Looks like Pitroad has the adjustable cam gears - kinda expensive though:
http://www.pitroad-ts.com/englishpage/a-02.htm

Oh, and they work with the 76mm bore engines.

I would also like to say:
"Bunnies!"

Not that I'm adding to the conversatin but I too have read of both of those innovations, BMW's throttleless system and Saab's variable compression.
The BMW thing basically varies the lift and timing on the valves to such a degree that it keeps the engine at the best volumetric efficiency for the given load and speed. They barely crack open at low speeds but really get wide when needed.
Saab's thing has the cylinders and crank seperatated, and a pivoting device that makes the pistons ride higher or lower in the cylinders to vary the compression. They, Saab, also were playing with a variable spark gap engine where the piston has a little "titty" in the center that acts like the ground electrode on the spark plug. I'm not sure what the reasoning behind that one was though.

Quote:No, but the in the new BMW 7 series the camshafts move up and down to control valve lift, and thus airflow. The engine doesn't even have a throttle!

SAAB has made the prototype, it will go in production in a couple of yrs, its supercharged which engages when boost is needed only, its block moves few degrees away or closer from crank to increase or decrease compression. compression ranges from 8.x:1 - 13:1(approx.) it basically combines power of a supercharged engine and economy of NA engine.
barpk

yeah i heard about it being on a saab to. I thought it would be a good idea wonder if it worked. By thery it would be excellent

Matdat

An year ago Saab (I think) presented a engine with variable compression. However, it wasn't the crankshaft that moved. Instead the engine head rotate (pivots) (!!!!strange system!!!!) for about 4 degrees.

Ricardo

Can't say that I have heard about it!
Have you or are you just asking if it is around?

its a bit off subject but has anyone heard about variable compression like moving the whole crankshaft up or down on a engine running boost so you still have down low power

You may be right. I thought the VTEC changed the camshaft phase. It seems like all the auto makers have a variable valve timing system now. Some vary lift, some timing, and some both.

For a single-cam cylinder the cam can't be advanced/retarded as much -- just a few degress. I heard that VTEC moved the intake something like 50 degrees!