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-   -   Question about AEM "simulated narrowband" ouput (https://www.miataturbo.net/diy-turbo-discussion-14/question-about-aem-simulated-narrowband-ouput-33880/)

rippledabs 04-11-2009 11:51 AM

Question about AEM "simulated narrowband" ouput
 
I got an older aem wideband controller that doesn't come with a gauge.

AEM - Wideband UEGO Controller Modules

To add on a gauge, it would cost $200, which is the same price as the newer aem/gauge/controller unit.

However, the controller that I have outputs a "simulated narrowband" 0-1V output that they claim can be inputted into a stock ecu. I attached a table of the output of the simulated narrowband. My question is, can this output drive a basic narrowband gauge?

I just want a gauge as an "oh shit" meter. You guys think this is an OK idea? I have a link ecu, with a display pad, where I can get exact AFR when needed. It's just a little cumbersome to get to.

Volts Lambda AFR
0.48 1.41 20.64
0.49 1.29 18.89
0.51 1.19 17.42
0.52 1.13 16.54
0.54 1.08 15.81
0.55 1.03 15.08
0.57 1.00 14.64
0.58 0.98 14.35
0.59 0.96 14.05
0.61 0.94 13.76
0.62 0.92 13.47
0.64 0.90 13.18
0.65 0.88 12.88
0.67 0.87 12.74
0.68 0.85 12.44
0.70 0.84 12.30
0.71 0.82 12.00
0.72 0.81 11.86
0.74 0.79 11.57
0.75 0.77 11.27
0.77 0.76 11.13
0.78 0.74 10.83
0.80 0.73 10.69
0.81 0.71 10.39
0.83 0.70 10.25
0.84 0.68 9.96
0.86 0.67 9.81
0.87 0.66 9.66
0.88 0.64 9.37
0.90 0.62 9.08
0.91 0.61 8.93
0.93 0.59 8.64
0.94 0.58 8.49

y8s 04-11-2009 11:58 AM

that doesn't look like a standard narrowband output. it should jump from .3ish volts to .6ish volts on either side of 14.7 roughly.

kinda like this:

http://wbo2.com/2a0/afrnbb.gif

the numbers you posted look somewhat more linearized.

but!

they should work fine with a gauge.

TurboTim 04-12-2009 12:22 PM

I have the same WBO2 box, purchased it before the gauge type came out. At the time I also had one of those cheap narrow band led gauges and I tried the narrow band output. For some reason the gauge was "blurry". Like multiple leds would be light at one time, and the brightness of the leds was poor. It makes no sense to me, those gauges are just volt meters basically. Anyways, the gauge worked fine tapped onto a narrowband O2 sensor, but not so fine on the wbo2 narrowband output.

If you have a gauge, rig it up quick and try it. Maybe I had a ground problem somewhere.

TurboRoach 04-12-2009 06:14 PM

It looks like the AEM simulated output only has half the voltage range of a regular O2 sensor. Maybe a ckt that offset the voltage by -0.5V and scaled by 2 would give a better range over the LEDs.

rippledabs 04-12-2009 11:11 PM


Originally Posted by TurboRoach (Post 394923)
It looks like the AEM simulated output only has half the voltage range of a regular O2 sensor. Maybe a ckt that offset the voltage by -0.5V and scaled by 2 would give a better range over the LEDs.

yeah, i have been researching a little more the last couple days, and a narrow band gauge is just a voltmeter with 0-1 v range. So if i got that 20 LED autometer gauge, it's kinda weak.

From stoich to full lean, it only span 1 led light. And even at 10 AFR, it will still display that it's in the stoich zone.

I have been trying to figure out how to play with the voltages like that. Can you point me to a place where I can learn more about offsetting and scaling voltages?

y8s 04-13-2009 09:54 AM

You could get a gauge designed for a wideband with a 0-1V input... or find someone to make you a circuit that amplifies the signal 5x.

TurboRoach 04-13-2009 01:56 PM

I've already got the same setup, AEM w/o Gauge & Autometer NBO2 gauge. When I get time later this week I'll work on the circuit.

I don't know of any websites that would be terribly useful, but you could try searching for op-amp ckts. I was thinking a summing type with some gain would work.

rippledabs 04-13-2009 05:27 PM

1 Attachment(s)
With my complete lack of electrical knowledge, will this work? It's a voltage divider circuit with a magical voltage doubler, but do voltage doubler exist?

I searched google for one, but the electrical jargon scared me off.


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