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Does a narrowband switchpoint matter?
Posted: Wed May 03, 2006 10:06 pm
by Zendalar
I was wondering if it made any point switching my EGO switchpoint to 0.784 rather than 0.5XX which is the default?
I am getting these certain lean "spikes" at certain points after using autotune. I was checking the logs and most of the time the voltage is over 0.800, but to be certain, wanted to ask here.
Which is better, 0.5XX or 0.784? (According to logs, there is a very rapid and straight drop from 0.9 to 0)
Thanks.
Posted: Thu May 04, 2006 5:39 am
by 78Spit1500Fed
Narrow band sensors will swing from around 1 volt to zero volts VERY quickly. They truly are an on/off type of sensor, though many would suggest otherwise. The reality is that even if there were a period of transition that were useful for tuning or metering purposes around stociometric, it would be different for each sensor and highly subject to temperature variations.
With that in mind, it would reason that any switchpoint between your minimum and maximum voltages would be suitable for making that lean/rich determination; the .5v threshold is halfway between min and max, and according to most OEM specifications, is the point where stochiometric can most reliably be expected.
Moving that switchpoint by a couple of tenths (say to .4 or .6) would not adversely affect the performance of your motor... but the closer you get to the minimum and maximum values, the less likely you're actually indicating a stochiometric mixture to MegaSquirt.
My advice; leave it alone. Find out why there are lean spikes and solve that problem first. Dive into the log and find what MAP and RPM bins would affect your spikes and enrich them. Also, take into consideration any accel/decel enrichments you may have activated.
-Brian