Review on Equus 8366 Ratio Gauge Aluminum by Jay Arnold

First, Revain's product description was incorrect. They advertised it as a blackface fuel pressure gauge. What you see is what was sent: a dual air/fuel ratio sensor with a white face. Technical: 1. Equus technical phone support was marginal at best. The representative did not appear to be convinced of the expertise or the information he was presenting. The bottom line is, don't expect "technical" help from Equus.2. The pressure gauge and LED display are excellent and easy to connect/install. There are no hidden issues here, the LEDs are bright and easy to see, and the display responds quickly to O2.3 input with no lag. The product manual completely lacks a useful interpretation of the presentation. That is, what does the information displayed on the pressure gauge actually mean? Depending on the engine; type of O2 sensors; location of O2 sensors; and regardless of whether it is an injection or a carburetor engine, all this leads to different characteristics of the readings of the sensors. For example, in my application, the gauge shows "optimal" readings at cruising settings, but the entire display disappears completely when full throttle (carburetor) is selected. I have yet to determine if this is normal sensor response or limitations of the O2 sensor. The engine runs fine/strong at full throttle with all the signs of a proper air/fuel mixture, so why is the gauge completely blank? It would be nice if Equus Technical Support could provide an answer, but this limitation has already been identified. All in all, this is a very good device for "horny gimmicks", but I can't recommend it for realistic tuning. Tool until the cause of the complete lack of signal at full load is eliminated.