Why do I need to calibrate the O2 sensor?
“Why do I need to calibrate the O2 sensor with Innovate products?” The answer is simple… Accuracy!
Innovate Motorsports is the first wideband O2 device manufacturer on the market that allows the user to field calibrate the O2 sensor. Our patented sensor calibration allows compensation for the two main causes of inaccurate air/fuel ratio data; sensor wear and altitude. The alternative to calibrating your sensor in the field is to rely on the sensor’s Bosch factory calibration. The Bosch factory sensor calibration is done using a fixed atmospheric pressure value that may be incorrect for your location from the start!
Sensor Wear
Most popular wideband systems, including Innovate, utilize the Bosch LSU 4.2 & LSU 4.9 wideband O2 sensor. This sensor has an integrated calibration resistor located in the connector on the plug end. Like all sensors in a vehicle, O2 sensors wear over time and being able to recalibrate the sensor is the only way to ensure continued accuracy. Innovate Motorsports makes it possible for the sensor to be recalibrated because we do not rely on or utilize the Bosch calibration resistor. Without the ability to calibrate, your wideband will continue to rely on the Bosch factory pre-calibrated resistor settings as your sensor wears. The results of doing so have been published by Bosch in a technical document referenced below:
LSU test bench at constant 20 degC gas temp and constant 14.7 PSI ambient.
| New | After 500hr test bench run | After 2000hr test bench run | |
| Calibrated measurement gas for 24.99 AFR |
24.99 ± .73 AFR | 24.99 ± 1.47 AFR | 24.99 ± 2.20 AFR |
| Calibrated measurement gas for 11.76 AFR |
11.76 ± .15 AFR | 11.76 ± .29 AFR | 11.76 ± .59 AFR |
According to the Bosch spec the sensor leaves the factory with a ± margin of error of .15 AFR. In IDEAL lab conditions sensor wear will cause the sensor to drift to an accuracy of ± .29 AFR after approximately 500 hours and ± .59 AFR after approximately 2000 hours. In aftermarket performance applications where engines typically see richer conditions with higher exhaust gas temperatures, the sensor will degrade at a greatly accelerated rate compared to the Bosch spec. Other factors such as detergents, additives in the fuel, sensor placement and lead will also accelerate sensor wear even further.
The Innovate Motorsports patented digital wideband sensor controller technology eliminates any and all inaccuracies caused by sensor wear. The simple and quick free air calibration process will ensure that you have measurements accurate to ± .1 AFR for the life of the sensor.
Innovate Motorsports’ recommended calibration schedule:
| Normally aspirated daily driver | Calibrate before installation of the new sensor. Calibrate the sensor again after 3 months of use. Thereafter calibrate once a year or every 20,000 miles, whichever comes first. |
| Turbo car, daily driver (tuned rich) | Calibrate before installation of the new sensor. Calibrate the sensor again after 3 months of use. Thereafter calibrate twice a year or every 10,000 miles, whichever comes first. |
| Race car (running leaded race fuel) | Calibrate before the new sensor. Calibrate once per race weekend. |
| Dyno use | Calibrate the new sensor. Calibrate every 2-3 days, depending on usage. |
Altitude Compensation
Changes in altitude will also affect the accuracy of the measurements.
It is important to note the Bosch spec tests the accuracy of the sensor at 14.7 PSI atmospheric pressure (sea level). In the same way that the pre-calibrated resistor can not compensate for sensor wear, it can not compensate for changes in altitude. To illustrate how important a difference in altitude we can look at the difference between Innovate Motorsports’ office in Cypress, CA which is at sea level, and Willow Springs Raceway in Rosamond, CA. The difference in altitude is approximately 2400 ft. between the two locations; this will make a difference in your measurements by as much as .2 AFR. If you do not have the ability to calibrate your sensor, and you happen to live in Denver (5280 ft. above sea level), your readings will be incorrect right from the start and will progressively get worse as the sensor degrades.
Conclusion
The purpose of installing a wideband O2 system in a high performance engine is to accurately monitor the engine’s operating air/fuel ratio to ensure maximum performance and safety. If you are using a wideband system that does not allow the sensor to be recalibrated, you are putting your engine at risk. Whether you only perform the simple calibration once when you first install a sensor, or at the recommended intervals; Innovate Motorsports’ patented digital wideband O2 sensor controller technology will ensure that you have the fastest and most accurate wideband instrument available at any price.
The difference between a wideband that does not require calibration and the Innovate Motorsports wideband is ACCURACY.
