JoshP

Who here runs an A/F meter on their rex?
i'm thinking of getting one as my car has been kinda finicky lately.
pros/cons???
Josh

JIMMY54

iTrader: (2)

I got one, It was soooo easy to install. And it looks wicked at night. It just gives you an idea of your mixture and when the car backfires the guage goes into the Rich Zone!! It's interesting to watch.

peejay

Yeah, they rock. I have the Radio Shack digital universal meter (AKA a DVOM... sleazy me) which has far far better resolution than having 10 little LEDs. O2 sensors are very biased towards the middle... at something like .3v to .7v is a very narrow range of air/fuel ratios... like about half a point in each direction! That means 4 of the lights on a typical 10-LED unit are meaningless - you're very close to stoich. Super. We don't want to run stoich! We want to run lean when cruising (Oh yes you do! N/As tolerate very lean mixtures very well, gotta take advantage of the high turbulence!) and we want to run rich at full throttle. How rich is 8 lights? How rich is 9 lights? Towards the ends of the scale it becomes a lot more compressed - there is a fairly large difference between .925v and .975v, even though both would show the same reading on a 10-LED "gauge".

They're lots of fun too. Like if you have an ignition-based rev limiter, the readout goes psycho when you hit the limiter... when you're rich there is very little oxygen in the exhaust compared to in the atmosphere, and this differential generates a voltage in the sensor - so you have your .9v or whatever. When you hit the limiter, unburned fuel AND OXYGEN are in the exhaust, so it sees all that free O2 and sends a lean signal, but it's only POCKETS of O2 so the readout goes berserk.

(Garth Algar moment) This was supposed to a lot shorter...

AJC13B

I have a Haltuner A/F meter installed in my dash.....

speckamp

I've got the summit racing one.

it's intresting to watch the how the ECU decides to go from closed loop to fuel map. Closed loop I might see it bounce around between 1 bar lean and stoich, but once I hit the fuel maps I'm usually 2 bars rich. It's good to know that everything's working like it should...

and for 35$ is looks pretty

JoshP

any pics of the install? what exactly do i need? an o2 sensor and what?
thanks guys
josh

speckamp

It's real easy, 3 wires.. +12V, ground, signal from the 02 sensor.

the 02 sensor should go pretty close to the motor, if you've the stock manifold on there I'm not sure how yer gonna get a bung welded in there. Some 12A's I believe have them for the emissions bs...

--matt

BadAssRX-7

Josh, i got the OLD cyberdine A/F that summit sold now its a diffrent company but looks the same. you need a o2, guage, and some wire, also if you want to put it on the A piller a pod, i have a 1 and a 2 a piller on my 83 l.e. theres some pics.
http://www.imagestation.com/album/?id=4292366459