Quote:
Originally Posted by lovec1990
it does say it,but for example starter is ten times stronger too withstand ASS operation
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My friend, I'm not sure where you're getting your facts from - can you please reference where you've learned that the starter is "ten times stronger" to withstand auto stop/start operation? And ten times stronger than what? A conventional starter? A previous BMW starter pre-ASS?
As Grover pointed out, the manual clearly states that ASS operation WILL prematurely wear engine components (I have a US car and manual). They don't simply call out the starter, by the way, which I believe is probably just one mechanism taking the brunt of the constant starting/stopping of the engine.
I'm not a mechanical engineer, but I've taken enough engineering classes to know that moving parts, when constantly stopped and started, and friction is in play, will get worn. The engine, and all of its many components, are continually being asked to go from a steady-state (running) to a stopped-state and back again. Maybe someone who's more mechanically inclined than me can provide a reasonable defense of the technology, but simple physics would seem to suggest that it can't be beneficial as far as wear-and-tear.
So, the real question is Return on Investment (ROI). Any first year college student in a business program learns the term... a simple concept: what reward do you reap for your investment? In the case of ASS, each owner is paying $X in the purchase price of their car to have this technology present. Each owner is also experiencing additional engine wear that reduces the lifetime of certain components to the tune of $Y in additional maintenance. This is all done in the name of saving $Z in fuel costs. So the ROI question begs... is $X + $Y < $Z? I'd love to know.
I have a feeling (and it's only a feeling as I haven't done the math) that the answer is no. Sitting at a stop light, given how brief a time and how little strain is put on the engine, eats up a minimal amount of fuel. How many hundreds of stop lights does it take before ASS saves the owner even a gallon of fuel? Here in the US that's about $4.50 for premium (my neck of the woods at least). How many THOUSANDS upon thousands of stoplight stop/starts does it take to save me a few hundred dollars in fuel? Effectively, I've now taxed the engine (starter and all other relevant components) the equivalent of years worth of additional daily "normal" starts to get to this point? Again, all anecdotal, and I haven't done any real math here... but I have a feeling the economics just aren't there.
Seems like a gimmick and more trouble than it's worth... which is why I keep it OFF.