Join Date: Jun 2013
Location: New Castle, DE, United States
Re: ?? Variable Valves are Bad for the BMW R1250GS - Review ??
He does a good job of explaining why overlap should change as speed increases. He even illustrates that changing overlap (duration) means changing the cam profile. Then he goes on to diss BMW's choice of having two separate profiles and implies Suzuki's solution is better, even though it only changes valve timing. What?
Cam profile controls timing (when it opens), duration (how long it's open), and lift (how far it's open). Two cams on the same shaft can have two profiles optimized for two different speed regimes. Is it as good as optimizing for every possible combination of speed and load? No, but doing that would require doing away with a camshaft altogether in favor of direct computer control of the valve actuators. Imagine the grief BMW would get from the "I'd rather have mechanical <xxx> than computer controlled <xxx>" crowd if they did that!
2020 R1250 GSAW Low
2016 R1200 GSAW Low (traded)
2015 R1200 RT (traded)
2012 K1600 GTL (traded)
2012 R1200 RT (totaled, RIP)
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