Are A/F gauges a crock?

[MisterX]

I've read a lot of posts on Air/Fuel gauges. Some guys praise them and others damn them.

So, what's the story? I've got oil pressure and temperature, boost, and, EGT gauges. I've got one more pod to fill and right now, I'm thinkin' about a clock!

I'm adding sti injectors and a walbro fuel pump. Do I need an A/F gauge?

misterx

[is2scooby]

I have had an Autometer A/F ratio gauge in a supercharged V8 before and I agree that it's just a "light show" (ala KITT in Knight Rider ).

There has been talk that the Greddy A/F gauge is more accurate.

I actually decided not to buy a center gauge pod (which I think is a very elegant solution) because I couldn't think of 3 gauges I'd want to/was willing to run. My list topped out at boost & egt.

I know the only other thing that I wonder about is oil pressure, but I'm thinking the plumbing on that one might be a bit of a bear on the sending unit of that particular gauge.

Good luck with your search for a 3rd gauge! :-)

[MisterX]

Originally posted by is2scooby
I have had an Autometer A/F ratio gauge in a supercharged V8 before and I agree that it's just a "light show" (ala KITT in Knight Rider ).

There has been talk that the Greddy A/F gauge is more accurate.

I actually decided not to buy a center gauge pod (which I think is a very elegant solution) because I couldn't think of 3 gauges I'd want to/was willing to run. My list topped out at boost & egt.

I know the only other thing that I wonder about is oil pressure, but I'm thinking the plumbing on that one might be a bit of a bear on the sending unit of that particular gauge.

Good luck with your search for a 3rd gauge! :-)

Thanks for you input. IMHO, If you want to run run oil temp and pressure gauges, the most elegent solution, from an engineering standpoint, is the Defi sandwich that fits between the block and the oil filter and offers two 1/8 NTP ports to your oil system.

So far, all I've heard about A/F gauges is the "light show" thing. Most people say they are annoying.

misterx

[CoreyRED02]

I have boost, oil pressure, volt, egt, water temp and A/F. I would say that A/F is probably the most useless. That being said it looks pretty sweet front and center on my center gage pod I am putting in an aftermarket stereo so i opted for no clock. I would've gotten a clock instead of the A/F gage if I wasn't planning on the stereo.

C-

[igo380]

does your a/f even look like it is working? The one I have bounces around all the time, essentially doing what it wants. May have to go to a wideband to get any use out of it?

[aussieinstlouis]

It is not the gauge that is accurate or otherwise - it depends on what type of O2 sensor you are using. It is also 'only a light show' if you do not understand what the O2 sensor output is and how to interpret that.

Narrow band O2 sensors do not have a linear output and are no good for tuning, however they are a good 'health check'.

The Greddy gauge does come with a 'semi wide band' sensor and can also be calibrated for a wideband sensor.

I use the autometer gauge hooked into the rear O2 sensor - I also have an EGT gauge and find it useful.

Cheers,

Andrew

[N8DOGG]

actually I just went to get my a/f gauge put in along with my egt gauge. Originally i was planning on hooking the a/f gauge up to the stock rear o2 sensor. however, supposidly in the MY02 wrx the volts of the a/f gauge dont match up with those of the 02 sensor. So basically im buying a new seperate o2 sensor that will give me a more accurate/better reading. If you go this route i think autometer is all gravy

[cyrilgrey]

I was using a digital A/F gauge with a nitrous sytem in my last car. It seemed to be accurate all of the time. At idle and part throttle it was stoich, at full throttle rich, under deccel lean and on nitrous stoich when set up correctly.
When my cat died it reflected a change, and when the air filter needed cleaning it also reflected that change.

[MadDog]

Originally posted by N8DOGG
however, supposidly in the MY02 wrx the volts of the a/f gauge dont match up with those of the 02 sensor.

The Front O2 sensor generates different amounts of current, and uses that to guage A/F. So you can't use the readings off of it, or you'll confuse the readings and won't get a normal guage to read it anyway. The rear O2 is just a normal voltage based one. Unfortunately, it's not usefull for tuning because, well, it's after all 3 of the cats. It's really there as a "cat efficency" tester.