Defi A/F Gauge Install

[atgotianse]

Hey guys, I wanted to ask if anyone knew how to install the A/F gauge from Defi-Dgauge? It didn't come with an O2 sensor and says I have to purchase one. Can I not tap the current O2 sensors after turbine or in the exhaust line after the cat? If you any of you had experience installing this gauge, any information would be great. Thanks

[Airgiod]

i seem to remember reading something about the stock sensor not giving good reading to a guage...something about a limited output voltage range.

[MarkSAE]

The stock o2 sensors are narrowband, meaning they are only accurate reading A/F ratios around stoic, 14.7:1. This is good for closed loop driving as this is the target a/f ratio our ECU shoots for while we're just cruising around.

At WOT, our A/F's richen up significantly. I believe stock A/F's at WOT are around 9.5:1. when tuned, turbo cars seem to make the most power between 11:1 and 12:1 depending on octane and safety margin. Either way, this is out of the accuracy range of the stock sensor.

This is why people want a wideband. A wideband can accurately read A/F ratios from 10:1 all the way to 20:1.

[atgotianse]

So a wide band o2 sensor is needed? Do you know of a particular brand that is good which I can hook up my gauge too? And where do most people install this sensor? After turbine, after cat? Thanks for the valuable input.

[MarkSAE]

I believe your gauge is designed to work with OE narrowband sensors. If there was a wideband available, it would have been an option for you to purchase. I'm sorry to say that you purchased a pretty gauge that doesn't serve much of a function. All it tells you is whether or not your o2 sensor is working.

There are plenty of wideband o2 sensor kit choices available on the market. Zeitronix is really good and reasonably priced. AEM has a gauge that uses a wideband. There are a few others.

[atgotianse]

Thanks for the feedback. After I read the instructions manual, I kind of figured out it would be a big hassle to install it. My friends Evo runs a motec with the same gauge and it works real well for tuning purposes. Thanks again