Prosport Air / Fuel Ratio Gauge

Prosport Air / Fuel Ratio Gauges: Wideband Precision for Street and Track

Monitoring your engine's air/fuel mixture isn't just a tuner's obsession — it's a fundamental safeguard for any performance build. Running too lean risks catastrophic detonation, while running too rich wastes fuel and robs power. That's where a quality air/fuel ratio gauge earns its place on the dashboard, and Prosport has spent decades refining exactly this kind of instrumentation.

Prosport brings over 40 years of gauge-making experience to the AFR category, positioning itself as a brand that bridges the gap between budget no-name units and expensive OEM-grade systems. Prosport fills a niche between budget no-name brands and premium OEM-style units, with their EVO digital series offering dual-color readouts and peak-hold functions at a lower price point than competitors. For street drivers and track-day enthusiasts alike, that combination of accuracy and accessibility is a major draw.

Wideband AFR Kits Built Around the Bosch LSU 4.9 Sensor

The centerpiece of Prosport's AFR lineup is their wideband gauge kit. Utilizing the latest Bosch wideband O2 sensor — a 5-wire heated LSU 4.9 — these gauges deliver a reading range of 10.0:1 to 20.0:1 AFR. That broad range covers everything from a rich cold-start warm-up all the way through lean cruise conditions, making the gauge equally useful for everyday driving diagnostics and aggressive track tuning sessions.

Each complete kit includes the Bosch 4.9 five-wire heated oxygen sensor, a weld-in bung, a mounting cup, and a 10-foot gauge-to-sensor wiring harness. The plug-and-play design means less time chasing wires and more time on the dyno or the track.

EVO Series: Digital Intelligence in a 52mm Shell

Prosport's EVO Series represents the brand's most advanced approach to AFR display. The EVO Series features a 270° dial sweep dual-color digital gauge. Backlighting can be switched between red, white, green, or blue at the touch of a button , letting owners match the gauge to any interior aesthetic. The black bezel and black case keep the gauge completely blacked out when the ignition is off — a clean, stealth look that suits everything from JDM builds to modern sport compacts.

Beyond aesthetics, the EVO Series packs real functional intelligence. The warning function — both audible and visual — is fully programmable to any AFR level, with changes made directly via buttons on the face of the gauge. All Premium Series gauges perform a dramatic opening ceremony with a full pointer sweep each time the vehicle is turned on and off , a self-check feature that confirms the gauge is operating correctly before every drive.

Flexible Signal Input: Narrow Band or Wideband

One standout feature on Prosport's digital AFR gauge is its signal flexibility. The gauge can be set to read narrow band (0–1V) or wideband (0–5V) with the flick of a switch on the back, meaning it can work with a stock narrow band O2 sensor or pair with a wideband controller to display a 0–5V signal. This makes it a practical option whether you're monitoring a mildly modified daily driver or a fully built forced-induction engine.

The kit also includes a UEGO control box, a weld-in bung, instructions, and a 10-foot wiring harness, as well as a 0–5 volt output signal for data logging and a 0–1 volt output signal. That data logging output is particularly valuable for builders who want to capture long-term AFR trends across a wide range of operating conditions.

Why Choose Prosport for AFR Monitoring?

• Bosch LSU 4.9 sensor included — industry-standard accuracy right out of the box
• Wide 10.0:1–20.0:1 reading range — covers rich cold-start to lean cruise and everything in between
• Fully programmable visual and audible warnings — set your own AFR threshold for engine protection
• Peak recall function — review the highest or lowest AFR readings captured during a run
• Narrow band / wideband switch — one gauge, two signal modes for maximum compatibility
• Daisy-chain power wiring — simplifies multi-gauge installations
• Complete plug-and-play kit — sensor, bung, harness, and hardware included

Driven by the concept of "visible speed," Prosport's engineers strive to create instruments that are immediately readable, so drivers have the information they need as quickly as possible. In the world of AFR monitoring, where a moment's hesitation can mean the difference between a safe pull and a damaged engine, that philosophy translates directly into real-world value.