What is a Wideband Oxygen Sensor?

A wideband oxygen sensor (commonly referred to as a wideband O2 sensor) is a sensor that measures the ratio of oxygen to fuel vapor in the exhaust exiting an engine. The measured ratio is expressed as parts of oxygen to fuel. If there is 15 parts of oxygen to every one part of fuel, this would be expressed as an air/fuel ratio of 15 to 1, or 15.0:1.

A wideband oxygen sensor allows the air/fuel ratio to be measured over a very broad range (often from around 5:1 up to around 22:1). The stock oxygen sensor (usually a NARROW-BAND sensor) can only measure the air/fuel ratio over a very narrow range (often from only around 14.5:1 up to 15.0:1).

How does the ECU use a narrowband oxygen sensor?

Your factory Honda ECU uses the output from a narrowband oxygen sensor to adjust fuel trim based on engine operating conditions and environment. The ECU attempts to keep the engine operating around 14.7:1 for optimum engine longevity and fuel efficiency while maintaining low emissions. If the ECU 'sees' an air/fuel ratio of 14.5:1, it will slightly decrease injector duration to lean out the fuel mixture to around 14.7:1. If the ECU 'sees' an air/fuel ratio of 15.0:1, it will increase injector duration to richen the air/fuel mixture. This works well on a stock engine, but for optimum performance an ideal air/fuel ratio is much richer (often from 12.0:1 up to around 13.5:1). The stock narrowband O2 sensor simply cannot distinguish this air/fuel ratio and therefore cannot adequately tell the ECU how much fuel to add or subtract. This is where the advantage of a wideband O2 sensor shines! A wideband oxygen sensor will allow the ECU to read a much 'wider' range of air/fuel values therefore allowing the tuner to make the proper adjustments for optimum performance.

What to look for when purchasing a wideband oxygen sensor:

When using a wideband O2 sensor to read air/fuel ratios and tune an engine, there are several qualities to look for.

1. Accuracy is top priority. If the wideband's readings are inaccurate, you may make fuel adjustments in error resulting in a loss of power or even worse, engine damage.

2. Speed. The wideband must be responsive to changes in air/fuel ratio to allow accurate fuel adjustments for changes in engine rpm and load.

3. Ease of installation/ Compatibility. The wideband oxygen sensor must be compatible with your tuning software, hardware, and installation needs.

For the above mentioned reasons, we HIGHLY suggest the Innovate LC-2 Wideband Sensor. The Innovate LC-2 has proven time and time again to be the most accurate, while maintaining amazingly fast response times to changes in air/fuel values. The LC-2 consists of a built-in sealed wideband controller with simple battery power, accessory power, and ground connections necessary along with both analog and digital outputs that make it extremely flexible. The Innovate LC-2 is our recommended sensor for ANY Honda or Acura and can be used with excellent results on all Crome Pro, Neptune RTP, Hondata S300, and Hondata K-Pro setups.

Update June 2011: Innovate has now released their newest wideband, the Innovate MTX-L Wideband. This wideband includes full digital technology and a built in digital gauge for around the same price as the LC-2. The Innovate MTX-L is hands down the best wideband available for all Honda/ Acura applications where a guage is desired. For more information, we offer the MTX-L here: http://www.hamotorsports.com/innovate-mtxl-wideband.html