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markjenn markjenn is offline
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Join Date: Nov 1999
Location: Bellingham WA
Posts: 3,603
Quote:
Originally Posted by Steve Carlton View Post
I'm not seeing the logic in this. My understanding is retarding the ignition is to delay the explosion so it doesn't finish too early for the position of the piston and cause a knock. I stand by my statement that higher octanes burn more slowly. Engines with knock sensors retard the timing to compensate for the faster-burning, lower octane gas and make less power as a result.
You're absolutely right. I screwed the pooch on the logic of this one. I guess I really don't know why retarding the timing helps control knock, but a lot of references say it is not related to the speed of the burn although what you're saying makes intuitive sense.

- Mark
Old 08-05-2010, 09:09 AM
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