Subaru OEM Wide band O2 sensor idea

[John at J&S]

Haltech makes the Halmeter with thirty LED's. TWM Fuel Injection in Goleta, CA sells it for about $139.95.

[G3-TEG]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by acracing:
Here's a couple of interesting links I've had bookmarked on the subject.
http://www.diy-efi.org/diy_efi/projects/diy_egor/
http://gadgetseller.com/gauges/ <HR></BLOCKQUOTE>

Awesome.. thanks for those links! Very informative. The first one looks more promising than the second though as it acutally incorporates the use of a wide band O2 sensor.

However, on the front page it says that you must use a 2 cell wide band which is found on a 92-95 Honda Civic 1.5l:

Application/part number:
92-95
Honda Civic
1.5 VTEC
36531-P07-003

Is that correct????? I thought none of those were wide band units?

As for the second link, they sell modified Autometer, etc units that will increase the resolution of the unit, however still uses the OEM O2 sensor. How accurate and precise do you think that is? You are still using a the stock sensor and not a wide band O2.

Also, those units all display the A/F in volts. Does anyone know how to translate voltage into the actual A/F ratio? (ie. 0.90volts = XX.XX : 1 a/f?)

[CivicR]

Hey guys the fabrication of a meter is not the hard part...its just basically just a voltmeter...what makes the wide-band O2 sensors so accurate is the compensation for temp on the unit....the Motec units compensate for the temp of the O2 sensor...if you look at a chart of the specs of the WRX O2 sensor...you would see that as the temp varies so do the readings....so that is why the Motec and similar units are so damn expensive....just do a search for the info Motec and other units...I know I have seen info on how they work....I think it may have seen some info on b16a.com??...if you guys come up with anything please email me..Im interested!

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John
B18C1 Powered 95 Civic EX Coupe
H22A Powered 92 Civic VX Hatch(In the works)
88 CRX HF(Coming soon)

[acracing]

Here's another link.
http://www.geocities.com/CapeCanaveral/3572/oaf.htm

I thought I had some more info on wide band O2 sensors, but I can't find it off hand. As soon as I do, I'll post the links.

[ArturboGSR98]

G3-TEG,
Ok after talking with MarkC he reminded me about something. Analog sweep meters react fater than digital meters. Digital meters is either off or on (1 or zeros). So a digital meter works in steps and takes time to read out what is acutally supposed to be reading.
Why do you think boost gauges or your tach are analog sweep meter and not digital read outs. If you remember honda preludes used to come with a digital tach, but not the new ones. The only Honda today is the S2000 that has a digital read out.

But there has to be a way to combine a anlog sweep meter to the O2 sensor.

art

[acracing]

Here's a couple of interesting links I've had bookmarked on the subject.
http://www.diy-efi.org/diy_efi/projects/diy_egor/
http://gadgetseller.com/gauges/

[G3-TEG]

Hmmmm.. ok i'll take your word for it then..

So anyone know how we can accomplish this?

[zip]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ArturboGSR98:
G3-TEG,
Ok after talking with MarkC he reminded me about something. Analog sweep meters react fater than digital meters. Digital meters is either off or on (1 or zeros). So a digital meter works in steps and takes time to read out what is acutally supposed to be reading.
Why do you think boost gauges or your tach are analog sweep meter and not digital read outs. If you remember honda preludes used to come with a digital tach, but not the new ones. The only Honda today is the S2000 that has a digital read out.

But there has to be a way to combine a anlog sweep meter to the O2 sensor.

art<HR></BLOCKQUOTE>

I think your confusing digital boost gauges w/ digital AF gauges. "Digital AF gauges" are basically voltmeters that react to voltage thresholds instantaneously, via voltage comparators that are evenly spaced. The calculation (not really a calculation but you get the idea) is in meu seconds but that's instant to the naked eye. What you see from common AF gauges are "real-time" voltages since those pesky electrons travel at the speed of light. The quasi-analog Greddy AF gauges differ from the typical AF gauges as explained below.

Digital boost gauges have a microcontroller in a control box that samples the boost pressure a hundred times a second. The microcontroller then calculates the boost reading to determine the amount of sweep needed to send a pulse width to a stepper motor housed inside the gauge. The stepper motor then moves the gauge dial to a corresponding location proportional to the duty cycle sent by the controller. (This is how Greddy AF gauges, Autometer's full sweep fuel pressure gauge,...etc typically work) The calculation by the microcontroller, duty cycle sent, and the stepper reacting, have some delay compared to mechnical boost gauges which has a diaphragm that reacts to boost pressures almost instantaneously.

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Mods



[This message has been edited by zip (edited April 24, 2001).]

[G3-TEG]

Zip to the rescue! Thanks for clearing that up... thats what I was thinking originally, but didn't know how to prove or disprove it.

Ok, so with LEDs its faster and easier to do anyways, so whats the next step?

[12SecGSR]

does anyone know how many wires the WRX sensor has? or the NSX sensor?