.: XT660.com - The #1 XT660 Resource :. - O2 sensor eliminator mod (By Kev with the help of dazmatic)

[QUOTE=Chenko;194072]I have a question :-) after installing both O2 sensor eliminator + fuel mod and tweaking the setting on the latter to find what works best with my configuration, shall I also tweak CO value No need to the fuel mod adjusts the A/F ratio across the whole fuel map & rev range. and TPS angle value No do not play with the TPS value 16 to 18 is standard? If so, why? And are there any guidelines/advice on how to tweak those values after installing Kev's mods? I read the sticky threads wih great interest, but I fail to understand how they all make for different reactions in the fueling, since in the way I see they work they all seem to richen (or lighten) AF ratio. I'm sure I'm missing a major point here :-

Why do we need this O2 controller.
There are 2 sides to a fuel map, closed & open loop circuits.

A Power Commander or any other type of fuel mod can only adjust the fuel map in the open loop, the open loop circuit is when the ECU sees sudden acceleration, any RPM above 4500rpm & all throttle openings over 20%, cruising or not cruising.

The closed loop is used for emission control, it comes into effect after a coolant temp of 70 degrees C, when the ECU sees a constant throttle opening of below 20% & below 4500rpm, the ECU takes voltage readings from the O2 sensor & will lean the A/F ratio out until it sees a A/F ratio of 14.7:1.

The resistor type Eliminators do not work we have proven this, at the time of proving they do not work Dynojet pulled all the XT660 resistor type O2 eliminators from their for sale lists.

The ECU constantly looks for 0 to1 volt square wave signal, by unplugging the O2 sensor & fitting a resistor it sends a constant voltage signal to the ECU, after a few Min's the ECU see this as an corrupt signal & then constantly switches the A/F ratio up & down, in this state the bike is not tuneable.

The only 2 types that have been proven to work are Dynojet O2 Optimizer & my O2 eliminator/controller.

By controlling the closed loop circuit we are able to reduce the surging when you are cruising, with one of the latest O2 devices when the ECU switches between the open & closed loop circuits the transition is much smoother as the A/F ratios are closer to each other, see table below.

Open loop for most HP & Torque= 13.2:1 Tuned by a Power Commander or one of my fuel mods.
Closed loop A/F ratio = 14.7:1 Tuned by the O2 sensor no O2 controller mod fitted is to lean causes surging, when switching from closed loop 14.7:1 to open loop 13.2:1 you can feel this surging at cruising speeds.
Closed Loop A/F ratio = 13.6:1 Tuned by Kev's O2 Controller, now with the switching between closed loop 13.6:1 & open loop 13.2:1 the bikes surging is greatly reduced.

This O2 Controller mod can be used on a completely standard XT as well any XT with extra filters & pipes, can be used with my fuel mods + PCIII & PCV.

The O2 Controller is only part of the equation to reduce the surging but is one of the most important ones in reducing the surging. A good fuel map for open loop tuning + a good chain & sprockets correctly adjusted & no free play in the rear sprocket holder rubbers. Do all the above & your bike will ride like a dream.

My Fuel mod adjusts the open loop mapping, it changes the voltage signal from the ambient air temp, the air temp sender is a negative temperature coefficient sensor which means the colder it is the more resistance is applied to the voltage signal, when my fuel mod is turned clockwise the resistance is increased so the voltage signal to the ECU is altered with more resistance the ECU sees this signal as a colder ambient air temp so increases the fuelling in the 3D mapping.