wideband

[jetjock]

Nicely done jimi. I remind everyone of the obvious though: An O2 sensor, WB or not, is only capable of measuring one thing: oxygen. And while there is a correlation between O2 and A/F there are several things that can goof it up. Leaks in the exhaust system for example. Since an O2 sensor doesn't give all the facts you should have the car initially tuned using an NDIR anaylzer.

mkiii: No, you can't connect a cheapie A/F gauge to a WB (if I understand your question correctly) unless the WB's controller has an output that mimicks a NB's signal.

 

[mkiii88supra]

well i have a Autometer cobalt full electric one so couldnt i just adapt it somehow to the wideband?

 

[jimi87-t]

alright so basically a wideband is just better for tuning and monitoring purposes. so if i have an a/f gauge already i just need the actual wideband and i can use my gauge to monitor it correct?

can you go without using a wideband?

1)No you also need the controller to be able to read the wide band. The LM-1 has the ability to send a signal to a narrow band gauge for proper read out. But that means you still need the wideband sensor and the controller.

2) If you are tuning, no. If you are stock or there about, yes.

I remind everyone of the obvious though: An O2 sensor, WB or not, is only capable of measuring one thing: oxygen. And while there is a correlation between O2 and A/F there are several things that can goof it up. Leaks in the exhaust system for example.

Yep, this and other factors is why I do not use the the option from the LM-1 to send the ECU a stock type signal. Also this is why if you have a bad plug or improper burn, it will show up as a lean condition when you are actually rich.

(more info for those searching)

Ok, with the above carts. You can see that a narrow band only shows if you are above, at, or below Stoich. Seeing as we do not tune for Stoich (unless you like turning your internals into metallic soup) We tune for a richer AF ratio, a narrow band has no way to display how rich you are and you will just end up chasing your tail. So an AF gauge that reads your stock sensor is useless, sorry.

 

[Joel W.]

so is that lm-1 really that easy to use jimi? im no rocket smartguy, but that logworks proggie looked pretty straight forward?

 

[mkiii88supra]

so i would need to get a whole wideband kit with everything and it would let me use the gauge i have now correct? and the wideband it definitely needed for correct tuning purposes? so with a wideband controller that is supposed to control air and fuel what is the point of having a SAFC?

 

[jetjock]

Again jimi, well said. The entire point is to tune for a best power mixture at WOT. As a point of interest the ecu uses the stock sensor only during steady state conditions. It's ignored during cold idle, WOT, and during accel and decel. In fact you'd be surprised at how often the O2 sensor on your engine isn't "in the loop".

Mkiii, you seem to be missing the point. The WB's signal is not compatible with a NB A/F meter and can only measure stoich. You can get one to operate your meter if it mimicks a NB's signal (the LM-1 does this). Not only is the WB's output linear but it's reversed. Nor does it "control" the A/F mixture (unless you connect it to the ecu, not recommended). It's normally used strictly as a monitor for WOT mixture.

 

[jimi87-t]

so is that lm-1 really that easy to use jimi? im no rocket smartguy, but that logworks proggie looked pretty straight forward?

Yes, it is pretty straight forward, I have not started tuning with it yet, but it did save my motor the first time I started it up by showing me I was way lean.

so i would need to get a whole wideband kit with everything and it would let me use the gauge i have now correct? and the wideband it definitely needed for correct tuning purposes? so with a wideband controller that is supposed to control air and fuel what is the point of having a SAFC?

1) yes, more info can be found about that on their site.

2)Yes, a must.

3)No, it does not control the tuning on the ecu, you use it to show you how the SAFC or other device needs to be programmed.

 

[jimi87-t]

Again jimi, well said. The entire point is to tune for a best power mixture at WOT. As a point of interest the ecu uses the stock sensor only during steady state conditions. It's ignored during cold idle, WOT, and during accel and decel. In fact you'd be surprised at how often the O2 sensor on your engine isn't "in the loop".

Mkiii, you seem to be missing the point. The WB's signal is not compatible with a NB A/F meter, NB can only measure stoich. You can get one to operate your meter if it mimicks a NB's signal (the LM-1 does this). Not only is the WB's output linear but it's reversed. Nor does it "control" the A/F mixture (unless you connect it to the ecu, not recommended). It's normally used strictly as a monitor for WOT mixture.

Yep!

(Fixed it.)

 

[mkiii88supra]

i was just confused i guess. so the wideband has nothing to do with an AFC tuning your a/f ratio it just monitors the a/f ratio. is this correct? so is there even a real purpose to having a regular a/f gauge?

 

[jetjock]

Ugh....I implied a WB's signal can only measure stoich. Bad writing there

Mkiii: You got it. A normal A/F meter isn't any good for tuning but it's far from a total loss.
It tells you at a glance the O2 sensor is cross counting and the entire lambda trim loop is working. It proves the ecu is making corrections to the mixture on the fly. It doesn't prove the mixture is right but is proves the loop is alive. That's good info to have because a lot of stuff has to be working to have it occur.

You could easily get the same info from the diag block in the car but a NB A/F meter provides it all the time. Fwiw my Supra (and my other cars) all have them connected to the stock sensors to serve as quickie diagnostic devices.

 

[jimi87-t]

i was just confused i guess. so the wideband has nothing to do with an AFC tuning your a/f ratio it just monitors the a/f ratio. is this correct? so is there even a real purpose to having a regular a/f gauge?

1) yep, when tuning you are the "brain", and it is now in your hands to make sure it is running right
Just like a temp gauge shows what temp you are at, it can not change it. It is up to you to make the changes.

2) not really

 

[mkiii88supra]

so basically im thinking about sending back my a/f gauge and using that money to go towards a wideband. thanks guys for all the help.

what would the a/f gauge do for me.

 

[jimi87-t]

Thats what SM is here for! :biglaugh:

The one you have (NB)? Like JJ said, to keep an eye on your stock sensor to see if it is switching, but if you are at the point where you need a WB, then the WB will keep an eye on it and there will be no need for the NB gauge.

 

[IJ.]

Gay self quote:

The WB will show a lean condition but during a hard pull the damage will already be done by the time your brain registers it....

They're just a gauge/tool and I'm not sure I'd trust one to handle the tune/adjust it anyway as they're not 100% reliable even under ideal conditions.

 

[mkiii88supra]

where does the switch begin from using ur stock o2 to having to upgrade to a wideband?

 

[souprat]

when you want to tune past fuel cut(when you have fuel mods). when you get some kind of tuning device.

 

[IJ.]

There isn't one...

The narrow band 02 is performing a different job with the stock ECU than a WB02.

NB trims the AF's under cruise to keep it as close as possible to stoich and this is why when the 02 dies you lose economy.

WB makes a needle move of pretty lights flash
(Or drives a more sophisticated system like an LM1 or a built in WB in a standalone)

 

[jimi87-t]

They're just a gauge/tool and I'm not sure I'd trust one to handle the tune/adjust it anyway as they're not 100% reliable even under ideal conditions.

So what would the "home tuner" use? I don't like dyno's as they don't give real world data. A base line is good to get on the dyno, but IMO it needs tweaked in the real world

 

[jetjock]

The stock sensor is there for one reason: to keep the mixture at stoich during steady state conditions because the cat needs stoich to work. As I've said before, stock O2 sensors exist solely to serve the cat converter. The stock sensor is part of the engine's feedback loop. It makes it run at lowest emissions and the cat cleans up the little bit of mess left behind. Stoich is not the best mixture for performance, it's there for emissions.

A WB is there for monitor only and is typically not connected to the ecu. That doesn't mean it can't be however. If the WB controller has an output (as the LM-1 does) it could be used to replace the stock sensor and be used both for control *and* monitoring. Many people do this but I personally wouldn't.

So it all comes down to a question of using it one way or the other. If you're not going to connect the WB to the ecu then the cheapie A/F meter will monitor your stock sensor and feedback system while the WB will independantly monitor A/F but not provide any control of the engine. I hope that clears things up.

 

[mkiii88supra]

so once past the capacities of the stock o2 like getting bigger injectors, a pump, tuning devices there is no real need for an a/f gauge right?