19 July, 2006

Project BoDoH (Butt only Dyno on Highway)

The plan:
Get a O2 sensor
Mount on the exhaust
Ride the bike on the highway with varying speeds and revs
Adjust injection fuelling accordingly

Background Information:

Measuring the Exhaust Gas to determine the combustion state of the engine
Oxygen Sensor
Since the early 1980s, oxygen sensors (O2S) and heated oxygen sensors (HO2S) have played a key role in the efficient operation of electronic fuel injected vehicles. In a modern vehicle, the powertrain control module (PCM) relies on information from the oxygen sensor to achieve optimum air/fuel ratio, good engine performance and control exhaust emissions. Understanding fundamentals of oxygen sensor operation, as well as new changes in technology, can help technicians quickly test and diagnose this increasingly important sensor.

Burning gasoline in the combustion chamber of an engine is a chemical reaction with fairly predictable results. Cylinder misfire, poor engine efficiency and high exhaust emissions can be the end result of too much or too little fuel in the combustion chamber. An oxygen sensor can effectively measure these combustion results. Changes in air-to-fuel ratio affect the amount of oxygen (O2) consumed during the combustion process. The best air/fuel ratio for complete combustion and emissions is a stoichiometric 14:7:1 ratio. A rich (or excessive fuel) air/fuel ratio will consume most of the oxygen during the combustion process, resulting in low exhaust oxygen content. Leaner air/fuel ratios will result in somewhat higher exhaust oxygen content. By monitoring oxygen content of the engine exhaust, the PCM can determine the ideal air/fuel ratio and adjust fuel delivery accordingly.

One of the most common types of oxygen sensors is the zirconium dioxide oxygen sensor. The O2 sensing component uses a solid-state electrolyte made up of a zirconic ceramic material that acts like a galvanic battery electrolyte under certain conditions. When the sensing element is cold, the zirconia material behaves similar to an insulator. At elevated temperatures, the zirconia material performs more like a semiconductor, and can generate a characteristic voltage output on the sensor connections.

In construction of the zirconia sensing element, a porous platinum electrode material covers the inner and outer surfaces of the zirconia solid-state electrolyte. The inner surface of the sensing element is exposed to an outside air reference, while hot gases in the exhaust stream surround the sensor's outer portion. Oxygen content of outside air is approximately 21 percent, while exhaust gases have much lower oxygen content - between 1 percent and 3 percent.

Electrical Operation
Differences in the two oxygen levels, and the electrolytic properties existing between the two platinum electrodes, allow ion transfer to take place and generate a small electrical charge. Oxygen ions are electrically charged particles that flow through the zirconia sensing element when there is a disparity in oxygen levels. The greater the ion flow, the higher the voltage produced. Once the zirconia sensor element reaches an operating temperature of 572 degrees Fahrenheit to 680 degrees Fahrenheit, signal voltage output can range from near zero to 1 volt - depending on the oxygen content of the exhaust gases.

Basically, the zirconium O2 sensor compares the oxygen content of exhaust gases with oxygen from outside air. Voltage produced by the O2 sensor depends on the amount of oxygen in the exhaust. If exhaust oxygen content is low, such as a rich air/fuel ratio, the voltage output from the sensor may be as high as 1 volt. A lean air/fuel ratio increases the exhaust oxygen content, resulting in a low voltage from the sensor.

In normal operation, O2 signal voltage is routinely varying from almost zero to 1 volt. An O2 sensor signal voltage above approximately 0.45 volts is recognized by the PCM as a rich exhaust; below 0.45 volts as a lean exhaust. The goal of the PCM is to keep O2 voltage moving across the 0.45 volt rich/lean switch point for optimum fuel efficiency and emissions.

Adjusting the Injection Fuelling of the Bike

Dynojet Power Commander (versions include II, III-r, III USB)

This piggyback system allows the adjustment of the fuel map of the bike allowing more flexible in the delivery of the fuel to the combustion chambers. The use of a laptop and their custom software will do the job nicely.

The bikes

Kiri's bike:
Suzuki Hayabusa GSX1300R K2
32 bit ECU
Power Commander IIIr
Dual Intake cams
HMF Bigbird (4-2-1)

Suzuki Hayabusa GSX1300RX '99
16bit ECU
Power Commander II
Yoshimura Stage 1 cams
HMF Dual (4-2-1-2)
Yoshimura Titanium Endcans
Small Airbox mod


Kiri's bike - revs freely with very good response. Due to the exhaust setup (4-2-1), his bike will be making high horsepower in high revs, making it feel much like a supersports. Reduced weight from his exhaust also helped in improving the entire feel of the handling of the bike. Agile and powerful. <Max speed tested - ~300kph (indicated [meter restricted to 300kph]>

Mine - Looking for more punch (torque) so dialled in a tad more fuel, not as fuel economical as kiri's bike. But gives a consistently wide torque band that keeps the bike pulling from 4000rpm all the way to redline in top gear. Overall still feels like how a stock busa is just that it's stronger throughout the powerband. Bike keeps pulling even after 300kph (indicated). <Max speed tested ~330kph (indicated [meter shows up to 350kph]>

Overall both of us were satisfied with the maps. Will most probably be going for another fine tuning session on the highway.

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