For the better part of a century, a long list of technology has landed in the hands of everyday people whose origins began elsewhere. For example, NASA needed battery-powered cordless tools to work on satellites or the space station. Now, we use that same technology to help disassemble and reassemble the project in our garage faster than ever. Disc brakes have been a common sight in production cars since the 1970s, but they owe their roots to motor racing from the 1950s. Carbon fiber started in aviation and space programs before making its way into motorsport; now it helps keep the weight down on modern-day performance cars that suffer from excess bloat.

By the late ‘80s and early ‘90s, the oxygen sensor had become commonplace in vehicles on dealer lots. It was developed when electronic fuel injection started hitting production cars in the late ‘70s, and its original function was to keep your vehicle’s air-fuel ratio (AFR) constant and steady for the emissions coming out of the tailpipe. But, as the years went on, engineers were able to use this technology to fine-tune engines in daily drivers, as well as your performance car, to extract more power out of engines, keeping both the EPA and our right foot happy. Now, whether you have a carburetor or electronic fuel injection; a small engine or large displacement V8; naturally aspirated or boosted, you can utilize that same technology to pinpoint your AFR with Daytona Sensors WEGO wideband kits.

Daytona Sensors WEGO Wideband Kits not only include the sensors but even the weld-in bung for your exhaust.

What is an O2 sensor?

An oxygen (O2) sensor is an electronic sensor mounted in an engine’s exhaust system that tells the EFI control module, called an ECU or PCM, how much oxygen is in the exhaust. This communicates the AFR, using a range of voltage so the computer can make fueling adjustments if the mixture  is too lean or too rich. It is active the entire time the engine is running, and modern sensors can communicate this data up to one hundred times per second. An oxygen sensor can do this by allowing exhaust gasses to come into the tip of the sensor inside the exhaust pipe and then heating it to charge the ions in the gasses to create a voltage. This is why modern O2 sensors are multi-wired; they have a built-in heater element. The difference between the oxygen content in the sensor and the oxygen content in the exhaust is what determines how much voltage is produced. Oxygen sensors come in different forms, but the most common are narrowband and wideband.

Note the large 6-pin connector for the supplied oxygen sensors and the small holes in the tip of the sensor to read AFR.

The narrowband O2 sensor was the original style of oxygen sensor that can trace its roots back to the late 1970s. This single-wire design required the exhaust to heat them up instead of a built-in electric heater element and only served one simple purpose: to tell the ECU if it was lean or rich. However, the major flaw with a narrowband-style sensor lies in its inability to say by how much, hence the “narrow” in the narrowband name; it gives out a very narrow window of information to the computer. A narrowband O2 sensor communicates on a scale of 0 to 1 volt; 0 is too lean, and 1 volt means too rich. In the early days of EFI and in closed-loop mode, this functioned perfectly fine, and the OEM still uses this style of sensor in some applications. However, the downfall is that the engine’s computer doesn’t get an exact value for a given air-fuel ratio.

Like walking down a hallway blindfolded, you know what direction to go, but you never know how close either wall is to you, so you stumble back and forth as you make your way down the hall. A narrowband O2 sensor functions the same way, so the ECU is constantly adjusting the fuel mixture from lean to rich to try to get the engine to run the ideal stoichiometric air-fuel ratio for a gasoline engine of 14.7 parts air to 1 part fuel, or as some say, a stoich of 14.7:1. At high loads and max output operations, the computer can’t use this “guessing game” type of information to calibrate the air-fuel ratio, so it runs in open-loop mode, relying on preprogrammed fuel tables and the other sensors in the EFI system to provide the proper amount of fuel. This was still a big step up from carburetors for a daily commuter car or truck, but engineers knew they could do better.

Can the engine computer gather the correct information to tweak the mixture for an engine on the fly, for both idle and cruising and for maximum performance? Yes, that’s where the wideband oxygen sensor comes in. A wideband O2 sensor works on a scale of 0 to 5 volts, so the ECU now gets a wide range of information about the fuel mixture from about 10:1 to 20:1 AFR. These types of sensors can be identified by the 5 or 6 wires and bulkier electrical connector compared to the narrowband’s four (or fewer) wires to function. 

Now, the computer can take this information to fine-tune the air-fuel ratio for pinpoint accuracy instead of just guessing. EFI tuners today use wideband O2 sensors on chassis dynos along with tuning software to properly tune a performance vehicle. Monitoring the AFR of your high-performance vehicle, on or off-road, is highly recommended. Daytona Sensors WEGO Systems allows the end user to see the AFR at any given moment, utilizing the modern wideband oxygen sensor.

Daytona Sensors WEGO III Single Channel Wideband System. With only one O2 sensor and bolt-on style interface module.

How does the WEGO System work?

The Daytona Sensors WEGO Systems are a versatile tuning aid for all carbureted and fuel-injected engines. Yes, you read that right. Due to their stand-alone design, you can use the WEGO System to help you precisely calibrate the fueling on your classic carbed V8, motorcycle, or even a small displacement shifter-kart. No more pulling spark plugs after every jet change to see how close or far away you are with your air-fuel mixture. 

At the heart of the kit is the interface module that takes the 0-to-5-volt signal from the wideband O2 sensor and converts it to a digital readout that you can monitor in real-time and data log on a laptop with the included software. They utilize the high-quality and common Bosch LSU 4.2 five-wire wideband oxygen sensor with 18×1.5mm threads to fit normal oxygen sensor bungs. That makes it easy for you to install into your existing exhaust or have a local exhaust shop weld in a new bung. The compact interface module displays a digital AFR readout. Also, it logs over two hours of data, including AFR, engine RPM, and a spare 0-5V analog input for sensors such as throttle position or manifold pressure. The kits include the software and a USB cable and work with most laptops and computers running a wide range of Windows operating systems, from the current Windows 10 down to Windows XP from over two decades ago, so you don’t have to rush to your local neighborhood electronic box store to buy the latest and greatest laptop to benefit from what these WEGO system kits have to offer.

Daytona Sensors offers their WEGO systems in a single-channel or dual-channel setup. The single-channel kits utilize only one sensor, making them suitable for single exhausts, small engines, other power sports engines, or even a single turbo setup. The dual-channel kits offer two sensors and two digital readouts that are better suited for engines that have two banks of exhaust, especially a truck with true dual exhaust, a Cobra kit-car or a classic Corvette with side pipes, as these exhaust systems don’t utilize a crossover pipe like an X-pipe or an H-pipe. 

Whether you choose the single- or dual-channel to suit your application, all WEGO systems are highly accurate. Over the 10.3 to 19.5 AFR range, they have a reported error factor of less than one percent. You can also choose between the WEGO III system, which has an interface module that is designed to be permanently mounted with its compact size.

Each interface module features adjustments for the ‘clean air calibration’ process to ensure each sensor is reading perfectly. In this case, the two blue dials for this dual channel kit.

Air-Fuel Ratio VS Lambda

Daytona Sensors also offers the ability to order their kits to output and display Lambda instead of AFR. But what is “Lambda,’ and why would one opt to order their kit in this way? 

The fundamental difference is that AFR describes the actual ratio between oxygen and fuel, while Lambda, on the other hand, expresses the percentage of difference  between the actual AFR and the stoichiometric AFR. You can think of Lambda as a unit of measurement that shows how much richer or leaner the air-fuel ratio is compared to stoichiometric as a percentage instead of just a fixed unit. A number of 1.0 means that the engine is running at a stoichiometric AFR, and numbers larger than 1.0 represent a lean mixture, while numbers less than 1.0 represent a rich mixture. For instance, a Lambda of 1.15 means the AFR is 15-percent lean, and a Lambda of 0.85 means the AFR is 15-percent rich. Some prefer this because they can figure out the simple math in their head while monitoring and tuning the engine instead of trying to remember target figures

No details are missed in the WEGO Wideband kits, including everything you need like the weld-in O2 bungs as well as all the parts for the electrical connectors.

Another thing to consider is that for the wide range of fuels we can run in our engines, stoichiometric changes exist for different kinds of fuels. Everyone is familiar with pump gasoline and its stoich of 14.7:1, but this changes for different alcohols and alcohol blends. Ethanol alcohol, specifically the E85 blend you can find at your local gas station, has a stoich of 9.7:1. Methanol alcohol has a stoich of 6.4:1. Even something as mild as today’s E10, which is 10-percent ethanol and 90-percent gasoline, has a stoich of 14.08:1. While stoich changes for these different fuels, the Lambda does not, because the stoich, regardless of what type of fuel, is always 1.0. 

Whether it’s pump gas, E10, E85, E98, methanol, etc., the Lambda is still just 1.0, making this unit of measurement the go-to choice for most tuners, race teams, and professionals due to its fool-proof simplicity. At the end of the day, choosing to configure your Daytona Sensors WEGO kit to show Lambda instead of the more common AFR is a personal preference, one that is usually reserved for experienced professional tuners that also deal with a wide range of fuel types when tuning engines daily for a living.

Daytona Sensors WEGO III Single Channel Wideband System. With an O2 sensor for each bank and bolt-on style interface module.

Once you start modifying the engine in your project car, racecar, or custom engine build you’ve been dreaming of from the ground up, the ability to monitor your air-fuel ratio is paramount for maximum performance and a long service life. Running too rich or too lean can ruin all your hard work and bank account in a very short amount of time. So don’t try to walk down the hallway blindfolded playing the guessing game; pinpoint your AFR with Daytona Sensors WEGO wideband kits.