</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (White240sx @ Mar. 08 2002,5:48)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (XylathaneGTR @ Mar. 07 2002,5:57)</td></tr><tr><td id="QUOTE">BMW came out with a new one called Valvetronic or something...and it's suppsoed to be freaking amazing...</td></tr></table><span id='postcolor'>
Are you talking about what's in the New 7 series? It's so advanced; it negates the use of a throttle body. It uses valve lift to control the engine speed, by implementing an intermediate arm, whose pivot point can be altered to affect the lift of the valve. The double VANOS system is also a part of Valvetronic. It's projected that this technology will be available in the entire line in a few short years, which gives engine tuners something to look forward to.</td></tr></table><span id='postcolor'>
one sec, lemmie grab the mag i saw it in
In February 2002, Volume 14 no. 2 of Sport Compact Car...Page 14, in the TechnoBabble colum
It says,
BMW's new valvetronic is the first production variable valve timing system capable of delivering infinitely variable lift and timing, an accomplishment with far reaching effects thruought the engine.
Valvetronic is a confusing grab of rockerarms, roller followers, springs, eccentrics, anc cam lobes. Most of these parts just get in the way of understanding how it works...Valvetronic uses a conventional cam lobe and a conventional rocker arm, but between them is an intermediat arm. The cam pushes sideways on the midle of the intermediate arm, and the intermediat arm, pushes on the conventional rocker arm...
The foot of the intermediate arm, the part actually pushing on the rocker arm, has 2 parts. the lazy part, is preciesely contoured to slide along the rockerarms roller follower without actually pushing on it...the hard working side of the foot, is shaped to actually open the valve.
The magic part is...The intermediate arms pivot point can be moved back and forth, which changes which side of the intermediate arm's foot gets used. When full lift is needed, the piviot point moves to the right. This makes the hard working side of the foot, allowing up to 9.1mm of valve lift. When less valve lift is needed, the piviot point moves left, letting the lazy side of the foot roll around uselessly on the rocker arm. Only as the very tip of the cam lobe reachs the intermediat arm's roller does the valve finally pop open ever so briefly. When the pivot moved all the way to the left, the valve never opens at all.
Whew...thats the main part of the article...the diagrams would be usefull <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>
BMW is working to incorporate it in all its production engines, the first, the 1.8 Liter four in the 316ti, went into production in June 2001. The first valvetronic engines to appear in the US will be in the new 7 series, and an entire valvetronic equiped line will be avalible in a few years.
So yes...Your right.