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Old 01-03-2012, 08:55 AM   #38
roger 04 rt OP
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Joined: Nov 2011
Location: Massachusetts
Oddometer: 2,152
Project Update

In the photos below are the settings for the Innovate Motorsports LC-1 Wideband O2 Sensor that I used on my R1150RT to drive the stock, narrowband O2 sensor inputs to the Motronic. To summarize the project:

--I wanted to smooth out the performance of my motorcycle at low RPMs and remove all sense of hesitation in the 2000 to 4000 RPM band, even though the bike had already been fully tuned and balanced and didn't seem to have any surging.

--My test runs with the GS-911 showed that the R1150 spends almost half its time Closed Loop, meaning using the O2 sensor and toggling the Air Fuel Ratio (AFR) just above and just below 14.7:1. This is a leaner mixture than the so-called Best Power mixture for most engines, and I felt it likely the cause of a "holding back" or lean-ness that I felt in the 2000 to 4000 range.

--I wanted to allow the Motronic to operate the bike as it was designed to do, including Closed Loop with an O2 sensor and CAT.

--I replaced the stock O2 sensor which only allows Closed Loop AFR of 14.7:1 (gasoline) with a Wideband sensor who's AFR could be programmed to something between 13.0:1 and 15.0:1 so that I could find an AFR near 14.7:1 at which the bike ran its best. The product I chose is the Innovate Motorsports LC-1.

At this point using a target AFR of 14.2:1 (actually Lambda = 0.97), the project seems successful. Now the bike seems smooth and powerful from 1,500 RPM to 6,000 RPM--no surge, no hesitation, no stumbling, no "holding back". I can easily drive local roads in 5th gear and now regularly run RPMs around town between 2,500 and 3,500.

The installation is complete and stable but the LC-1 is not an easy Plug 'n Play solution. You have to connect it to power and ground, and have to connect it to the narrowband input wires of the stock O2 sensor. I did it quickly and left 5' of cable attached to the LC-1. I will cut that back, reroute the wires and check noise levels with an oscilloscope to determine the best wire routing. I will also rethink where the LC-1 (weatherproof) gets located.

Below are some screenshots of the LC-1 software and also one from the GS-911 showing its reports of how the Motronic sees the voltage toggling. It looks pretty good.

Thanks to everyone for the comments and support.
Happy Riding in the New Year,

Plots and Comments:

The is the plot of the GS-911 toggling O2 around the setting of Lambda=0.97 or AFR 14.2:1. It goes solidly and regularly above and below the Motronic switching levels and produced a steady stream of cross-counts.

This is the LC-1 first setup page. I left Stoichiometric at 14.7 (rather than adjust to 14.13 of E10 fuel) since it's easier to think in those terms. It only affects the display of operation, not the settings.

Here are the voltage and Lambda settings that created the best O2 toggling waveform. They take into account a 140mV low side offset that I discovered in the Motronic, and produce a sharp change from Lambda=0.965 to 0.975.

I selected updating 12 times per second as a way to keep the Motronic from over-responding to the very sensitive LC-1.

Here are some usual plots with stock O2 sensors according to the GS-911 manufacturer. You can see that the usual plots are a bit jagged. This is because the GS-911 doesn't produce realtime data points, just every 200mS or so. If you go their site they also show some others, including bad plots.:

roger 04 rt screwed with this post 01-04-2012 at 07:46 AM
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