Premium vs. Regular... answers
#1
08-24-2009, 11:14 PM
Premium vs. Regular... answers
There is a small debate about whether Premium is really required for our cars. Some people say the run Regular for the entire time they have owned the car and have had no problems, so Audi must be, um.. conservative in their fuel recommendations. So, can you run Regular? Well yes and no. Yes you prolly can get away with it in the cooler climates and No you shouldnt becuase it hurts the power output. Here is what Audi has to say:
So, as you can see, running Regular is possible and accounted for in the programing, but you could be running upto 15 degrees retarded! That, my friends, will kill power and mileage. Also, notice that the knock retard is cylinder selective. What this means is cyl #1 might be retarded the full15 degrees, and cyl 3 only 8-10. This introduces vibrations and harmonics into the system. This is never a good thing and could lead to a shorten life of the motor.
Is that $2-3 a full tank worth it?
Detonation Retard:
Knock sensors consist of piezoelectric crystals encased in metal and plastic housings located on each cylinder head, under intake manifold. Vibrations in engine cause crystal to generate small amounts of voltage. This voltage signal is used by PCM to determine necessary timing retardation.
One knock sensor is installed on each head under intake manifold. Using 2 knock sensors makes it possible for system to be more accurate and responsive.
When knocking occurs, ignition timing is retarded until knocking is eliminated. Since engine knock limits vary from cylinder to cylinder, knock regulation is cylinder selective.
Knock control starts when coolant temperature is 104°F (40°C) or above. Ignition angle of knocking cylinder is retarded in steps to a maximum of 12 degrees or until knocking stops. If cylinder knock continues, PCM will switch from premium fuel ignition map to ignition map for regular fuel. This allows ignition timing to be retarded up to 3 additional degrees.
Knock sensors consist of piezoelectric crystals encased in metal and plastic housings located on each cylinder head, under intake manifold. Vibrations in engine cause crystal to generate small amounts of voltage. This voltage signal is used by PCM to determine necessary timing retardation.
One knock sensor is installed on each head under intake manifold. Using 2 knock sensors makes it possible for system to be more accurate and responsive.
When knocking occurs, ignition timing is retarded until knocking is eliminated. Since engine knock limits vary from cylinder to cylinder, knock regulation is cylinder selective.
Knock control starts when coolant temperature is 104°F (40°C) or above. Ignition angle of knocking cylinder is retarded in steps to a maximum of 12 degrees or until knocking stops. If cylinder knock continues, PCM will switch from premium fuel ignition map to ignition map for regular fuel. This allows ignition timing to be retarded up to 3 additional degrees.
Is that $2-3 a full tank worth it?
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