PRODUCT DETAILS
AEM Wideband AFR Gauge - Digital Air/Fuel Ratio Gauge with Bosch LSU 4.9 Sensor
Tuning your car or running boost? You need a wideband AFR gauge so you actually know if you're running lean and about to blow your motor. The AEM wideband AFR gauge shows you your air/fuel ratio in real time on a big three-digit LED screen. When you're on a pull and you see your AFR climbing into the 15s or 16s under boost, you know you're about to detonate. That's when you lift and save your motor instead of sending a rod through your block. If you're modifying your car at all—intake, exhaust, cams, turbo, supercharger, E85—you need a wideband gauge. Don't tune blind.
Here's Why You Actually Need This
Your factory narrowband O2 sensor's useless for tuning. It can't tell you your exact AFR. It just tells your ECU "rich" or "lean" with no numbers. A wideband O2 sensor measures your exact AFR from stupid rich (like 10.0:1) to dangerously lean (20.0:1). When you're tuning, you need to know your exact AFR so you don't run lean under boost and blow your ringlands. The AEM wideband gauge shows you your AFR in real time. You're watching the numbers on the gauge while you're making a pull. If you see it drift lean, you know something's wrong before you hear knocking.
Bosch LSU 4.9 Sensor - Fast and Accurate
The AEM gauge uses a Bosch LSU 4.9 wideband O2 sensor (comes with the gauge if you order the "Sensor Yes" option). The Bosch LSU 4.9's a fast-response sensor, which means when you stab the throttle and your AFR changes, you see it on the gauge immediately. You're not waiting two seconds for the gauge to catch up. The sensor screws into your exhaust pipe using an M18x1.5 bung. If your exhaust doesn't have a wideband bung welded in already, you'll need to get one welded in before you install the sensor.
Big LED Display You Can Actually Read
The gauge has a three-digit LED display that shows your AFR in 0.1 steps. You're seeing 14.7, 12.5, 11.0—not some vague needle on a gauge face you can't read. The gauge also has an LED ring around the outside that changes color based on your AFR. Green's stoich, red's rich, blue's lean. When you're making a hard pull, you don't have time to read numbers. You glance at the LED ring. If it's going blue, you're going lean and you lift. That's it.
52mm Gauge - Fits Standard Gauge Pods
The AEM gauge is 52mm (2-1/16"), so it fits into any standard gauge pod or A-pillar gauge mount. You're not hunting for weird custom brackets. It drops right into your gauge pod. The gauge comes with black and silver bezels and black and white gauge faces, so you can match whatever interior you're running.
0-5V Output for Your ECU or Datalogger
The AEM gauge has a 0-5V analog output that you can wire to your standalone ECU, piggyback, or datalogger so it logs your AFR. If you're running Hondata, Haltech, Link, AEM, or any other standalone or piggyback that accepts analog input, you're wiring the 0-5V output to your ECU and logging AFR. The gauge also has AEMnet CAN output if you're running AEM gear. You're logging every pull and sending the logs to your tuner so they can dial in your fuel maps.
What You Get
- AEM X-Series wideband AFR gauge (52mm / 2-1/16")
- Three-digit LED display with 0.1 AFR resolution
- LED ring (green/red/blue for rich/stoich/lean indication)
- Bosch LSU 4.9 wideband O2 sensor (if "Sensor Yes" option selected)
- 0-5V analog output for ECU/datalogger
- AEMnet CAN output
- Black and silver bezels
- Black and white gauge faces
- Gauge controller and wiring harness
You Need This If You're Running
- Turbo - you're verifying AFR under boost so you don't detonate
- Supercharger - same deal, you're watching AFR during pulls
- Big cams - you're dialing in fuel maps for your new cam profile
- E85 - you're monitoring AFR when you switch fuels because E85's stoich is different
- Any bolt-ons - intake, exhaust, headers, you're tuning for them
- Dyno tuning - you're watching AFR in real time while your tuner's adjusting maps
- Street tuning - you're datalogging pulls and sending logs to your remote tuner
Works With
- Any turbocharged or supercharged car
- Any naturally aspirated car you're tuning
- Honda, Acura, Nissan, Mazda, Subaru, Mitsubishi, Toyota, Lexus, BMW, Volkswagen, Audi - basically anything with an exhaust pipe
Note: Wire the 0-5V output to your ECU or datalogger if you want to log AFR. You'll need to configure your ECU or datalogger to read the 0-5V signal correctly (usually 0V = 10.0 AFR, 5V = 20.0 AFR, but check your tuning software). The gauge displays AFR in gasoline equivalents. If you're running E85, you'll need to do the stoich conversion in your head or configure your datalogger to convert it for you. Don't tune your car without a wideband gauge. You're guessing, and guessing kills motors.