AFX NGK Air Fuel Ratio Monitor
Low cost air fuel ratio gauge
Accurate air fuel ratio monitor
Wide band air fuel ratio meter
True wide band UEGO sensor technology
Some think tradition...we think innovation.

NGK AFx Air/Fuel Ratio Monitor $295.95

Professionals in the area of Air/Fuel Ratio Analyzers Since 1985
Welcome to Air Fuel - offering the best state of the art air fuel ratio analyzers , air fuel ratio monitors, and air fuel ratio gauges on the market!

When it comes to high-performance engines the fuel delivery system must be accurately tuned (calibrated) for optimum performance which allows peak torque and power (HP). Highest power occurs when the air fuel ratio is in balance for the air flow ingested by the engine (mass air flow). This can only be accomplished when the EFI engine control module (ECM), engine management system or carburetor is adjusted for proper fuel delivery. The engine mass air flow is determined by engine speed (RPM), efficiency and throttle opening. If the mass air flow (MAF) is known then the quantity of fuel injection can be calculated by the ECM. If the ECM uses a manifold air pressure (MAP) sensor then the speed density calculation will look up the fuel injector pulse width from a table that can be adjusted to achieve the proper air fuel ratio for steady state operation. When a speed density method is used all low load engine speeds (RPM) must be calibrated until the proper air fuel ratio is obtained which is can be 14.6 to 1 (stoichimetric). When the highest power is required and the engine is at wide open throttle (WOT) additional fuel is required. The additional fuel used for power enrichment is typically 1 to 2 air fuel ratios richer (12.5-13.5) than stoichimetric (14.6). Temporarily additional fuel (acceleration enrichment) is also required when the throttle is opened (pump shot).

To obtain the best engine performance tune your fuel injection system accurately by using the AFx or AFM1000a air fuel ratio analyzer, air fuel ratio monitor or air fuel ratio gauge. Internal combustion engines produce power from heat and maximum power for many engines occur when exhaust temperatures are above 1300 degrees F.

Not all Air Fuel Ratio meters perform equally!

Be careful when determining which air fuel ratio meter to purchase. Some brands are not able to qualify or verify the air fuel ratio accuracy as listed in the product specifications, can not be air calibrated, delivers data that is above or below the real air fuel ratio or fails to function when the sensor is above 1300 degrees F. It is normal for the downstream exhaust temperatures to be above 1300 degrees F for many street and high performance racing engines when peak horsepower is reached at high RPM's.

Products offered by Air Fuel are used and recommended by Professional Drag Race Teams, NASCAR, Truck Pullers, Tractor Pullers, Go Karts, Pro Stock Motorcycle manufactures, and  automotive OEM 's such as GM, Ford, Chrysler, BMW, Mercedes, Harley-Davison® and Mercury Marine. We also like to mention S & S Cycle  and Big Dog Motorcycles  use our air fuel ratio analyzers.

You can purchase the best for less at Air Fuel!

  • All of our analyzers offer a feature that allows the user to calibrate the sensor in free air, which provides great accuracy and repeatability at all times on many fuels.
  • Accuracy under any load, at any rpm in the operating range of the engine, is essential to great results on the street or track. is your unfair advantage in dynamic air-fuel ratio performance - offering state of the art air-fuel ratio monitors and air-fuel ratio analyzers at surprisingly low cost.
  • We're a full-service supplier with innovative solutions to your EFI tuning needs, from the cost-effective NGK air-fuel ratio monitor ( AFx ) to the professional-grade air fuel ratio monitor ( AFM1000 ) - targeting your specific needs for your particular high-performance car, automobile, motorcycle, boat, marine, truck puller, or tractor puller.
  • Our air-fuel ratio gauge is one of the best air-fuel ratio analyzers on the market with the adaptability, versatility and technology to support your application.
  • We also sell replacement O2 (UEGO) sensors for your existing air-fuel ratio analyzer, air-fuel ratio monitor, air-fuel ratio gauge or wide band air-fuel ratio meter.

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About the NGK AFX Monitor

AFx = Accurate Information

The AFx is designed as an excellent low cost air fuel ratio monitor that allows anyone the ability to monitor the air to fuel ratio (AFR) of an engine. It is important to be able to accurately measure AFR before adjusting the EFI main fuel tables or changing carburetor main jets. This can now be performed with ease by installing a UEGO sensor into the exhaust system. Many previous designs used a production narrow-band O2 sensor and were not able to provide accurate, repeatable AFR.

True Wideband Technology
The NGK AFx uses a true wideband UEGO (5-wire) sensor mounted in the exhaust stream of the engine. The UEGO senses components in the exhaust which are byproducts of the combustion event. The measured exhaust gases are carbon monoxide, hydrogen, and hydrocarbons when rich (Lambda <1) and oxygen when leaner (Lambda > 1) than stoichimetric (Lambda = 1). This allows the AFx to calculate real time air fuel ratio (AFR). Proper air fuel ratios are necessary for an engine to produce maximum horsepower and torques the AFx provide a solution. Engine performance, performance enthusiasts and tuners can use air fuel ratio information to make adjustments to the fuel delivery system (carburetor, fuel injection) to achieve the maximum horsepower and torque from their engine. This does not use a production O2 sensor.

Versatile And Adaptable
The AFx is compatible with both Bosch LSU and NTK UEGO (wideband) sensors without any changes in hardware or programming and offers superb accuracy (comparable to some laboratory grade systems). If the most cost-effective solution to precise EFI tuning is your goal then the AFx air-fuel ratio analyzer is the best choice for your application.

Cost Effective
Traditionally these types of precision air-fuel ratio monitoring gauges and tuning tools commanded price tags in the thousands of dollars putting them out of reach for most enthusiasts and amateur/grassroots racers. NGK's advances in low cost technology have made this highly accurate gauge affordable.

NGK-NTK is the world leader in gauges, exhaust gas sensors and sensor related technology. They supply OEM oxygen sensor technology to a huge range of Asian, European, and domestic auto manufacturers.

Dynamometer manufacturers and professional tuners demand quality!

Our air fuel ratio products and accessories are purchased and recommended by many engine and chassis dynamometer  manufactures from around the world  to customers who are interested in acquiring accurate air fuel  ratio data. This is also very important to our customers who are professional engine tuners that require assurance the fuel calibration is on the mark, especially with engines that cost over $10,000 each. Our products allow for peak engine performance and lower warranty costs over the life of the engine that is tuned properly. This all started with our first product which is the AFM1000 in 1998 and continues to be the analyzer of choice for professional tuners and engine builders. AFM1000 air fuel ratio analyzer customers include:
Land & Sea
Performance shops with a Dynojet® chassis dynamometer

First class tuning professionals use the AFM1000, Lambda Pro or the AFx to develop quality engine calibrations:
Kenne-Bell Supercharges  
Whipple Superchargers  
Superchips Custom  
UMI Racing  
Westec Performance  
Silverback Performance   
Boost Power  

Why take chance when you can use the best!


*Dynojet is a trademark of Dynojet Corp.