When contemplating gauges it can be easy to get wrapped up in the style and 'tunable' colors of the dial and overlook the functionality of the unit in question. The AFR gauge is a Top 3 pick for serious tuned cars. An engine's air/fuel ratio is the parts of air in relationship to fuel. The higher the first number (representing air), the leaner the fuel mixture is. The lower the air value number, the richer the mixture. The old adage, "you need to burn more fuel to make more horsepower" is true but only with the caveat "at the proper ratio", which is where AFR gauges come into play.
L-E-Dinosaurs
In the prehistoric era of performance tuning, an air/fuel gauge was a sad collection of LEDs that would sweep from yellow to green to red. There was no real AFR number being displayed, just hints really; yellow was 'rich,' red was 'lean' and the universal signal to lift.
Further, the sensors at work in these "Jurassic period" pieces were so slow, that even if you could jump off the gas with catlike reflexes, odds are the information was so far behind current events in the combustion chamber your motor's fate was most likely already sealed. Back in the day, the only sensors quick enough and accurate enough to do the job right cost thousands of dollars.
Bandwidth Bandwagon
The emergence of wideband O2 sensors into the mainstream tuning market opened the doors for better, faster and more accurate on-board AFR gauge packages. What was once a twisted, slow-mo light show has been transformed into a high-performance tool capable of accuracy within 0.1 AFR with digital-like quickness. Consequently, modern AFR gauges have progressed far beyond metering duty. They can be linked to aftermarket programmable ECUs where they provide an incoming data stream that contributes to the calculation of tuning maps while also playing a role in generating datalogging information.
I-AFRI-Intelligent Gauges Are 21st-Century-Smart
Today, air/fuel ratio gauges are joining the wireless revolution, using Wi-Fi technology to connect the dots.
PLX Devices Kiwi
Wi-Fi iMFD
PDX Devices has developed an AFR gauge that replaces the gauge with a smart phone. The company's Kiwi Wi-Fi iMFD set-up employs a wideband O2 sensor, a sensor module and Wi-Fi interface. The sensor module interprets the information and sends it through the interface to your iPhone, iPod Touch or iPad, which becomes the display unit via an 8O2.11a/b/g connection in adHoc mode. The 'i-device' in question needs to be running a performance metering app, and Rev by DevToaster or Dash Command are the only two apps that currently support this system. The Wi-Fi interface is connected to the car's OBD-II diagnostic port, which means it can display many of the ECU's other operating parameters in real-time gauge format and serve as a mpg monitor, measure horsepower and torque and read and reset CEL codes. Of course a PLX gauge can be wired to the sensor module and mounted like a normal gauge for the more traditional at heart out there. PLX offers sensor modules for other functions such as EGT, boost, fluid pressure, fluid temperature etc.
AEM Electronics X Wi-Fi
AEM has a Wi-Fi-based AFR system of its own. The twist here is the AEM X-Wi-Fi adds exhaust gas temperature monitoring to the mix. Along with the AFR reading from the tried-and-proven wideband UEGO, up to two optional EGT sensors can be added to glean even more precise combustion quality info. The AEM system uses the standard web browser on virtually any Wi-Fi enabled electronic device such as the iPhone, Droid, and Storm2 smart phones or a laptop computer, so no supporting app is required. Wi-Fi integration is attained in Infrastructure mode or AdHoc network mode and can also access WEP-protected networks.
Innovate Motorsports OT-2
The OT-2 from Innovate Motorsports features the company's OpenTune interface that links OBD-II vehicles to an iPhone or iPod Touch. Innovate air/fuel meters and other Innovate Modular Tuning System (MTS) components can be added to expand the functionality of the OT-2 system. LogWorks mobile software, available free of charge from the Apple online app store, is a full-function performance meter that makes the most of the OT-2 OBD-II interface by displaying numerous parameters from the ECU.