VEMS EAW-52 Round dual-display gauge ( 52mm WBo2 + EGT meter with lotsof extras )

Pinouts [here] eg. [WBO2 wire-colors] with new wire-colors on page1, old colors on page2 (trivial to tell which one applies).


[Purchase Roundv1_WBO2_EGT here]



[Purchase Roundv2_WBO2_EGT here]


Firmware Releases

[VemsTune] is required for round firmware upgrade and operation for both the Aim and Non-Aim firmware.

Stable releases:

For testing only:

Firmware features

Since this is meant as an easy-to-use device, first only very few features are supported.

New features supported since 2010-03-29 firmware

Display features

Related Software


Warning: the WBO2 sensor in the exhaust is ruined quickly if not heated. When the engine is running, keep the controller running too (so it keeps the sensor heated) or remove the sensor from the exhaust (and use a M18x1.5 mm plug).


Allows mounting even with the tightest available space:



U-bracket mounting bracket:


The simple factory "harness" (with the DSUB15 female) only has supply wires and a fuse:

To connect for the WBO2 and EGT functionality is trivial (including datalogging with PC). The RPM input and voltage output has some options, detailed below (these functions are rarely used, but sometimes very useful).

The manufactured version features:

Free air calibration

The RCal resistor in the sensor is supported, so calibration is not necessary. The optimal PID parameters are different in the exhaust stream and free air, so don't worry if free air reading is slightly off or even floating somewhat. Note that toleration in the lambda range is very good: 5% error means (actual => reading) 0.8 => 0.81 lambda (since the difference from lambda=1.0 counts, which is 0.2 and 0.19 respectively).

Connector Pinouts

RS232 - DSUB9 female. Note that any extension cable needs to be straight through and not cross-over.

Main connector - DSUB15 male.

On Round V1 (serial number < 3000) 5 pins (pin 2,3,4,5 and 7) of the DSUB15 are NOT connected


On Round V2 (serial number > 3000)


More printable user-guides are at: