narrow / wide band question

[BrandonW]

a buddy of mine told me not to use a wideband and that i should use a narrow band he said they were useless for boost which i don't believe, it was to my understanding that the wideband was the better choice for a tune and for daily use

if you guys need anymore info i can let you know

my goal is 350hp to the wheels but not right away, i should be at about 300hp to the wheels right away

mods: full 3in exhaust turbo back, intake, hardpipes, 57trim ct26, .020 over pistions

 

[jetjock]

Your buddy is clueless. Although a NB can be used for WOT (us old school types did it all the time before WBs were available) it has limitations a WB does not. The NB is better for closed loop use however.

 

[BrandonW]

this might be a bad question but what exactly do you mean by closed loop, i think i know what you mean but i want to be sure

 

[NewWestSupras]

The OEM closed loop operating mode relies on the narrow band oxygen sensors signal. It's aim is to keep the air fuel ratio at 14.7:1 at idle, under normal "steady state" circumstances ie cruising on the highway. This is my "narrow band" understanding of it, btw.

 

[jetjock]

^ Correct. The engine is operating in closed loop during any steady state condition except when it's cold or at WOT. In closed loop the O2 sensor is trimming the fuel mixture in an attempt to always deliver a stoichiometric exhaust stream to the catalytic converter. Stoichiometry is the theoretical mixture where all the fuel and all the oxygen is consumed. In theory it leaves behind nothing but water vapor and carbon dioxide. In practice it's never quite that good, hence the "need" for a catalyst.

 

[BrandonW]

hmm so would it be wrong to use it for a tune and then daily driving? (except to keep and eye on things if doing a pull or something)

and im referring to the aem wb

 

[NewWestSupras]

As the w/b is basically used for tuning, that's the wtg. Since the n/b o2 sensor doesn't have logging capabilities afaik, the wideband is generally used in conjunction with an Afpr to tune. gl.

 

[jetjock]

The signals of a NB and WB are different but your WB controller will emulate a NB signal. You'll have to connect it to the ECU in order for it to do closed loop duty. I'm not a fan of this for other reasons but none that will make the engine run differently and people do it all the time.

 

[BrandonW]

oh ok thanks for the info, i do plan on doing the lex afm injectors and such later so maybe it will be more handy then

what narrow bands are out there i haven't seen any, but maybe this is because i haven't looked, any ones recommended?

 

[jetjock]

Look under your hood

 

[87M-GTE]

Yeah, your buddy has no idea what he is talking about, just do it right the first time and get a wide band..it will make for a worthwhile mod, one that you won't have to replace or upgrade later.

-Sam

 

[BrandonW]

oh haha i was talking about a gauge but i guess that would just be a light show so nevermind

reason i asked this question is because i already have a wb but i might return it if possible since i don't need it at this point, or i could just put in on (the ddp i have has bung for it but this might be useless and i don't know if its that easy)

but i may need it down the line when i go a little further with my mods

 

[87M-GTE]

definately keep it, you for sure will be needing it down the line if you plan on continuing to modify your car.
As for the gauge, a WB gauge gives you the exact A/F ratio, where as the NB gauge gives you colors with the categories of rich, lean and stoich

 

[crisp]

My narrowband is right under my large readout wideband. (Powerdex/AFX)

From a "layperson" perspective, knowing that both are giving me "feedback" of some nature, the narrowband amounts to mostly a "light show" and the wideband is a much more functional tool that shows me the relative air-fuel ratio under various conditions in a much more accurate manner. The key appears to be not only to know the air-fuel you are achieving in any given state, but to further know what is the "target" within those states.

i.e.: If I am under full load on boost, I am wanting a RICHER tendency to be "safe", perhaps in the 10's or 11's, even though that's richer than stoich. When I am under deceleration or light load, I am more comfortable with a leaner mix in the 13's and 14's for example. (Not to mention these are references for GASOLINE, and different fuels operate optimally at different ratios...)

Cruising or idling, you often don't want to be too rich, as it's just blowing a lot of stinky into the air... and wasting fuel to boot, etc...


As I understand it, being in the 12's is often the power target, but as you can see above, it's not always the rule depending on your operating state and type of engine, boosted or non being distinctly different in what they "want" to see, hence needing differing settings, or targets. The wideband can help you monitor these specific ratios as a metric, and the narrowband is just giving you a "broad range" represented between, say, 11 and 13 as "STOICH" for example (there are specific values to what is considered "stoich"... perhaps another member can elaborate, as these are reference values for the concept as I understand it...) but such nb units are, as mentioned before, only accurate within the "LEAN/STOICH/RICH" ranges under CERTAIN STATES, such as FULL LOAD/WOT or IDLE. Not very helpful when it's mostly bouncing around the rest of the time.



I welcome any/all corrections, as I'd prefer to understand than defend my very limited understanding of this newly acquired and exercised set of instruments in the WB and NB. I am particularly interested in and fascinated by the subtle and complex relationships between especially the EGT (Exhaust Gas Temperature) gage readings and air-fuel monitor readings in varied conditions. Lots of stuff going on there when you start to play with ignition and cam timing, too.




-crisp

 

[jetjock]

I dunno but I'll say one thing: Your tendency towards prolixity exceeds even mine

 

[BrandonW]

ok so just hold on to it for down the line, i can still use it as a gauge when not tuning for doing a pull or a possible ride down to the track just to keep a eye on things but for cruising on the highway its not really useful correct me if im wrong

the other bung in my dp is pretty close to where the stock o2 is so that might be a bad thing for the aem sensor which i think in one thread is a bosch unit

 

[crisp]

I dunno but I'll say one thing: Your tendency towards prolixity exceeds even mine

think?





(Wish I had the "expertise" that you and others are able to exercise on such matters... but I am trying carefully to listen to what I hear from the prolific and purposeful among the wiser and tenured amongst us in here, or otherwise endowed...)


immitigably verbose, yes.




-crisp

 

[crisp]

ok so just hold on to it for down the line, i can still use it as a gauge when not tuning for doing a pull or a possible ride down to the track just to keep a eye on things but for cruising on the highway its not really useful correct me if im wrong

the other bung in my dp is pretty close to where the stock o2 is so that might be a bad thing for the aem sensor which i think in one thread is a bosch unit

I think you have the two backwards? Did you say you have a WB or a NB?


If WB, DEFINITELY keep and USE IT right away, just to learn the behavior of your car...


...if it's the NB, I kept mine because it was "laying around" in a box, new, and I had it in before I got the WB AFX. With the AFX, I've never once needed to look at the NB, but it makes for some colorful dynamics... a double-edged-sword, depending on your preference.


-crisp

 

[BrandonW]

i have the aem wideband

 

[crisp]

i have the aem wideband

Keep it.




-crisp