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Old 06-03-2011, 04:35 AM   #12 (permalink)
Frank Lee
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Quote:
Originally Posted by texanidiot25 View Post
If I'm not mistaken, the firing order is not as simple as turning off 1-3-5-7, or something like that. It alternates which cylinders are "off" in order to retain some smoothness. Cadillac's Northstar did this as well in limp home mode, using the dead cylinders to air-cool the block, by deactivating different cylinders, but still maintaining a decent level of smoothness.
The limp home alternating isn't for smoothness; it's for the cooling effect you noted.

DOD systems don't alternate which cylinders are idled; it's always the same ones.

For displacement on demand smoothness they resorted to fancy hydraulic/computer controlled motor mounts and such.

FYI DOD: GM displacement on demand technology
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