A/F gauge vs. EGT Gauge

[JITB]

Im having a discussion about this on the protege forums with another member.

He says a/f gauges are useless b/c they are narrowband, and that the o2 sensor doesnt give a accurate enough reading to make any assumptions with. well doesnt the o2 sensor read the oxygen levels for the ECU?

he says that the egt gauges are more accurate, but u need a wideband to read it..

My a/f gauge is as accurate as i thought it would be, car runs rich as hell on full throttle, and lean off the throttle and idle, adn ideal while driving normal. his mind is set on EGT (pyrometers). Anyoen care to add anything to this? Is his information correct?

[flysi00]

a/f are not the best way to go. i would go with EGT

[JITB]

Ive got that part, im just wondering if the a/f gauge is useless as he claims to be...

[green91]

my a/f works great because i have it wired to my wideband. you do NOT need a wideband to read EGTs

[JITB]

well not to read it, he was saying that in order to get the proper numbers to be able to read it correctly you would have to have a wideband to see the correct temps and all that.

Ok, so did u have the A/f installed before u got the wideband? If so are the reading that far off than it was when it was just ont he o2 sensor?

[Jaimecbr900]

He is correct. Most inexpensive A/F gauges are good for a little light show and not much else. They use stock O2's. Those are indeed narrowband sensors. Therefore, their parameters are not good enough for boosted cars.

The EGT in turn uses a probe directly into the exhaust stream. If mounted correctly, it can tell you faster when the engine starts to go lean (higher temps). The only problem here is that some cars run higher temps than others. If you don't know your car really well, you may not be able to know the difference. For example, on my car 1000+ deg temps are normal w/o any boost at all. In other cars that's lean.

The only true A/F gauge that is accurate is a wideband. That is the one that needs a wideband controller to read it. It also requires a different O2 sensor too.

[Danny]

I second what jamie said.

i refer to my AF guage as a dummy light. If i am having probs, i can see if its a major fuel mix issue fairly quickly and decently accurate.

your avg af is useless, just pretty anoying lights. My ears are just as acurate as my dinky af guage. some af guages, wont even read as reach as is needed with some boosted cars.

best route: wideband o2, and EGT guage. Together you can cross refrence them with each other to really see how your cars acting.

usless? imho, no. its a good retard light, tells u quickly if ur O2 sensor is working half way decent, tells u quickly if you have a major fuel problem. ( but then agian, so does a wideband and egt, but thats not the point)

[JITB]

a/f gauge is like stage 1, and egt/wideband is stage 2...i suppose.

[ct9a gsr]

non-wideband a/f gauges are abolsutely useless and just for show... but that's even more reason for everyone to have one in their car... (dude, everytime I push the gas, the light goes all the way to the right, that's so cool!11!!!one!)

[Danny]

^^^ the harsh reality, mine was a little more nice...lol

[JITB]

What if u use it to set your FPR? And it helps fxes aloooot of problems? useless than?

[green91]

you cant. narrowband a/f doesnt read a wide enough spectrum of AFRs to give you any usable info other than minute corrections. a wideband would be fantastic for setting your fuel pressure.

[JITB]

Ok ok...got that part...

Without the wideband...how will ube able to properly read the EGT gauge. If you have to compare readings with the wideband, and the EGT..in order to properly read the EGT? Not everyone uses or needs a wideband..And im not talkin about tuning..im just talkin about for monitoring. IM talkin about without the wideband..you cant compare a narrow band to a waideband.

[aMaZnAzN]

egt all the way man

[green91]

you can use a EGT standalone of a wideband. if your exhaust temps start going up, youre probably starting to lean out... you can use it without a wideband but is more useful with one.

[ck02wrx]

I use both a wide band and an EGT gauge. If I had to choose between a narrow band 02 gauge and an EGT, I'd go with the EGT gauge. I also have a narrow band 02 gauge and it is pretty accurate when compared to readings form the wideband. Would I use it tune with? NO, but by watching the narrow band gauge and knowing were it normally is at 14-1, 13-1, 12-1, 11-1, and 10-1, when compared to the wideband reading, it some what helpful. With that said, the narrow band will not detect sudden changes in AFR and cannot be trusted for tuning and even though the has been surpisingly accurate, I still don't trust it. If you want to know if your idling and crusing at 14.7-1, its a great gauge to have. If you want to monitor the engine under full throttle and can only afford one gauge, get the EGT gague.

[godspeed]

wideband is now so inexpensive these days, you could get them. Try AEM UEGO.

they're fairely simple to install with the plug and play wiring harness with bosch plugs.

They'll give you the a/f ratio in sweeping led and digital layout (for turbo cars that goes under 11).

EGT is great, because you could monitor the temperature of your engine. They give you the right away info on what's going on in your engine. If it goes colder you'll know it's lean, if it's running hotter, you know it's rich... and few other thing, like if your EGT temp goes up, you might have blown an engine... etc.

anyway with both the EGT and A/F you could monitor and tune your car accordingly.

Since you could have the perfect a/f ratio and still have things go bad inside your engine, I think it's good to have EGT to monitor what you're doing is right inside the engine.

my 2 cents

[Jaimecbr900]

EGT is great, because you could monitor the temperature of your engine. They give you the right away info on what's going on in your engine. If it goes colder you'll know it's lean, if it's running hotter, you know it's rich... and few other thing, like if your EGT temp goes up, you might have blown an engine... etc.

You were doing good until this.

It's actually backwards bud. As the EGT temps rise, that shows the engine leaning out. As the EGT temps are lower, that shows an engine being rich. As for EGT temps rising as being indicative of engine condition, that's kinda of assumption rather than monitoring a symptom. In other words, the engine may be blown AFTER the temps climb really high because it was LEAN. But that doesn't necessarily mean that higher EGT temps are indicative of a blown engine. One of the big factors in accuracy of EGTs is the placement of the probe. The optimal location is right into the exh manifold. Sometimes that's not possible, and therefore the further downstream it is the more you have to take that into consideration.

For example, my car is a ULEV vehicle. In order to get there, it requires the car to run leaner than most vehicles, and we're talking about STOCK here. Therefore, my N/A temps are higher than most. My off boost EGT temps are 1200 or more all the time. For most other cars that is very high, for mine it's not. What I look for is for the temps to stay the same WHILE under boost. If I do that, then I'm stoich. If the temps go higher, then I'm leaning and I get out. Follow?

BTW, I will getting the AEM wideband installed in the next few days. This way at a glance I can see the exact A/F w/o having to guess at it.

[BOOSTEDeg]

i Have A Pyrometer And Probe Kit For Sale!!!!!!

[mogallo]

I went with the AEM UEGO wideband and Greddy EGT gauges.... along with the AEM EMS. I dont really think im going to like the lights on the UEGO though.... and the RED led.... BLAH!!! If you have the money, just get both.... wideband and EGT....

COOLNESS x 2

[Mike Lowrey]

This may be a stupid question but given the choice between EGT and Wideband A/F monitoring, why would you not want to go Wideband A/F? Doesn't your EGT get affected by timing as well as your fuel mixture? This could muddy the waters when trying to determine whether you are running rich or lean.

I agree both would be best, but if you had to choose one, why not a Wideband A/F?