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Old 24-11-2003, 11:35 PM
AKWRX AKWRX is offline
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Join Date: Oct 2003
Location: Juneau, Alaska
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Quote:
Originally Posted by Philip
What I mean is if I find out what the AFR is when water is on can I set that as my target or will it vary due to things I haven't thought of like temperature, etc? Phil
Using the "conventional wisdom" tuning to a target AFR when injecting alcohol, or a water mix does indeed introduce all kinds of new variables. The oxygen sensor data via either A/F, or Lambda units, is affected by many new unknowns. Determining a target A/F ratio in advance of the tuning process may be beyond just difficult. After wrestling with this issue for some time (until my head hurts from reading), the complexities are more than I would like to tackle.

So, my approach will be a more practical, proven path to tune directly from real time peak cylinder pressure, and adjust its position in the power stroke with the iginition timing. The optimum A/F ratio should essentially just fall out by default. It is an "end run" way to figure out the best A/F ratio. From that point, A/F will just be used to monitor the tune for safety purposes only. The techique is well established (Formula 1, Indy, NASCAR, top fuel dragsters, etc.), only the hardware is very, very expensive. Once I can afford the $1250 pressure sensor (spark plug integrated), a DIY system may be able to be put together for about $2K total cost. Anyhow, that's the plan...
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