Big topic if we go into detail...but
Very simply, A typical narrow band sensor outputs a signal corrosponding to the lambda value of the exhaust gas, however it will only tell you if the gas is above or below lambda 1, with very little useful indication of the specific Lambda value. It can be viewed as a switch, outputing information indicating a Lean (> Lambda 1.0) or Rich (< Lambda 1.0) mixture.
Generally this sensor is found on older vehilcles, newer vehilces which are aiming for better emmisions, power etc... tend to use Wide Band.
There are lots of different wide band sensors but excluding the different technologies, a wide band sensor will output a signal that is accuratly related to the actual specific Lambda Value of the exhaust gas. So you know how Lean or Rich you actually are. So for example your ECU knows you are at 0.82 Lambda ( not just rich, as with a narrow band). This more detailed information allow the ECU to make better decisions.
For Race and performance tuning, wide band is the only real option.
>MoTeC's older ECU's and Early ADLs used the Bosch LS11 ( If I remember
)
>MoTeC Newer ECU's (M800 etc...) typically use the Bosch LSU4 range.
>The PLM (motec lambda meter) uses the Bosch LSU4 or the NTK UEGO ( can it use the UEGO sensor straight out of the box?? )
I'll let others argue over the pros and cons of Bosch V NTK.......I've already made my choice
John.