What's the difference in readings between a narrow band and AEM wideband gauge.

I am getting a Vortech SC next week and was looking into the gauges needed. I like the Defi D-gauges set to American readings, ie 20psi boost gauge ocer the 2 bar gauge. Anyway, they hav an A/F gauge as well but I am pretty sure it's a narrow band.

 

I don't know the technical difference but I do know that everyone who knows about F/I recommends a wide band. When I see the words "narrow band" used it has often been followed by the word: WORTHLESS.

 

a wideband uses a different o2 sensor compared to your stock. it has 5 pins instead of four this allows it to read a larger range of af mixtures. the most popular one on the board the aem uego can read between 11:1-17? whereas a narrowband may only read a smaller area between that and the wideband is said to be accurate to .1 of an af. a narrowband may not be as precise ( i dont know what the tolerance is)

 

The narrowband 02 sensor is the same type as your factory O2 sensory. It is only designed to read just around the 14.7:1 or leaner. Once you go richer than about 14:1, they arent calibrated to read A/F mixtures that rich....so yes...they are worthless for F/I...or N/A for that matter. See...I waited a while before using the word "worthless".

These types of o2 sensors are simply designed for emmissions purposes, and when the sensor says "hey...you are running too rich", the ECU will comepensate until it gets back to 14.7:1. It doesnt really care HOW rich...just that it is rich, and needs to get back to stoich.

The AEM guage style wideband that many folks have can display A/F ratios between 11:1 to 17:1, but if you plan on logging it to the Profec or other engine management system, the sensor is actually calibrated from about 9.7:1 to 19:1.

 

So what purpose would a narrow band A/F gauge serve? I don't plan on doing any tuning. I'll leave that for my tuner. It's a SC so the boost will be set and that A/F ratio will be set. Not many changes I can do. If I need something changed I'll take it back to him. I understand that tuning needs to get done after every major mod but I already have headers, race pipes, and exhaust so I don't see any tuning changes in the near future. And I believe that a wideband O2 is used when they tune the car on the dyno. I would just like to know if I start running lean or rich. Would a narrow band A/F not tell me that?

 

That narrow band will tell you that you are lean...but not really how lean..or how rich. Think of it like a 3 part switch. Lean, Rich, or 14.7:1. That is essentially how to look at it.

Even with proper tuning, many people still run full-time widebands in their car due to the variations in the ECU programming. Depending on the ambient conditions. engine load, and numerous other variables, you may be running richer or leaner than your dyno tuning runs would indicate.

In my opinion, wide-band A/F is a must have device with F/I. Some will disagree with me, but there is great piece of mind when going WOT, and taking a quick scan at the digits on the wideband to insure you REALLY are sufficiently rich.

 

Yeah! See! Like he said!

 

Thanks you guys, I appreciate your prompt responses.