in curved grooves in the drive to the camshaft. These get flung outwards as the camshaft rotational speed increases, and in the process change the position of the camshaft relative to the gear wheel that rotates it.
The idea of VVT is that you get optimal power production at all revs, so the comments about it only kicking in at a particular rev band are not correct, though that is how VTEC feels, albeit more recent versions have a less abrupt transition.
Excellent video here: https://www.youtube.com/watch?v=zbWEUVAQfZ0
Fred
VVT uses a variety of mechanisms to actually change the timing of valve opening and closing depending on rpm so as to get the optimum for different engine speeds. A particularly elegant system is that developed by Suzuki to get around the racing rules which don't permit electronic/hydraulic methods of altering valve timing. This uses ball bearings running in curved grooves in the drive to the camshaft. These get flung outwards as the camshaft rotational speed increases, and in the process change the position of the camshaft relative to the gear wheel that rotates it.
The idea of VVT is that you get optimal power production at all revs, so the comments about it only kicking in at a particular rev band are not correct, though that is how VTEC feels, albeit more recent versions have a less abrupt transition.
Excellent video here: https://www.youtube.com/watch?v=zbWEUVAQfZ0
Fred
fred_jb
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I believe that is how the Fiat TwinAir engines operate. My wife has the 900cc twin in her Fiat 500 and it is quite strange to drive as it seems to have no power curve and no tailing off at higher revs to give you a cue to change up a gear. Consequently I'm always hitting the rev limiter (at about 5000 rpm) in first, and often find myself driving along at about 60 still in third until I notice the little change gear indicator on the dash.
Deleted account 181015003
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The Kawasaki 1400GTR has a VVT version of the ZZR1400 engine and is very smooth with loads of power from very low down without a sudden VFR type surge in power I am sure BMW will get the power delivery right first time the build quality is another issue
Whoo Hoo more complex shit to go wrong when yet again BMW use the public to properly road test their latest creations after it has gone on sale.
Well at least it means that dealers will have loads of low mieage triple black and Rallye bikes for sale when it does come out and no doubt some will already be down at the dealers attempting to place a deposit on the new R1250GS VVT triple black rallye
Well at least it means that dealers will have loads of low mieage triple black and Rallye bikes for sale when it does come out and no doubt some will already be down at the dealers attempting to place a deposit on the new R1250GS VVT triple black rallye
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