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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Here is a Co to AFR chart: The MG & MGB Experience: Library: CO% to Air Fuel Ratio (AFR) Table

I believe max TQ is at about 13/1 to 13.2/1 for a normally aspirated 911 motor. I have seen a turbo at 13/1 but that takes a lot of heat management and race fuel.

Many tuned performance turbos run in the 12.2/1 range that have more accurate fueling and adaptive systems to protect the motor.

Many turbo cars that come from the factory like WRX's will often run in the mid 10's in stock form on boost. My guess is to protect the motor from detonation.

I believe we tend to want to run in the mid 11's at TQ peak where risk of detonation is highest.

Not an exert on this, just what I believe so far.
Old 04-20-2010, 05:08 PM
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