In-Car Air-Fuel Ratio Gauge Buyers' Guide - Part Two

In the first part of this two-part series (see In-Car Air-Fuel Ratio Gauge Buyers' Guide - Part One) we highlighted why you’d want an in-car air-fuel ratio gauge and the difference between narrow-band and wide-band AFR gauges. We also kicked off with the specs of the most affordable air-fuel ratio gauges on the market.

In this part we’ll detail the spec of upper-crust narrow-band gauges and their professional grade wide-band cousins...

Up-Market Narrow-Band AFR Meters

A’PEXi Auto Timer

The A’PEXi Auto Timer isn’t pitched as an air-fuel ratio gauge – instead, it’s a sophisticated turbo timer that receives an input from the car’s oxygen sensor to determine idle-down period. But one of the unit’s added features is the ability to show air-fuel ratio (as a numeric air-fuel ratio display or millivolts) and battery voltage. The unit is pre-programmed with a ‘base map’ that correlates oxygen sensor voltage to a specific air-fuel ratio but you can calibrate this relationship in 0.1 AFR steps. It’s advisable to calibrate the unit against a wide-band air-fuel ratio meter.

The Auto Timer is a very compact device that can be mounted almost anywhere in the cabin without attracting too much unwanted attention. It’s available from most Japanese go-fast parts importers. See Sophisticated Timer for our review.

Price: Around AUD$150

AutoMeter Air-Fuel Ratio Gauge

AutoMeter offers a range of air-fuel ratio gauges which are identical in size and specs – only the appearance varies. These gauges are 52.4mm diameter which allows you to mount them like a conventional gauge. A series of LEDs sweep around the edge of the gauge with zones marked Lean, Stoich and Rich. There are 12 different gauge styles including the popular carbon fibre face.

Sold by most speed shops, the AutoMeter AFR gauge is popular for its seamless integration with other AutoMeter gauge products – you can even mount in on the A-pillar. AutoMeter also offers an oxygen sensor kit for vehicles not factory equipped with an oxygen sensor. The kit comprises an oxygen sensor, wiring harness and weld-on exhaust fitting.

Price: AUD$120 to AUD$160.

GReddy Air-Fuel Warning Gauge

Japanese go-fast brand, GReddy, offer an air-fuel ratio gauge that’s similar to the AutoMeter product. However, the GReddy air-fuel gauge has a larger (60mm) face and uses a needle pointer to display mixtures from 16.0:1 to 8.0:1. The gauge has a 270-degree sweep and, as a member of GReddy’s Warning Gauge series, it boasts a warning light, peak recall and peak mode. A silver, white or black face is available – the white and black face units are backlit green while the silver face model is backlit orange. GReddy also sell A-pillar pods suited to their 60mm diameter gauges.

This product is a rare sight in Australia (probably due to its price) but can be purchased through GReddy dealerships.

Price: Around AUD$600.

Saber Air/Fuel Ratio Gauge – Smokey Lens Series

The Saber Smokey Lens Series AFR gauge use a stepper motor controlled needle pointer and is claimed to provide accuracy up to 0.1 degrees of movement. The gauge is invisible when no power is applied, but switch on the ignition and the Lean, Optimal and Rich scale is lit by white LEDs. In low light conditions, the needle is lit red and there’s an inbuilt dimmer function. The gauge is 60mm diameter.

Saber gauges are available through selected go-fast shops, including several on-line based outlets.

Price: Around AUD$165

AC Autotechnic

A relatively unknown brand in Australia, AC Autotechic offers their S7 Invasion Air-Fuel Ratio Gauge. This gauge is 52mm diameter and has an all-black face when switched off. When switched on, the face clears to reveal the super white, blue, red and orange markings. The zones are marked Lean, Stoich and Rich. A white face version is also available.

It’s available from various parts retailers such as http://www.alldayperformance.com.au

Price: AUD$190.

In-Car Wide-Band ARF Gauges

Haltech

Australian programmable management company, Haltech, offers a wide-band Lambda sensor controller which can be configured with an in-house developed display gauge for permanent wide-band AFR monitoring.

The wide-band Lambda sensor controller kit comes with a dedicated wide-band oxygen sensor (which you need to mount in the exhaust) and a control system with inbuilt temperature correction to ensure maximum accuracy. The unit is designed to interface with Haltech management systems (to provide air-fuel data logging) or can be mated to the in-dash display gauge. The display gauge is claimed to offer 0.1 AFR accuracy through a three-digit real-time display combined with an LED graph. The display is 52mm diameter and just 18mm deep so it can be easily mounted in a variety of positions.

The unit comes pre-calibrated and is available through all Haltech agents.

Price: AUD$600 (including sensor controller and display gauge)

AEM

AEM Power offers a wide-band UEGO Controller kit which, although primarily designed to interface with programmable management systems, can be purchased with a dedicated gauge. The gauge is designed to work with AEM’s supplied Bosch 02 sensor.

The gauge unit is 52mm diameter and offers a numeric air-fuel ratio display as well as a 24 LED graph that’s scaled from 11.0:1 to 16:1. The LEDs are green in the rich zone and red in the lean zone. There’s also a handy user-programmable 0 – 5V output that’s useful for data loggers and aftermarket management systems. The unit is claimed accurate to 0.1 AFR.

Price: Available on eBay for around AUD$500.

Tech Edge

The latest release from Tech Edge is the LA1 Cicular Wide-Band Lambda Display. The unit is a conventional 52mm diameter and offers a 30 dot bi-colour (red or green) peripheral display. A numeric air-fuel ratio display is also integrated into the centre of the face.

The LA1 works with all second-generation or newer Tech Edge wide-band units. The 2A unit is designed for use with an inexpensive Bosch LSU sensor and NTK L1H1/L2H2 sensors. Also included is a multi-channel data logging function and you can buy it either pre-built or Do-It-Yourself. For even more features you can step up to the 3-series wide-band units which offer even more functionality and options – we suggest you visit the company’s homepage at http://wbo2.com/ for full details. The gauge and wide-band units are joined using a mainstream RS232connection.

Hand-held wide-band AFR meters (not quite as suitable for in-car mounting) are also available. These are coded LD02 and 2E0.

Price: Complete systems (including a Bosch or NTK sensor) from around AUD$600

So for between AUD$14.95 and around AUD$600 you can kit out your car with any level of air-fuel ratio monitoring equipment. Really, there are no excuses for not having one of ‘em – a cheapie narrow-band gauge at minimum...