2004 R1150RT Wideband O2 Sensors
I'd like to get some inputs on wide-band O2 sensors for the R1150RT.
As I understand it, under cruise conditions, constant TPS and roughly constant RPM, the Motronic 2.4 goes into Closed Loop operation, cycling between slightly rich and slightly lean with the engine running with an average AFR (air fuel ratio) of 14.7 to 1 as set by the narrow band O2 sensor and Motronic.
Digressing for a moment, in the aircraft that I flew for many years the level flight cruise setting (for a given propeller speed) was to lean the fuel flow until peak EGT (exhaust gas temperature) was achieved; or to lean to peak EGT and then richen the mixture by 25 to 50 degrees F. Peak EGT gave maximum aircraft range, and Peak EGT minus 25 degrees (or so) gave maximum speed (cruise power). (Peak EGT - 25F was also considered kinder to the engine since it was running a bit cooler.)
So if I've got it about right, when I'm cruising on an R1150, the narrow-band O2 sensor is "leaning" the engine to peak EGT and something less than best cruise power for a given condition. That being the case, I'm not surprised that the engine must be carefully tuned and balanced so that it doesn't "surge" from a bit of imbalance (one cylinder being slightly leaner than the other).
Although my particular RT seems to run well, I've got this sense that it would like to sip a bit more fuel while cruising. The BoosterPlug I installed has added some fuel to Open Loop operation but when cruising, Closed Loop O2 operation leans things right back to peak EGT--14.7:1 AFR.
One of the options for richening cruise is to keep the Motronic out of Closed Loop operation by removing or changing the CAT plug to one that tells it that there isn't a catalytic converter. But I'm not sure what AFR or EGT I'd end up with.
So like the blind squirrel looking for a nut, I've been trying to find a plug-n-play replacement for the stock narrow-band O2 sensor or a way to shift it. Today I came across the Innovate Motorsports LC-1 Wideband O2 Sensor.
As I read it, the LC-1 can be used as an Air Fuel meter or as replacement for the stock O2 sensor that can have its AFR programmed over a wide range. In this mode, one of its outputs is in the 0V to 1V range, the same as the stock narrow band O2 sensor.
I've searched this forum and others and can't find a whole lot on the LC-1. Has anyone tried this out on an R1150? What has been your experience? I'd appreciate any thoughts or comments.
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