Air/Fuel meter or gauge

the head · 08-12-2004, 11:54 AM

Been looking for an a/f gauge. I see that the Auto Meter gauge connects inline to the stock O2 sensor but doesn't really tell you what the ratio is - just lean, stoich, or rich. The K&N standalone setup appears to be the better deal since it has the actual numbers on it. Anyone have experience with either of these?

GETSOMZ28 · 08-12-2004, 01:01 PM

They arent very accurate since they tap into the O2 sensors (which are narrowband sensors). If you want to see your real AF ratio you will need to get a wideband sensor. I have seen them from $350-up

1BadTitan · 08-12-2004, 01:28 PM

I'd like to see an A-pillar pod to hold this gauge for the titan

pciley · 08-12-2004, 09:41 PM

So would I, have looked on multiple vendor's sites, no luck. Wish somebody would make one in time for the blower... need that boost guage and oil temp

Potroast · 08-12-2004, 09:47 PM

Quote:

Originally Posted by pciley

So would I, have looked on multiple vendor's sites, no luck. Wish somebody would make one in time for the blower... need that boost guage and oil temp

I think boost and fuel pressure would be a better choice if you're limiting to two guages.

EGT and a wideband O2 are excellent additions.

And since it's an auto tranny, maybe a trans temp guage just to keep that in check.

pciley · 08-12-2004, 10:03 PM

If you really want to be anal, there are 4-guage pods out for other trucks, prob soon to be for ours too.

I have never had forced induction to know what you would need. Fuel pressure will vary at RPMs, I think I would actually rather have air/fuel ratio guage as that would seem to alert you of an unsafe mixture more quickly that JUST a fuel pressure meter.

I wonder how large the intercooler will be if Stillen puts out a blower. The one they have for the 350Z looks to be over 18" wide and maybe 8" tall. Takes up the whole lower grille. Hope there's room down there for the intercooler and the plumbing.

Sorry to get this thread off track.

"the head" do you have a modification done that would warrant an air/fuel guage? Or are you just preparing for future mods?

the head · 08-13-2004, 06:13 AM

Preparing for future mods, mainly. Also considering nitrous. I can have all the pressure gauges in the world but that won't tell me if I have it jetted lean (very, very bad). Still leaning on the one that wires in to the stocker just so I know it isn't going to go bang. It shouldn't but I'd just like the fuzzy, warm feeling. This wouldn't be to tune the engine for fuel or ignition curves or anything like that so I'm not 100% sold on the wideband setup for the price. Especially since I can buy an entire nitrous kit for that kind of money.

the head · 08-13-2004, 08:02 AM

I went ahead and ordered a gauge from Summit (Summit brand - ie. Cyberdyne) and a ring to tilt it. I'm planning on sticking it where the 4x4 knob goes (I have a cover there - 4x2). Now all I gotta do is figure out which wire to tap and it's all good...

Potroast · 08-13-2004, 10:20 AM

fwiw, a narrowband O2 sensors and A/F guage just looks purdy -- it doesnt do any damn good to let you know anything is wrong. A wideband, however, is accurate enough you can tune with it.

pciley · 08-15-2004, 12:42 PM

Won't it still alert you of rich/lean condition? Just not as accurately as "how much rich or lean?"

the head · 08-19-2004, 07:30 AM

I downloaded the Nissan service manual last night, looking for wires to tap into for the gauge I bought. After looking through it, we may actually have a wideband in there, stock. The heated O2 sensors are there (0-1 volt) but there are two other air/fuel sensors that are upstream of the cats. Voltages for the 4 wires coming out of there are 2.3 volts for two, 2.6 volts for one, 3.3 volts for the other as listed in the troubleshooting section for those sensors, at idle with the engine warm. These all go directly into the ECM. The description of the air/fuel sensor discusses a Nernst concentration cell and this is also mentioned when reading up on the widebands out there. I'm going to do some more digging, but we may be lucky enough to be able to just get a display if the voltages are the same as an aftermarket setup.

GETSOMZ28 · 08-19-2004, 07:41 AM

I doubt the front O2s are wideband. The front ones are what the computer uses to adjust AF ratio (ie if it senses a lean condition at part throttle, it will dump more fuel at WOT to compensate). Keep us informed of your findings. I do feel we could gain a few hp if we had a way to adjust AF ratio, as most stock vehicles come from the factory set a little on the rich side.

Potroast · 08-19-2004, 10:01 AM

where can I find the service manuals?

the head · 08-19-2004, 01:26 PM

Do a search but www.nissan-techinfo.com

After reading the description, this has the same exact components and operating summary that the Bosch sensors used in the widebands are describing. I'm really thinking it is the real deal especially considering it is a 6-wire sensor. One power, one ground (probably for a reference signal) and four others that I haven't gotten a thorough explaination of. I don't know that a gauge from any of the aftermarket widebands would necessarily work but once you figure out the curve I'm sure adding a simple volt meter with handmade marks on it would suffice.

In the meantime I'm going to stick the narrowband gauge I got and see what kind of Xmas lights it throws out.

syntrix · 08-19-2004, 02:47 PM

6 wire does not mean it's a true wideband. Teh autometer gauges are basically idiot lights and won't tell you very much at all.

I'd recommend http://www.innovatemotorsports.com LM-1

I got one that I tested a lot of new features on the rx8. I did some graphs here:
http://rx8.swankmonkey.com/airfuel/