Thread: TIS
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Old 06-27-2011, 11:44 AM
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Quote:
Originally Posted by diesaroo View Post
One SIB that really struck me was SI B13 02 10. BMW evidently by either a special testing device, or by interrogating the computer can determine for gasoline engines, what octane level is in the fuel you have been using over the life of the vehicle, or for diesel, the cetane number of the fuel most often used.
You don't actually measure octane when you test a fuel, you measure knock and compare it to the knock from a reference fuel in a test engine under controlled conditions. BMW could easily determine how much the timing was being retarded in response to measured knock, but that wouldn't measure octane, because additional variables of altitude, ambient temperature, carbon buildup, etc, would all impact knock.
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