Tech Tuesday is here again and today we discuss air fuel ratio gauges. Specifically narrowband and wideband gauges and which is best fit for your application. The question itself is a bit of a loaded question but let’s examine what each is, what they do, and why you need one, or more specifically one over the other.
NARROW BAND AFR GAUGE
Cutting through the chase, you need a wideband. A wideband gauge is all about precision. The more precise you can tune your car the better. With a wideband O2 sensor and gauge your car can read the mixture to 00.0. This is important because the difference between 11.5 which may read stoic on a narrowband gauge, and 12.5 which may also read stoic on a narrowband gauge is the difference between a well running motor and a blown motor. Note that the example numbers would probably be for a forced induction application which runs richer then a naturally aspirated engine.
The problem with the narrowband is it only gives you three readings, lean, stoic, and rich. That means it is not nearly as precise as the wideband. Which is why I always recommend a wideband gauge. It’s cheap insurance for a bad tune or if something goes wrong. Response time of the gauge is instantaneous which if you are paying attention means you might actually be able to shut it down before something goes bad. More importantly then the diagnostic capability is the tuning ability it adds. Being able to tune the car with the accuracy of a wideband insures spot on performance and no guess work.
Widebands can be had for $150-400. You are are modifying your car that is probably small change compared to what you will spend. So the bottom line is, if you are going to modify, get yourself a wideband.