5 Best Wideband Gauges – Reviews and Buyer’s Guide
In tuning a high-performance engine, whether it has a reflash or a standalone ECU, a wideband gauge is your best friend.
Basically, this gauge reads the oxygen content in the exhaust system using an oxygen sensor and shows you whether the engine is running rich or lean.
The unit reads and shows you the results wider air-fuel ratios, which means you get more precise results, and this enables you to fine-tune the engine’s performance to get the best air-fuel mix.
That said, you need to have the best wideband gauge so as to achieve the finest tuning and this review covers 5 of the best ones that you can get in the market.
5 Best Wideband Gauges – Reviews
IMAGE | PRODUCT | FEATURES | |
|---|---|---|---|
 | 1.Auto Meter 4379 (Good AFR Gauge) | ||
 | 2.AEM 30-4110 (Best Air-fuel Ratio Gauge) | ||
 | 3. AEM 30-4110 + 30-4406 (AFR & Boost Pressure Gauge Combo) | ||
 | 4.AEM 30-0300 (Innovative Wideband Gauge) | ||
 | 5.Innovate Motorsports 3918 (Cheapest Wideband Gauge) |
PRODUCT |
|---|
1. Auto Meter 4379 – Good AFR Gauge
Editor's Rating: 
(4.5 / 5)
- Sensor: Bosch LSU 4.2
- Range: 10 – 17 AFR
- Size: 2-1/16 inches
Auto Meter’s 4379 fits in this list because of a number of reasons. For starters, it has a digital segment display that shows the air-fuel ratio on a 10 – 17 range, with a resolution of 0.1. Combined with an outer LED radial bar graph display, the kit gives you the most accurate readings and is easy to read.
The gauge also comes as a complete kit, having a Bosch LSU 4.2 oxygen sensor, an 8-foot wiring harness, a weld-in stainless-steel bung, installation instructions and mounting hardware for easy installation. All these make it the top-rated wideband gauge in this review.
Even though the unit is designed for use in gasoline-powered engines, it is highly compatible with most street and race car electrical systems because it can operate in either 12 or 16 volts.
On the downside, the accompanying LSU 4.2 O2 sensor is not as good as the newer 4.9 and its AFR range is not as wide. However, the unit still performs quite well and has a 0 – 4-volt data output feed for laptop tuning, ECU or a data acquisition unit.
Pros:
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2. AEM 30-4110 – Best Air-fuel Ratio Gauge
Editor's Rating: 
(4 / 5)
- Sensor: Bosch LSU 4.9
- Range: 10 – 20 AFR
- Size: 2-1/16 inches
This wideband gauge is one of the best in the market because it features the latest and most accurate Bosch LSU 4.9 sensor, which is by far the best wideband O2 sensor currently.
Additionally, the unit requires no free air sensor calibration as it is laboratory calibrated beforehand. It also gives a wider air-fuel ratio sensing range of 10 – 20 AFR on its digital display.
The gauge is housed inside a 2-1/16-inch (52mm) casing, and this universal size ensures that it fits in most gauge pods, after which it can be mounted anywhere inside your car.
Some slight customization is also built into the gauge’s design, with interchangeable black and white faceplates as well as interchangeable black and silver bezels, all of which are included in the pack.
Other features include a digital display with a .1 resolution, an outer bar graph with an LED needle, and a 0 – 5-volt analog output. However, the included wiring harness is a bit short.
Pros:
Cons:
3. AEM 30-4110 + 30-4406 – AFR & Boost Pressure Gauge Combo
Editor's Rating: 
(4.2 / 5)
- Sensor: Bosch LSU 4.9
- Range: 10 – 20 AFR
- Size: 2-1/16 inches
Though expensive, this product comes as a wideband gauge and boost pressure gauge combo, in which the wideband gauge is the 30-4110 from AEM (like the one above) and the boost pressure gauge is the 30-4406 from the same brand.
The wideband gauge is quite impressive with its 10 – 20 AFR range, and it is supported by the pressure gauge’s -30 to 35 PSI range, which is ideal for both fuel injector and carburetor motors.
All have digital scales, with digital LED displays on the middle section and an outer LED needle, which make the gauges easy to read.
Additionally, all of them come with interchangeable black and white faceplates, as well as black and silver bezels, which customize their looks to your preference. Other features include a 52mm (2-1/16-inch) housing and a 0 – 5-volt analog output.
Pros:
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4. AEM 30-0300 – Innovative Wideband Gauge
Editor's Rating: 
(4.1 / 5)
- Sensor: Bosch LSU 4.9
- Range: 8 – 20 AFR
- Size: 2-1/16 inches
The 30-0300 X-Series from AEM is still very new in their lineup and features the latest, patented X-Digital technology, which gives these controllers the capability to display values that other wideband gauges cannot.
For instance, this one has a much wider range of 8 – 20 AFR and can display these values to the hundredths of %.
Additionally, this technology results in a much faster response time, which improves the wideband feedback control, thereby enabling you to carry out a safer, powerful and more accurate tuning.
On the outside, the gauge features a visually striking faceplate as well as a 7-segment center display that is 87% larger than other AEM units, and this makes it much easier to read.
Other features include compatibility to car electrical systems that run up to 16 volts, auto dimming, and a wiring harness plus a weld-in stainless-steel bung in the kit. However, a boost pressure gauge is not included.
Pros:
Cons:
5. Innovate Motorsports 3918 – Cheapest Wideband Gauge
Editor's Rating: 
(3.7 / 5)
- Sensor: Bosch LSU 4.9
- Range: N/A
- Size: 2-1/16 inches
If you are on a tight budget, you can still buy the 3918 MTX-L Plus from Innovate Motorsports because it is very affordable.
Despite this, the unit comes with the best performing Bosch LSU 4.9 oxygen sensor and it has an enhanced heater control for superior sensor performance in high-performance applications, such as in forced induction engines.
While doing this, a fast-analog output speed keeps the car’s ECU up to date with all air-fuel ratio changes in real time for effective monitoring.
Other features include a large digital display in AFR or Lambda, a programmable digital needle and a 52mm diameter gauge housing plus its interchangeable black and white faceplates and bezels.
However, calibration is required before use, but an instruction manual is included to help you with this.
Pros:
Cons:
How to Buy the Best Wideband Gauge
Selecting a wideband gauge is not as easy as you may think because there is a lot of technical stuff involved. To make it easier for you, here are a few things that you should consider.
#1. Compatibility
A wideband gauge can only be useful if it is compatible with the type of engine that runs your car, and this has to do with two things.
First is the electrical system. Not all cars have the same voltage system. Some are designed to have as high as 20 volts running through the electrical wires around the engine while others are designed to handle 12 volts.
This difference means that you must look for a wideband gauge that will work well at the specific voltage running through your car’s electrical system without being over or underpowered.
The other issue to do with compatibility is on fuel type. Some units are designed for gasoline engines only while others can function properly in different fuel engine types. Make sure you check on this and buy the wideband gauge that matches your engine’s fuel type.
#2. AFR Monitoring
An oxygen sensor can be installed in your engine’s exhaust system without the wideband gauge but this won’t be very helpful.
You need to match the sensor with a compatible gauge so that you can read the information regarding the air-fuel mix, and also pass this data to the ECU for analysis.
For this kind of effective AFR monitoring, you will need a wideband gauge that is able to measure the ratios you are running. For instance, if your engine runs a ratio lower than 10, then the X-series from AEM would work best because it goes down up to 8 AFR.
#3. Accuracy and Performance
Whichever wideband gauge you decide to buy, you should not compromise on accuracy and performance. While there is no reliable way of determining the accuracy of the wideband gauge, at least ensure that the included sensor performs exceptionally well, such as the LSU 4.9.
With a good sensor in the bag, the next thing is that there should be very little or no delay at all between the actual measurement and displaying the results on the gauge.
Ideally, this lag should not be more than half a second because if the transmission delays much further, the results will not be received on time, leading to imprecise recalibration or tuning of the engine.
AEM products are the best at this due to their minimal lag and are highly recommended.
#4. Durability
Whichever product you buy, durability is always a vital factor to consider and for a wideband gauge, this is no different. During the installation process, there is a high probability of dropping the unit at least once and if it is weakly built, some components might break.
Apart from gauge itself, also make sure that the included accessories such as the mounting hardware, bungs, etc. are sturdily built so that the entire setup lasts for a long time once installed.
Conclusion
In conclusion, though not many people know or have even heard of wideband gauges, in the world of engine performance tuning, they are pretty important components for the drivers that want to improve the air-fuel ratio in the combustion chambers for efficiency and max output.
That said, if you are not very familiar with these products, instead of taking chances and ending up with the wrong unit, go through the above review and pick the best wideband gauge that suits you and your engine’s needs.