Air/Fuel (AFR) gauges worthless???

[Zmann42087]

I was reading some threads on here earlier today, and one thing in particular caught my eye...

DSMtuners thread

Is it true that (stock) narrowband air/fuel gauges are worthless? Until today, I'd never heard that. If they really are inaccurate, can somebody tell me why the heck so many people have them???

I'm going to be purchasing gauges in the next couple weeks. One of those gauges was going to be an AFR gauge, but now I'm not too sure... I really don't want to spend the money on a wideband air/fuel gauge as I don't really need it for tuning purposes right now. I was planning on purchasing a Faze air/fuel gauge or maybe a lower-end Autometer air/fuel would do the trick, but I guess those might not work now. Can someone please confirm or deny the new info I found?

 

[v2ner]

Wow...wideband for $70. I've been gettin mine for $200 a pop.

 

[DGajre777]

Wow...wideband for $70. I've been gettin mine for $200 a pop.

The probe is $70. The cheapest wideband controller with probe is $200 (LC1).

 

[jepherz]

I don't know why someone above would say AFR gauges are innacurate.....

The reason an AFR gauge has little to no place with a narrowband is cause all it will do is bounce around stoich when in closed loop. No narrowband o2 sensor is calibrated beyond the the 14.7 point, meaning at a certain voltage, they all read about stoich (14.7 AFR, 1.0 lambda) but you can't tell what any other voltage corresponds to.

The worst I have ever seen was some dude with an AFR gauge on the passenger side of his car....

 

[boostedinaz]

Personally, If you wnat to know what your A/F ratios are looking like i would go with an EGT gauge. An egt will let you see if your running lean even at cruising speeds. Unlike an A/F gauge which only works when your in the throttle.

I will have to disagree with this. I can make my car fairly rich and because of this some of the flame or even just heat from that rich condition can escape into the manifold. This will cause EGT's to go up because the temp is higher even though I am running rich and not lean. Using an EGT gauge for tunning is the same as using a narrowband for tunning. A guess at best.

Everybody just go stand-alone so you don't need any gauges except for boost(if you're using a MBC).

Not many of us want to drive arouind with an open laptop in our car and have to glance away from the road to see what is going on. Gauges are an important part of owning a modified vehicle.

I don't know why someone above would say AFR gauges are innacurate.....

The reason an AFR gauge has little to no place with a narrowband is cause all it will do is bounce around stoich when in closed loop. No narrowband o2 sensor is calibrated beyond the the 14.7 point, meaning at a certain voltage, they all read about stoich (14.7 AFR, 1.0 lambda) but you can't tell what any other voltage corresponds to.

The worst I have ever seen was some dude with an AFR gauge on the passenger side of his car....

Great answer.

A narrowband is NOT good for tunning at all. Sorry to break it you guys but it just isn't. Back in the day(when that AFC article was written) the only way to get a good accurate tune was to head to the dyno and have a wideband sniff while you make pulls. If you didn't have access to that then what they said would have to work well enough because well that is all that was available. The problem lies in what was posted above. The narrowband is not accurate except for the stoich area of 14.7. So if you are running around at 12:1 the nifty light may very well be bright green. You keep cruising and beating on the car all the while slowly hurting it.

In the technology filled world we live in now you can pick up a real wideband O2 and tune on the freeway all day. While this will still not a be a true dyno tune to make the most power it will get you a lot closer than anything else out there until you do get to the dyno.

Bottom line is a narrowdand is used for keeping the car running normal on cruising conditions. At WOT it is ignorad by the ECU all together so spend a few hundered and by a real wideband. For some reason a lot of people don't have the money to do it right in the first place but they always have money to do it over again. Weird.

 

[wallyman]

I will have to disagree with this. I can make my car fairly rich and because of this some of the flame or even just heat from that rich condition can escape into the manifold. This will cause EGT's to go up because the temp is higher even though I am running rich and not lean. Using an EGT gauge for tunning is the same as using a narrowband for tunning. A guess at best.

Its not very likely a rich condition i sgoing to make your egts sky rocket. The only time you will see this is when you let off the throttle and have some built up fuel left in your manifold. Besides an EGT gauge would never read this quick jump in temperature.

I agree that you cant use an EGT do a complete tune, but it would be more accurate then an A/F gage. Its not a complete shot in the dark if you have some experiance.

 

[v2ner]

That's right, it's not a shot in the dark. If you're experienced, it should be fine using the EGT only but to fine tune, you should use at least wideband. You definitely don't NEED an A/F ratio gauge as it is a waste is space...IMO. As for the laptop.... ..only the fast and the furios drive around with it hooked up. I don't know about you but I only hook it up to tune or solve an issue.

 

[boostedinaz]

Its not very likely a rich condition i sgoing to make your egts sky rocket. The only time you will see this is when you let off the throttle and have some built up fuel left in your manifold. Besides an EGT gauge would never read this quick jump in temperature.

I agree that you cant use an EGT do a complete tune, but it would be more accurate then an A/F gage. Its not a complete shot in the dark if you have some experiance.

You can easily make the EGT go up by running rich. i can change my setting in DSMLink and watch it clime quite a bit and it will not be knocking. It does and has happen especially since any one trying to tune with it would have to be a bit of a newbie.

That's right, it's not a shot in the dark. If you're experienced, it should be fine using the EGT only but to fine tune, you should use at least wideband. You definitely don't NEED an A/F ratio gauge as it is a waste is space...IMO. As for the laptop.... ..only the fast and the furios drive around with it hooked up. I don't know about you but I only hook it up to tune or solve an issue.

It is a shot in the dark. Even with a a fast reacting probe it is still way to slow to give any sort of usuable information. The reason I said in my above comment that only a newbie would tune with it is because any knowledgable person would not use an EGT or an narrow band O2 gauge to tune and any shop that does tunning for a living would laugh as well. They are in accurate, slow to react, and not designed for tunning at all. They are MONITORS and nothing more. If you want an equally silly comparison try to use your oil pressure gauge as a tach. After all oil pressure goes up with RPM so if your gauge gets to a certain point you need to shift. That is the same thing going on with these two devices. Again they are just a monitor to see what is going on with the engine, not a tunning device by any means.

 

[Slippi84]

While I have one and don't use it for tuning as I have posted on here that they are useless before I have to somewhat play devils advocate. What if you tune your car with proper tools say dsmlink and your light does the same thing all the time, but then something like a injector oring or something fuel related starts leakin or your pump starts to go and your not flowing lie you were before and your light show starts acting diffrent then it usualy does even if it doesn't tell you what it tells you to buts out the logger and check everything. I think that is worth having one. I think if that's it's purpose that it's less rice than venting your bov. Just my .02

 

[wallyman]

You can easily make the EGT go up by running rich. i can change my setting in DSMLink and watch it clime quite a bit and it will not be knocking. It does and has happen especially since any one trying to tune with it would have to be a bit of a newbie.




It is a shot in the dark. Even with a a fast reacting probe it is still way to slow to give any sort of usuable information. The reason I said in my above comment that only a newbie would tune with it is because any knowledgable person would not use an EGT or an narrow band O2 gauge to tune and any shop that does tunning for a living would laugh as well. They are in accurate, slow to react, and not designed for tunning at all. They are MONITORS and nothing more. If you want an equally silly comparison try to use your oil pressure gauge as a tach. After all oil pressure goes up with RPM so if your gauge gets to a certain point you need to shift. That is the same thing going on with these two devices. Again they are just a monitor to see what is going on with the engine, not a tunning device by any means.

Yes but your missing the point. I know a wideband is the proper way to tune a car. My statement is saying that if you were going to fill that gauge pod your better off putting in an egt then an a/f gauge. Im not using the EGT to tune im using it to monitor a/f ratios. Assuming your fuel maps are somewhere in the ball park an EGT will give you more stable numbers then a flashing a/f gauge. Your scenario of too much fuel causing egts to climb is worst case. Yes you could drive around using a wideband 02 sensor to know exactly what your a/f ratios are but this a somewhat cheaper alternative.

 

[boostedinaz]

Yes but your missing the point. I know a wideband is the proper way to tune a car. My statement is saying that if you were going to fill that gauge pod your better off putting in an egt then an a/f gauge. Im not using the EGT to tune im using it to monitor a/f ratios. Assuming your fuel maps are somewhere in the ball park an EGT will give you more stable numbers then a flashing a/f gauge. Your scenario of too much fuel causing egts to climb is worst case. Yes you could drive around using a wideband 02 sensor to know exactly what your a/f ratios are but this a somewhat cheaper alternative.

I'm not missing the point at all.

An EGT gauge no matter how you spin it is not an accurate way at all to tell A/F ratio. Being on step better that the worst is still not a good thing to promote. There are so many variables in EGT temps that it would be impossible to say, "ok at X temp I am about 11.0 at WOT." There is no way to coralate any sort of temp to any sort of A/F ratio.

Will an EGT gauge tell you if you are getting to hot, yes it will. Will it let you know you are possibly hurting things, it could. Can it tell you your A/F ratio at any given time nope.

 

[DGajre777]

Don't argue with a wiseman dude. They are always (well 99.99%) right.

 

[wallyman]

I'm not missing the point at all.

An EGT gauge no matter how you spin it is not an accurate way at all to tell A/F ratio. Being on step better that the worst is still not a good thing to promote. There are so many variables in EGT temps that it would be impossible to say, "ok at X temp I am about 11.0 at WOT." There is no way to coralate any sort of temp to any sort of A/F ratio.

Will an EGT gauge tell you if you are getting to hot, yes it will. Will it let you know you are possibly hurting things, it could. Can it tell you your A/F ratio at any given time nope.

WOW that has to be ignorant statement i have ever heard. What do you think they used before wideband 02 sensors? Besides whats the number one reason for running hot? My guess would be because your running lean. If you cant correlate the relations ship of being lean=hot egt, then you dont need to be tuning a car.

 

[DGajre777]

WOW that has to be ignorant statement i have ever heard. What do you think they used before wideband 02 sensors? Besides whats the number one reason for running hot? My guess would be because your running lean. If you cant correlate the relations ship of being lean=hot egt, then you dont need to be tuning a car.

There's a thread on here I read that one person melted their pistons at 1600F and another person ran fine at 1700F. This is the problem. Just because you hit a certain EGT doesn't mean you melted something. You can't correlate EGT temp with your air/fuel ratio. We all agree with you that Lean = Hot EGT, BUT how hot of an EGT = Lean, is the question. Tuning with an EGT is best guess, it is a warning gauge, not a tuning guage. If you want a tuning gauge, get a wideband o2.

 

[mitsugst97]

Fun to watch you guys fight for the same point..

Gauges are ment to work in conjunction with each other. (esspecially the less accurate ones, i.e EGT and A/F) That's why your DSMLink monitors many things not just one....

Every gauge has it's purpose yes even the A/f! now i am not saying that you can do a good tune off one, but it can tell you a few basic and general things. same with EGT.. different situations can cause similar responses.

I have driven several cars with A/F gauges "Light shows", and it isn't that distracting.. unless you guys have some Hella bright ones... But i would never say that my Tune is good because my narrowband A/F gauges says so,, that would be dumb!


to the original poster.. if you want it as an on-the-fly monitoring system get a triple gauge pod and load it with BOOST+A/F+EGT... then you get a cool light show and 2 gauges that will work together to help show you whats going on.....

lets not

 

[boostedinaz]

WOW that has to be ignorant statement i have ever heard. What do you think they used before wideband 02 sensors? Besides whats the number one reason for running hot? My guess would be because your running lean. If you cant correlate the relations ship of being lean=hot egt, then you dont need to be tuning a car.

First off clam down, second off my statment was far from ignorant.

So then since you seem to think I am ignorant to this then by all means educate us all. Please tell us at what temp we would be running to lean. Also please specify as to, give or take, what YOU think that temp would coralate to as far as A/F ratio goes.

Now keep in mind while finding out all these great things, that EGT placement, probe type, wire type, outside temp, and how long the car has been running, the accuracy of the gauge, the rnage of the gauge, as well as health of the engine can change all of this. On top of all of that I have seen at least a 150 degree difference in EGT temp from one car to the next even when the probe is in the same location on the car. What car was running lean and what car was running well? You tell us since you seem to have an excellent grasp on this type of tunning and monitoring.

As far as what people used to do I already covered that in a previous post. We now have much better equipment so why would some half ass guess something when they can have an extremely accurate reading of exactly what they want to know?

 

[wallyman]

I didn't call you ignorant i said you made an igonorant statement. Second off yes you are correct. of course your not going to be able to get an exact a/f ratio from a temperature. But when i see im at 1600-1700 degrees at a certain RPM and load i know im running lean. But again im not talking about tuning with an EGT i said monitor a/f ratios. There is a difference. The whole point was you can monitor a/f ratios say if your crusing down the highway where an a/f gague won't work.

This topic has been like beating a dead horse. Your not going to agree with my point so im just going to drop it.

 

[wallyman]

Sorry for the poor punctuation on the last post. I re-read it and I had a couple (meaning a lot) of run on sentences.

 

[boostedinaz]

I didn't call you ignorant i said you made an igonorant statement. Second off yes you are correct. of course your not going to be able to get an exact a/f ratio from a temperature. But when i see im at 1600-1700 degrees at a certain RPM and load i know im running lean. But again im not talking about tuning with an EGT i said monitor a/f ratios. There is a difference. The whole point was you can monitor a/f ratios say if your crusing down the highway where an a/f gague won't work.
This topic has been like beating a dead horse. Your not going to agree with my point so im just going to drop it.

We are making the same point, but you are assuming that everything that the EGT gauge tells you has to do with the A/F ratio, and it being lean at higher temps, and that is just not true all the time. There are other instansec when the EGT gauge may read hot that don't indiacte a lean condition.

An A/F gauge, even the lame ones, will read lean far faster than an EGT can react if the car went lean. Saying it won't do that on the highway like an EGT gauge is wrong as well. Everytime I let off the gas in my car or went slightly lean, sadly it did have an lame A/F gauge at one point, it would react very quickly and the EGT gauge would slowly react. On top of this most gauges are not very accurate at there extreme begining or end of motion. On my 1600 degree EGT gauge I know that while the gauge points to 1600 it may be higher or lower and by how much I don't know. This is the one reason I may switch it out to Autometers new gauge that goes up to 2K.

I will as well drop it as I think I have made all my points.

 

[leet]

Thank God.

 

[Attack Eagle]

You have a battery light that will come on if the alternator output drops below acceptable levels, you don't need a volt meter. Most higher quality caps have built in volt meters, you don't need one in cabin to try to look fast or impress people.

. Yes, narrow bands are useless for WOT tuning and anyone that's using them for that is a retard. But they have their place for cruise/part throttle tuning and engine monitoring. You need to know how to read it and notice patterns, or how to tell normal O2 behavior from non-normal O2 behavior. Having a rich/lean indicator for $50 can be better for most peope than having a $500 wideband. Especially when most dynos have built in wideband loggers. You're an idiot if your tuning only on the street anyway.

hmm. I'll address your last comment first. Most places in this beloved country do not have an AWD dyno. Some do not have an AWD dyno within 6-8 hours drive. You have to tune on the street in those cases. at least to get it close enough to not waste your time or have to trailer the car 2 days for dyno tuning.

A narrowband is useful for telling you that the ecu is hunting up and down for stoich. That is all. As someone said though, that info is already available on a logger. Also You have a light on your dash that tells you your o2 has failed. And it DOES work well. It's called a MIL or CEL. Otherwise you are simply seeing " not stoich rich, not stoich lean, stoich" (translation, I'm hunting around stoich for fuel economy right now). or not stoich lean, not stoich lean, not stoich lean< (translation you are not at 14.7 you are at 14.9 or higher) or not stoich rich,not stoich rich,not stoich rich (translation you are between 14.5:1 and 9:1). Very helpful for tuning. Besides the ecu tunes those parameters on it's own anyway... that is what closed loop operation IS. Why do you want to fight the ecu to try and manually tune it? The ecu will just adjust it's trims to undo your work.


the light on the dash for the alternator on the other hand DOES NOT work so well. I only got the light when the belt came off... not when the alt. failed and was putting out practically no charge. Of the alternator problems i have had, only the belt snapping ever triggered the light. Both a bad connection at the battery causing a no charge situation and a fail-ING alternator did not.

Finally anyone who would suggest running to the trunk to read the voltage while driving down the road is an idiot. Anyone who thinks having a decent amp requires a cap is an idiot. Don't be that guy. thought luckily if you have a Turbo Timer it probably has a Volt setting on it.

 

[DGajre777]

Finally anyone who would suggest running to the trunk to read the voltage while driving down the road is an idiot. Anyone who thinks having a decent amp requires a cap is an idiot. Don't be that guy.

That was funny.