View Single Post
Old 12-20-2011, 07:33 AM   #24
roger 04 rt OP
Beastly Adventurer
roger 04 rt's Avatar
Joined: Nov 2011
Location: Massachusetts
Oddometer: 2,254
Some Data Plots from AFR=14.2

Here are some plots of several thousand data points acquired while running at 14.2 Air Fuel Ratio (AFR). The key observation is that the Motronic is operating normally, unaware that it has been spoofed to run at Lambda=0.965 which is an equivalent gasoline AFR of 14.2.

This an acceleration through a couple of gears with a warm engine. Notice that just like the earlier chart (a few posts back), the Motronic goes into closed loop while the RPM is accelerating. The Motronic doesn't know the Closed Loop AFR is 14.2, but for the rider (me) the engine feels much stronger and smoother because the AFR is richer.

The next two charts show a before (14.7 AFR with Stock Narrow Band O2 Sensor) and after (14.2 AFR with Wideband O2 Sensor and LC-1 connected to the Motronic in place of the Stock Sensor). Although the shapes of the curves are different due to how I have set up the hi/low transitions (something I will continue to experiment with) the key takeaway is that the Mean (average) and Median voltages are nearly identical (about 20 mV different). This suggests that the Motronic is controlling Closed Loop operation and is satisfied that it is in charge, producing the same average Lambda in Closed Loop.

Stock O2 Sensor

Wideband O2 Sensor

Next I will get some highway riding time in.
roger 04 rt is offline   Reply With Quote