Wide band O2 vs narrow(?) band O2 sensor?

clutchdust

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I'm putting A/F gauges in all my carburated cars because it seems to make them a boatload easier to tune. I'm seeing meters in the catalogs with a huge step in price. The conventional narrow (I'm guessing it's narrow since the other one is "wide" band) seem to run between $50-80 for a gauge. Meanwhile the ones advertised as "wide band" look to run in the $200-300 range. Someone please 'splain the difference to me.
 
I don't know WHY they do it this way, but the explanation runs along lines of the narrow band/stock O2 sensors are like a switch, keeping a knee action, for holding the 14.7-1 A/F ratio....so the computer just adds and subracts a certain amount to react with the sensor.....

Now if I designed a sytem, I would want one programmed to use a wide band sensor which will detect between ~12-1 out to ~18-1 A/F ratio.....so the wide band one is what is necessary for tuning most setups, once in the ballpark, around 14.7 the computer knows WTF from there from the program....

years ago there was a guy named Norval, who got his computers to run with a wide band and he would pull it out to 17-1 ratio....lean as hell, he was in Canada at the time, as I recall......so I dunno about EPA and shit up there, much less it was a old shark, of course....

:gurney:
 
Narrow band is only useful to an ecu. It only monitirs if you're outside an ideal A/F ratio mix, then adjusts the injector cycle to more or less.
With a carb, you need a wide band to tune.
 
Narrow band is only useful to an ecu. It only monitirs if you're outside an ideal A/F ratio mix, then adjusts the injector cycle to more or less.
With a carb, you need a wide band to tune.

True, but the mystery to ME is why not use a WB sensor and teach the computer to deal with it....??

:shocking:
 
GM only builds what's needed, not wahat's useful......Unless it's some pointless gimic like Onstar, automated parallel parking, or extra cup holders.
Narrow band is only useful to an ecu. It only monitirs if you're outside an ideal A/F ratio mix, then adjusts the injector cycle to more or less.
With a carb, you need a wide band to tune.

True, but the mystery to ME is why not use a WB sensor and teach the computer to deal with it....??

:shocking:
 
True, but the mystery to ME is why not use a WB sensor and teach the computer to deal with it....??

You definitely have your moments of genius. I was just thinking about that the other day. For maxumum acceleration the af should be somewhere richer than 14.7 but how can the computer maintain anything but 14.7 if it can only measure at that balance point? I would think a wideband would be an enhancement to modern fuel injection.

I still haven't got around to putting my LM-1 WB meter in. The wife has been busting my balls to do all the yardwork.
 
True, but the mystery to ME is why not use a WB sensor and teach the computer to deal with it....??

You definitely have your moments of genius. I was just thinking about that the other day. For maxumum acceleration the af should be somewhere richer than 14.7 but how can the computer maintain anything but 14.7 if it can only measure at that balance point? I would think a wideband would be an enhancement to modern fuel injection.

I still haven't got around to putting my LM-1 WB meter in. The wife has been busting my balls to do all the yardwork.

Here's my thoughts on the subject.
1) Narrowband O2 sensors are damn cheap, stone reliable, and do the required job for the OEM people (low emissions and good fuel economy). WBO2 sensors are stinking expensive, and I hear too many unfavorable stories about their durability. (Be gentle with your LM-1!)
2) WBO2 sensors aren't necessary (neat to have, but not necessary) in most production cars. The narrow band sensors will tell you when you are at stoichiometric A/F (14.7), and the ECM knows/stores the pulsewidth that delivers this correct 14.7 A/F ratio (along with all the correction factors from the system variables such as system voltage, pump pressure, injector tolerances, etc) so it's a pretty easy function for the software to just multiply the pulse width by the ratio of the A/F enrichment desired. If you want 12.5 A/F ratio just multiply the 14.7 A/F ratio pulsewidth by 1.176.
 
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OK, so you guys have not sufficiently explained to the dumbass in the corner (me) what information a wide band sensor gives that a narrow band does not.
 
OK, so you guys have not sufficiently explained to the dumbass in the corner (me) what information a wide band sensor gives that a narrow band does not.

Clutch, try reading this article paying special attention to the graph that shows the voltage output of each type of o2 sensor. i.e. wideband and narrow band. you will notice that the narrow band sensor only has three voltage states (lean, stoc, rich) where as the wideband is a linear plot of voltage vs A/F. Much more useful and accurate for tuning. The ecu has to search for stoic using narrow band, bouncing high and low when it finds it. I then applies a percentage multiplier to move injectors to other A/F settings based on your fuel tuning map

http://www.enginebasics.com/EFI%20Tuning/AF%20Ratio%20Basics.html
 
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[ so it's a pretty easy function for the software to just multiply the pulse width by the ratio of the A/F enrichment desired. If you want 12.5 A/F ratio just multiply the 14.7 A/F ratio pulsewidth by 1.176.

Easy but you are really in open loop mode. Some assumptions are made.

Or we could forget A/F ratio and adjust fuel under heavy throttle based upon an on board accelerometer?
 
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Ok try this, narrow band is a little like being married......
If everything is perfect, you're ok. Once you step outta line a little bit in any direction, the sensor (wife) starts screaming at the ecu (you).

OK, so you guys have not sufficiently explained to the dumbass in the corner (me) what information a wide band sensor gives that a narrow band does not.
 
MY question is, can I get better fuel economy by reducing the LBS rating of the injectors....I have #24 in there now......if I replace with 21's with the milder cam....can I get better economy, I told the chip guy I had 24's....so can the computer get along with the change? ...

:hissyfit::drink:
 
MY question is, can I get better fuel economy by reducing the LBS rating of the injectors....I have #24 in there now......if I replace with 21's with the milder cam....can I get better economy, I told the chip guy I had 24's....so can the computer get along with the change? ...

:hissyfit::drink:

In a word, NO. It's like pouring a 12 ounce coke can into a 12 ounce glass, or pouring it into a 16 ounce glass. The appearance is different (glass size or injector pulsewidth), but the fluid content is the same each time it's poured.

The ECM would just increase the injector pulsewidth to compensate for the reduced flowrate of the smaller injector.
 
Narrow band O2 sensors can only "see" from about 13:1 to about 15:1. They do this over a 0-1 volt range and the raw data can be read with a DVOM. A wideband O2 sensor has a range of 10:1 to 20:1 over 5 volts but requires a circuit board to decode the sensor data. A widebands better and more linear resolution not only allows you to target a very precise AF ratio but helps you get there.

Rob
 
OK, so in my application where there is no computer involved, I'm just using an O2 sensor and A/F meter as a tuning aid, there is no noticeable advantage to wide vs narrow band?
 
OK, so in my application where there is no computer involved, I'm just using an O2 sensor and A/F meter as a tuning aid, there is no noticeable advantage to wide vs narrow band?

Think about it as having a green light for rich and a red light for lean. The light is only ever going to be red or green.

That doesn't give you a lot of help when tuning.
 
Not sure which meter you're looking at. Or maybe the meter I'm using is a bit more gimicky... don't know. But the meters I use have a "full sweep". Looks like THIS
 
Not sure which meter you're looking at. Or maybe the meter I'm using is a bit more gimicky... don't know. But the meters I use have a "full sweep". Looks like THIS

I guess you're asking me in response to my post.

Ok then, think about the meter only ever being pegged left or right and only swinging back and forth past 14.7
 
Been reading this thread again, and so I have to ask, that if I had a O2 sensor on a carb engine, I could plug that into a DVM and read the voltage, that would say lean or rich, same as if it was talking to a computer....that should get any tuning within range fairly easy, I would think.....if it's say lean, when running on primaries, light throttle I would imagine it would stay there until the carb was enriched and if enriched too much, it would swing the other way and so to back off a bit....

I fail to see why it would not work for a street machine, true a race machine is outta the range, but for economy street tuning, why not??

:shocking:
 
Not sure which meter you're looking at. Or maybe the meter I'm using is a bit more gimicky... don't know. But the meters I use have a "full sweep". Looks like THIS

Clutch, that is a wideband O2 sensor and meter! That is exactly what you need and should get. A narrow band sensor will not work with that meter. You can :banghead: to your hearts content mechanicly tuning that carb with this meter.
 
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