Thread: Odd AFR issue
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WERK I WERK I is offline
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Join Date: Jan 2003
Location: Wisconsin
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h20cooled7,
The best way to monitor A/F is through data logging under a rolling dyno, but for those who do not have one of those readily available, data logging with something like a Innovate sniffer works very well.

The ideal AFR for a 930 has been beaten to death and for good measure, crucified. It seems it gets richer and richer and richer with each passing thread. My 0.02, because the 930 pancake intake manifold provides less than ideal air distribution across all 6 cylinders and AFR's are the average of all 6 cylinders sampled, you may want to run a little to the left of the peak "Horsepower" curve around 11.8 to 12.5 AFR's. Some even go richer than that, thinking if a little rich is good, more is better. Keep in mind these AFR's are meant to protect from lean conditions from induction compromises and preignition which are variables depending on ignition timing, single versus twin plug, fuel quality, induction - stock versus modified, valve timing, etc.

The closer to stock the engine is, the closer to 11.8 the AFR should be. The closer to ideal the induction system is, the closer to 12.5 the AFR should be, for MAXIMUM POWER, that is.
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'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P

Last edited by WERK I; 04-07-2010 at 06:33 AM..
Old 04-07-2010, 06:31 AM
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