Lamco Gauges - The Holy Grail


If you dream of getting your Lamco gauges working properly (like mine in the video above) you've come to the right place. In the following sections I'll provide a full technical overview of everything I've learned about them in over 24 months of research and experimentation. I'll provide scientific calibration curves along with aftermarket sensors that I've tested and matched to them.

I did this research myself because I just wanted to get mine working at a reasonable price. I then realised there are lots of people out there stuck, just like I was, so I started making complete plug-and-play kits which I now ship all over the world. There is precious little information out there on these gauges so I hope this knowledge article sets the record straight and provides a definitive high quality resource for the community.

It would be remiss of me not to mention the famous Lamco Info Thread on rs25.com which was a great help to get me started. Enjoy.

The Key Problems

  1. The original sensors that drive the gauges are no longer manufactured
  2. Little is understood about the gauge calibration curves (making it hard to match sensors)
  3. Most gauge sets on the market are sold bare with no wiring
  4. If you find an OEM sensor and wiring package, it's crazy expensive (~$1500USD)

I've solved all of these issues with my kits, supplying a custom made harness with gauge plugs, matched aftermarket sensors, engine block adaptors and heat-shielded sensor wire looms with plugs attached.

General Overview

Lamco manufactured gauges were found on a limited number of 90's era Japanese performance cars including the Subaru WRX & Forester, Mitsubuish EVO and even the Toyota MR2 AW11. They were often clustered in sets of 3. They are notably a small form factor at a narrow outside diameter of ~41mm, which is much smaller than the standard gauges size standards of 52mm and 60mm in the marketplace today. This allows them to fit compactly as a cluster of 3 gauges into a standard radio DIN cavity, as pictured. In fact, they are much more similar to motorcycle gauges, with their smaller form factor and tiny backlight bulbs (2W T5 globes).

How many types exist? (5)
There are five known types including: battery voltage, boost/vac, oil temperature (150C max), oil pressure and ambient air temperature (50C max). There are a few subvariants within each of these 5 classes (e.g boost and vacuum gauges measuring different maximums). There are no functional differences between black and white faced gauges.

Which cars had Lamco gauges?
The gauges had their golden era in the 1990's and shipped standard on selected models of Subaru (WRX and Forester), Mitsubish Evolution series, Toyota MR2 (AW11) and, believe it or not, the lesser known Mazda Autozam AZ1!

Subaru
Lamcos came installed on a limited range of Subaru WRX and Foresters in the period 1992 - 2002. These were with the turbo 2.0L EJ20T or 2.5L EJ25T. The exact setup and colour of gauges varied based on the specific model and whether it was Japanese/European delivered (JDM/EDM) or USA delivered (USDM). I believe it was typically the Type R and Type RA spec vehicles that came with these gauges OEM, however I could be wrong. They are totally interchangeable and can be basically installed in any equivalent series.

GC/GF = white faced (1992-2000 WRX hatch and sedan)
SF/GD = black faced (~1997 Forester, 2000-2002 bug-eye WRX)

There are no functional differences between black and white faced gauges: they are identical in terms of internal operation. There are however a number of configuration and mounting variations ranging from 3 gauge radio DIN style clusters to a 3-gauge high mount dash pod mount (WRX) with a 4th gauge mounted to the steering column. (JDM spec Type RA).‍

Mitsubishi
The Mitsubishi Evolution series and Galant VR4 equipped with the 4G63T engine (1992 - 2007) in some models shipped with black-faced Mitsubishi branded Lamco gauges. These are identical in operation and calibration to the white and black faced Subaru Lamco gauges (I've tested them)

The black faced gauges were mounted in a radio DIN triple cluster in the evolution series ranging from Evo 1 - Evo 8 MR in selected models (to the best of my knowledge). The pictures above are from an Evo 8 MR. A typical cluster consists of battery voltage, oil temperature and boost/VAC. I do not believe any of the evo models came with the oil pressure Lamco gauge, this variant was only found in the Subarus.

Toyota (unproven)
Toyota's first edition MR2, the AW11, is rumoured to have a rare 3 gauge high mount cluster that had Lamcos in some variants, but I've yet to verify this with hard evidence.

Above: I havent found an AW11 interior showing standard Lamco gauges (left) but some racing spec ones appear to have what was rumoured, although this could just be aftermarket (right).

Mazda
The less known Mazda Autozam (AZ1) shipped with Lamco gauges in selected models. It's very hard to track down photographs but some members of the community have kindly sent me these. (Thanks to Thomas from California, USA)

Above: The original brochure contains details of a vertical triple gauge lamco cluster (left). Here is a shot from an owner in the USA (right)

Gauge 1 - Battery Voltage

This gauge is common to most of the sets and acts as a simple voltmeter to the main electrical system. With the engine off it will show battery voltage, and when the engine is running, you will see alternator voltage, usually around 13-14V. No sensor is required for this gauge as the gauge itself is the sensor. It simply needs the supply voltage from the car.

GAUGE PINOUTS
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Not connected
PIN4: Not connected
PIN5: Accessory ON (12V+ switched)

Gauge 2 - Boost/VAC

There are a few variants of this gauge, with some mounted on the steering column as a stand-alone (JDM spec) and some in the 3-gauge cluster, along with different face colours, but it's just a simple mechanical boost gauge with a 2 pin backlight. It needs a vacuum line running to it from the engine intake manifold.

GAUGE PINOUTS
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)

Gauge 3 - Oil Temperature

This gauge is designed to measure oil temperature and reads up to 150C (typical oil temperature is 80-110C once the engine is warmed up and is dependent on load). It is identical in function in the black and white faced variants. It measures resistance (ohms) and is one of the most difficult of all the Lamco gauges to get working accurately because it is designed to work specifically with the original temperature sensor manufactured for it, which is no longer available.

The key problem is most temperature sensors are a thermistor probe, which is a variable resistor whose resistance changes with temperature. The properties of these types of probes mean that there is not a linear relationship between temp and resistance: it's a curve that is unique to the physical properties of the sensor. These curves vary wildly between different sensors and they mean that even if the gauge might read accurately at one temperature, it could be way off at another (due to the non-linear relationship). The challenge is to find a currently available sensor that closely matches the characteristics of the original sensor.

For Subarus (unsure for Mitsubishi but perhaps the same), the OEM oil temperature sensor that drives this gauge (pictured above-left) was embedded in the oil sump plug. This meant it was prone to damage and is one of the reasons they are so hard to find now intact. The AEM sensor I have matched to this (pictured above-right) has a standard 1/8 NPT (taper) thread and is not designed to mount in the sump. Instead it must be mounted directly into the engine block oil gallery or on an oil filter sandwich plate.

Reverse engineering the gauge secrets
In order to find a suitable sensor for this gauge, I have reverse engineered the gauge calibration curve by simulating the resistance output from a sensor. I powered up the gauge and connected a potentiometer (variable resistor) across pin 3 and pin 4, modifying the resistance until I got a reading. I then repeated this process until I had a resistances that corresponded to every main temperature point on the gauge, and produced a curve (pictured below). This curve could then be used to match aftermarket temperature sensors by plotting them on the same graph and finding the best match possible. 

The results below are my experimental measurements that show the true gauge calibration (resistance inputs that correspond to a temperature) with the calibration of the AEM30-2012 temp sensor. It's not a perfect match and the gauge will read around 5-10C below actual under around 80C, but as the oil warms up, the error reduces to a high accuracy above 80C. This is WAY better than any other sensor calibration I've found in the marketplace. This my friends, is the holy grail.

RECOMMENDED SENSOR
AEM 30-2012

GAUGE PINOUTS
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Resistance A
PIN4: Resistance B
PIN5: Accessory ON (12V+ switched)

Gauge 4 - Oil Pressure

This gauge is designed to measure oil pressure and is identical in function in the black and white faced variants. It measures a voltage between 0 and 5 volts on pin4 to produce a corresponding oil pressure reading. It is only found on the Subarus and I believe there is also a black variant.

Unlike the oil temperature gauge which measures an analogue resistance from an unpowered temperature probe, this gauge measures a digital voltage signal from the oil pressure sensor, which is a powered sensor. The good news is there are less issues with calibration and matching a sensor. The bad news is there is extra technical work to install and wire the powered sensor which requires a stable 5V supply.

The main issue for this gauge is the OEM oil pressure sensor is no longer manufactured, and so an aftermarket one is required. The challenge was determining a viable option.

The AEM 30-2131-150 brass pressure sensor is an ideal match for the Lamco gauge, offering reliable pressure readings up to 150PSI with a stable digital voltage signal out. It does require a 5V supply voltage. The kits I provide have all the circuitry embedded to drive this sensor plug-and-play.

Reverse engineering the gauge secrets
In order to reverse engineer the Lamco pressure gauge I simulated the output from a pressure sensor using a laboratory power supply where I could set the voltage to any level needed. I discovered PIN4 was the signal pin through careful trial and error, and was then able to perform a similar experiment to the temp gauge, producing different gauge pressure readings by varying the input voltage, and measuring at each stage. I could then plot the calibration curve and match it to the output of an aftermarket sensor.

As you can see from my experimental results below, the AEM 30-2131-150 (150PSI pressure sensor) is a perfect match, resulting in 100% accuracy in oil pressure readings. I imagine many aftermarket oil pressure sensors would produce similar results, however AEM are my go to in terms of quality and value for money. For example, the DEFI oil pressure sensor is up to 400USD, whereas AEM's equivalent is around 80USD.

RECOMMENDED SENSOR
AEM 30-2131-150

GAUGE PINOUTS
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Not connected
PIN4: Sensor voltage 0-5V
PIN5: Accessory ON (12V+ switched)

Gauge 5 - Ambient temperature

This gauge measures ambient (outside) air temperature up to 50 degrees C. It is connected to an unpowered temperature probe (thermistor) that is mounted in the front bumper or on the intake airbox. I've never actually sighted this variant but the community informs me it can be found on the V2 555 STi's and is rumoured to work well with the OEM sensor that can still be obtained from Subaru. (See photos). If I come past any of the sensor or gauge hardware, I'll test it and post the calibration curves in this section.

Above: Subaru ambient air temp sensor that drives this gauge. Often found in front bumper or factory air box.

As I've not tested one of these gauges myself I cannot 100% verify the pinouts, but assume it is basically identical to the oil temp gauge, with 2 pins for resistance measured across pin3 and pin4.

GAUGE PINOUTS (assumed)
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Resistance A
PIN4: Resistance B
PIN5: Accessory ON (12V+ switched)

Installation - Mounting Gauges

Many Subaru enthusiasts want to install a triple gauge cluster in the OEM dash pod location, which looks awesome and is highly functional for the driver. The second main location is in a radio DIN location on the front console, which is standard for Mitsubishi setups. Either option works well.

Finding the parts takes perseverance or $$$
Bare gauge clusters can still be found in the 2nd hand market through Ebay, Forums and Facebook groups. If you're a determined buyer you will be able to track a set down and be prepared to pay between 200-500USD for a triple gauge setup as a ball park figure.

For Subaru owners, the Dash pod (pictured center above) is much more tricky to track down as these are also no longer manufactured. They are almost impossible to find on WRX's as they've mostly been pilfered, but a good trick is car wreckers and tracking down ~1997 Forester GTs (SF) that sometimes came with them as this is less known and there are still some kicking around.

Mounting dash gauge pod (Subaru GC/GF)
If you've managed to find yourself a gauge pod and want to install it on your 1992-2000 GC/GF Subaru, the good news is this is reasonably straight forward to do. You just need to remove the little compartment that sits there with a few careful cuts and you can get the dashpod installed with an OEM look. This is the way I mounted mine, and I have my build photos below to guide you through it.

Install Notes

Installation - Mounting Sensors

Where do the sensors actually mount? (Subaru)
The oil temp and oil pressure sensors must access a high pressure oil feed from the engine. This is inherently risky so care must be taken to install properly to avoid high pressure oil leaks. Ideally you want to mount into the oil gallery (often incorrectly called the oil galley) on the engine block, which is essentially a cavity that transfers the oil at high pressure immediately after it has left the oil pump, and distributes it throughout the engine. On Subarus, the oil gallery can be accessed from oil gallery ports, and there are a few options to choose from (see picture below).

It's also worth noting that if you have relocated your oil filter or installed a custom oil cooler,  there are often sensor ports pre drilled and capped on these units, which can also serve as a sensor mount location. A common example is a sandwich-plate adapter.

Above: The EJ series engine has multiple m18x1.5 ports to access the oil gallery, although most are inaccessible due to all the things bolted to the block for a running engine setup.

Below: The image below shows the two ideal ports to use: the factory oil pressure switch and an unused port on top of the block near the back of the engine (under turbo compressor outlet).

Above: Oil cooler and oil filter relocation kits have a sandwich plate that is inserted between the oil filter to add extra oil lines. These often have additional ports that can be used to mounts sensors (top right picture, see the small black cap with a hex fitting between the two large threaded female ports.

Sensor thread types explained - 1/8 NPT vs 1/8 PT vs 1/8 BSPT WTF???
In short: there are two common thread types for automotive oil sensors and this is based on the American standard or the Japanese/British standard. They are both taper threads and have the same taper angle with a 1/8 inch starting diameter BUT they have subtly different thread pitch and thread angles.

1/8 NPT
National Pipe Taper (American Standard)
This thread common to basically all USA made sensors, such as AEM.

Starting diameter: 1/8 inch
Thread pitch: 0.94082mm (distance between threads)
Threads per inch: 27
Thread angle: 60 degrees (angle between threads)
Taper angle: 47 degrees (the angle that the male thread grows at in diameter as it gets wider, measured against 90 degrees representing parallel thread)

1/8 PT or 1/8 BSPT
Pipe Taper or British Standard Pipe Taper (Japanese/British standard)

This thread is common to most Japanese and European sensors, such as DEFI.

Starting diameter: 1/8 inch
Thread pitch: 0.907mm (distance between threads)
Threads per inch: 28
Thread angle: 55 degrees (angle between threads)
Taper angle: 47 degrees (the angle that the male thread grows at in diameter as it gets wider, measured against 90 degrees representing parallel thread)

It's easy to get sensor threads wrong leading to oil leaks
As you can see from the specs above, the NPT and PT/BSPT thread types are very similar. In fact it's almost impossible to tell them apart with the naked eye if you compare two sensors next to each other of the different types because the taper angle is the same and the number of threads per inch is almost identical. It's so close that you can start bolting in a sensor to a mismatched female port and it will feel like it's working. It may work for a while but will likely lead to an oil leak because you will be stripping the sensor thread, which is often a softer metal like brass. After heat cycling and expansions and contraction of the metal, oil will find it's way through under pressure. Remember this is a high pressure oil line you are connecting to, unlike something like cam covers which capture oil spray, where a simple rubber seal will do the job of stopping a leak. More information on the thread types can be found in this resource.

Adapters are used to mount sensors into the oil gallery (Subaru)
In Subaru EJ series engines, the oil gallery ports are much larger than the sensor thread diameters, so adapters are used to physically mount the sensors. EJ engine oil ports are M18x1.5mm which is 18mm diameter port, with a 1.5mm thread pitch. This is a parallel thread (non-tapered). It's important to know the thread type of your oil sensor, so you can ensure you have the right adapter. Being a Japanese engine, the OEM adapter from Subaru has a 1/8PT (aka 1/8BSPT) sensor port. This will work for DEFI sensors but not AEM. For USA made AEM sensors you need an aftermarket oil gallery adapter (which I supply in my kit)

Above: these diagrams show how the sensors physically mount into the Subaru EJ series engine. Left shows the OEM oil pressure switch mounted in the OEM oil gallery plug (part 11024AA210). This plug is compatible with Japanese sensors like DEFI. On the right I show the setup required for using USA made sensors, such as AEM. These require an aftermarket adapter plug with a 1/8NPT thread.

What's the best mount configuration? (Subaru)
I've experimented with multiple options, including trying to dual mount sensors on a single oil gallery port to save time and effort, but the reality is with the EJ engine series, there is limited clearance to use a T-Piece or V-piece to dual mount sensors, especially as the oil pressure sensor is quite bulky. As a result, you do really need to mount each sensor in it's own dedicated oil gallery port.

Recommendation:
1. Mount oil pressure sensor in OEM oil pressure switch location (i.e. replace the OEM oil pressure sensor)
2. Mount oil temp sensor in spare oil gallery port under turbo compressor outlet (See engine diagram below))

Above: recommended AEM sensor locations for Subaru EJ engine series, showing oil pressure and oil temperature mount locations.

Installation - AEM Oil Pressure Sensor (Subaru)

Installing AEM 30-2131-150
I recommend replacing the factory oil pressure switch (OEM Sensor), which is mounted on an oil gallery port immediately under the alternator (alternator must be removed to access). This is an optimal location to measure oil pressure. The trade off is by removing the oil pressure switch (which is an on/off sensor) the red low-oil-warning light on the dash will stay permanently off. I can supply a custom electronic circuit in my kit that will mimic the output of the OEM sensor when the oil pressure is low, and retain the low oil warning light condition. You simply remove the OEM sensor, install the adapter and AEM sensor, and I have an extra wire that connects to the engine bay plug that the factory sensor connects to, retaining the dash warning light functionality.

Above: The OEM oil pressure switch is located under the alternator (which must be removed). This can be removed along with the OEM adapter plug, and an aftermarket adapter and sensor can be installed. Note the AEM unit is much more bulky and taller than the OEM unit, but there is enough clearance to reinstall the alternator above it and squeeze the plug on when ready.

Installation Steps

Installation - AEM Oil Temp Sensor (Subaru)

Installing AEM 30-2012
Unlike the recommended oil pressure setup, where we are replacing the OEM sensor with the AEM unit on an existing oil gallery port, the temperature sensor is an additional sensor that must go into the engine block. I recommend using the unused oil gallery port which is located immediately under the turbo compressor outlet (you need to remove the top mount intercooler and throttle body, plus a bunch of hoses to access properly). Be warned, this is a bit of a bastard and took me a good few hours of fiddling.

Above: These images show the exposed oil gallery port after the cap has been removed (left) and the installed AEM adapter and sensor (right). Note all the removed hoses and throttle body to gain good clearance to work. It's a bastard but doable DIY.

Installation Steps

Installation - Wiring in Sensors

With the sensors and gauges installed the final step is to wire everything up

Some gauges sets come with plugs and wiring which can potentially be repurposed but ultimately when running custom sensors you need to build a new custom harness to link the sensors to the gauges, and supply power. All the information needed to do this DIY is in this guide. I've spent 12 months experimenting with different options to produce the plug-and-play kits.

The Lamco gauges require a 12V supply to function, and for the backlight operation. All gauges have 5 electrical pins on the back face, except the boost/vac which have 2 pins only. Details of what each of these pins are provided in the dedicated sections above for each gauge, but have been provided again below.

GAUGE PINOUTS: Voltage
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Not connected
PIN4: Not connected
PIN5: Accessory ON (12V+ switched)

GAUGE PINOUTS: Oil Temp
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Resistance A
PIN4: Resistance B
PIN5: Accessory ON (12V+ switched)

GAUGE PINOUTS: Ambient air temp
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Resistance A
PIN4: Resistance B
PIN5: Accessory ON (12V+ switched)

GAUGE PINOUTS: Oil Pressure
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)
PIN3: Not connected
PIN4: Sensor voltage 0-5V
PIN5: Accessory ON (12V+ switched)

GAUGE PINOUTS: Boost/VAC
PIN1: Ground
PIN2: Headlight ON for backlight (12V+ switched)

Gauge pins are dupont type
The Lamco gauge pins themselves conform to the electronics PCB standard of 2.54mm between each pin. This means the standardised dupont type plugs will work. These are what I use.

Powering up gauges from radio harness
The gauges need three external sources to run: 12V+ switched accessory ON, ground and headlight ON (12V+ switched) for the backlights. These can most easily be taken from the radio harness on Subaru's, which has everything you need. A multimeter is required in order to identify and verify you have the correct wires, but be careful because the radio harness has a constant 12V (usually yellow) which you do not want, as this will drain the battery even with the ignition off.

Accessory ON (switched 12V+): this is usually a red wire on GC/GF series Subaru radio harness. Verify it with a multimeter, it should only read 12V when ignition is set to accessory or ON.

Ground: usually a black wire on the radio harness

Headlight ON: this is usually green or purple on the radio harness. Verify with multimeter. It should only be 12V when the headlights are ON.

Sensor wiring and plugs
The sensors are exposed to heat temperature and vibration being bolted directly to the block, so decent automotive wiring is recommended, with heat shielding sheath. If purchasing sensors direct, they ship with plugs and dupont style pins which need to be crimped. This is fiddly and really easy to get wrong. A bad crimp will lead to the sensor wire popping out the plug once it's seated. I use a top end crimper tool to do this properly, wiring in each sensor plug with fibre glass heat shield rated to 650 degrees (see photo gallery for more snaps).

Above: Lamco gauge pins conform to the dupont 2.54mm pin spacing, which are pretty available and can be crimped (left). The sensor plugs use larger size dupont style connectors which must be crimped and seated. This are tricky to get right as they don't come with spare connectors if you have a bad crimp.

Routing sensor wire through firewall (right hand drive vehicle)
All pretty self explanatory, but a few tips for running the sensor wire into the cabin from the engine bay. I routed it to the side of the engine bay near a suspension strut as lots of existing engine bay wiring is here which is easy to attach to. I then go through the rubber grommet to the right of the brake master cylinder (this is on a right hand drive vehicle.)

This pops the wire out behind the driver's clutch pedal, and it can be run up behind the front console.

Above: The terribly drawn line and labelling show the basic path I've used to route my sensor wiring through the engine bay. These show the working setup, with the black braided heat shielding for each main sensor (temp and pressure).

Maintenance

How to replace backlights
If you have a backlight failure, worry not, the bulbs are inexpensive, easily replaceable and fairly easy to access.
On the back of each gauge there is small squarish plastic protrusion sticking out. This is the bulb mount.
Remove this piece by gently pushing and turning it about a quarter turn counter clock-wise
The whole piece should then pop out and inside it, you should see a tiny incandescent bulb which is clipped in
Remove the bulb by pulling it out directly. They are usually pretty tight in there so if hands won't do it, be very gentle with pliers as the bulb is glass.
The bulbs often have a coloured rubber condom on them to provide a hue, such as green glow. You an gently remove this and put it onto the new bulb.
Jam the replacement bulb back in and screw the backplate back into the main gauge housing.

What type of bulbs are required?
The OEM style incandescent bulb is a 2 watt T5. Search "2W T5" on google and you can find them usually in packs of 10 from ebay, ali express etc. Motorcycle shops also often stock them as they are a standard. E.g. Honda service and parts places.

What about coloured LEDs and brighter bulbs?
Some people upgrade the bulbs to LED variants that have the same formfactor as the T5, but output much more light. Search "T5 LED bright" or something and you will find some options. Note you can easily go too bright with these and I recommed against it. Stick to the nice OEM incandescents if you are unsure. This is a way to change the colour though quite easily, especially if you have a custom installation and want to colour match to your main instrument cluster on the steering wheel.

Above: 2 watt T5 incandescent globes (left) and bright LED aftermarket types (right)