roger 04 rt
New member
Roger, I really appreciate your generosity in sharing your data on the forum. It sheds a lot of light on an area about which there is much conflicting information. Your data and explanations are clear enough that even a non-technical person like me can follow along, and understand and evaluate for myself what you are doing and what the results are. Very nice!
I've been trying out some of your ideas on my own 2001 R1150GS. First, I found the bike performed better (more power, no evidence of surge) during the first couple of minutes after a cold start when the Motronic is running a more enriched mixture and before it goes to Closed Loop. Then, as you suggested, I disconnected the O2 so the motor would run Open Loop all the time and installed the Booster Plug (thanks for the loan) to enrichen the Open Loop tables in the Motronic. The bike ran beautifully! The surging was gone, throttle roll-on and roll-off were smoother, and the bike ran stronger in the mid-range. (I ran all of these tests with the Cat Code Plug in.)
Yesterday when I was out I decided to do a comparison just to refresh my memory -- I removed the BP, left the O2 disconnected, and reset the Motronic. The surge returned and as near as I could tell the mid-range wasn't as strong, and the throttle on/off was more abrupt. If I'm understanding this correctly, the bike was back at the 14.7 AFR programmed into the Motronic Open Loop tables, confirming that the engine runs better with a richer mixture as provided by the Booster Plug when running Open Loop. I couldn't really tell any difference between Open Loop without Booster Plug, and stock Closed Loop configuration.
If I'm understanding your latest post correctly, it just might be possible that if/when I install an LC-1 on my bike the Motronic might be able adapt the Open Loop tables to function at the same target AFR as the wideband O2 is set at and, if so, could save me the cost of a BP. I'm looking forward to seeing more of your test data with the LC-1 without the Booster Plug to see if you can get the same level of performance as running Open Loop with the Booster Plug. If so, it seems I would have two options -- disconnect O2 and install Booster Plug, or install LC-1.
Keep up the great work, Roger.
Thanks for your comments, I'm glad that you got a good result. Several people have borrowed the BP now for 1150s running Open Loop and gotten similar results.
And yes, I think you have either option. Open Loop and BoosterPlug being the simplest and getting the AFR to 13.8 to 14.2 depending on fuel and bike tolerances; LC-1 retaining full Closed Loop operation and programming flexibility for a specific AFR target.
When I have some more time, I'm going to run a version of the charts below for Open Loop w/Reset Motronic and Open Loop w/Reset Motronic and BoosterPlug so that there is another baseline for all of this.