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Originally Posted by bestclimb
The balance of the engine is engineered for all 8 jugs functioning, it may/will run rough. (this may or may not be an issue mechanical and would be up to you if it is a comfort/annoyance issue)
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I expect to feel some difference from the engine if 4 cylinders are deactivated. However, I don't think this is such a big issue from a mechanical longevity standpoint, as the Chrysler 5.7L MDS system shuts off the exact same cylinders as I had considered, and the only thing I have read about is that some drivers complain of a low vibration between 1100 and 1800 RPMs when MDS is engaged.
Quote:
Originally Posted by bestclimb
The biggest one efficient wise is that you are still accelerating and stopping and accelerating a bunch of mass in the pistons and the of scrapping the rings along the cylinders of the deactivated jugs several thousand times a second.
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It's called friction losses. Can't get around that.
However, it's not much of a concern. If the Big 3 can make variable displacement work on their production engines, and can get significant improvements in fuel economy, even with friction losses of the deactivated cylinders, then it's not much of a problem.
I think you meant to say "minutes" instead of "seconds," though. If my V8 were somehow able to make its pistons reciprocate thousands of times per second, I don't think it'd live for much longer than a few seconds.
Quote:
Originally Posted by bestclimb
Got anything against pulse and glide?
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It's unrealistic for a daily commute.