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Old 12-27-2013, 01:27 AM   #17 (permalink)
Frank Lee
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Join Date: Jan 2008
Location: up north
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Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

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Quote:
Originally Posted by redpoint5 View Post
Great explanation Frank!

I wonder what extra precautions, if any, are required to make engines with cylinder deactivation reliable? With the same cylinders deactivating and shifting a higher load to the remaining ones, I would expect those to wear out faster. Is there any evidence of the active cylinders wearing out at faster rates than the others?
Thanks, I hope I got it all right; some aspects of it seem counter-intuitive, like why does the throttle need to open further when cylinders are shut down and the vehicle is only demanding the same power output.

I read somewhere- I think it was regarding the Honda deac system- that they don't expect any wear differences between dead and live cylinders. I find that suspicious at best, but maybe what they are really saying is whatever differences there may be are insignificant enough to ignore, and not make provision for alternating the cylinders' duty cycles. That could very well be as cylinder/piston/ring wear is not at all what it used to be; in the old days hardly anyone got 100,000 miles out of their car and now if you pull a cylinder head off a 150,000 mile car the cylinders look just as fresh as the day they left the factory.
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