1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

air/fuel ratio gauge

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Old 03-21-02, 08:01 PM
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the torquinator

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air/fuel ratio gauge

An air fuel ratio gauge is supposed to be a very good tool for tuning a carburated engine. I looked into getting one and they are only about $30 to $40. But they work with an oxygen sensor. The advertisement says that if your vehicle isnt equiped with an oxygen sensor you can buy the one that goes with the meter for like $60 to $80! If the meter works with a factory O2 sensor, couldn't you go to the local parts store and pick up an O2 sensor for ~$20, mount it in the exhaust pipe and connect it to that? Would it work? If so you could save like $50.
Old 03-21-02, 08:12 PM
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you can try.i have mine with the cable that goes to the oxigen sensor and the oxigen sensor have only 1 wire
Old 03-21-02, 09:29 PM
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hmmm i was also thinking of hoking up an o2 sensor,
but i wanna know if anyone has some input on a good o2 sensor,
in other words one that can withstand 2,000 + exhaust temps,
im afraid if i shell out cash on a standard o2 sensor it will fail and give incorrect readings.
Old 03-21-02, 11:57 PM
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I got the answer!, its called get a 2nd gen one!. We know that can withstand the heat!.
Old 03-22-02, 12:04 AM
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A standard O2 sensor usually runs more than $20, but they are not very expensive. The A/F meters that read a standard O2 sensor are not really that accurate and leave a lot to be desired. I would think an EGT would be better for us, if you did not want to go with a wideband A/F meter.
Old 03-22-02, 12:20 AM
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Yeah you'd really need a 4 wire wideband to tune a car with.
Old 03-22-02, 01:43 AM
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Originally posted by piston pounder
I got the answer!, its called get a 2nd gen one!. We know that can withstand the heat!.
yeah its also called $280.00 from mazda
Old 03-22-02, 01:44 AM
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Originally posted by Felix Wankel
Yeah you'd really need a 4 wire wideband to tune a car with.
whats a 4 wire wide band?
i have some 4 wire o2 sensors laying around.
Old 03-22-02, 01:46 AM
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never mind im seeing prices around $300.00 for the setup,i'll pass.
Old 03-22-02, 02:10 AM
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Then go EGT.
Old 03-22-02, 12:08 PM
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the torquinator

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about how much does a decent EGT setup cost? And i don't understand why a standard air fuel ratio gauge would not help you tune a car well. I guess I don't really understand how they work other than they sample the amount os O2 in the exhaust and it reads on the meter. Anyone care to give a detailed explanation of how a wideband works and why it is better?
Old 03-22-02, 12:34 PM
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Here a link to a really good thread about a specific wideband sensor, but there is some general info in there to. https://www.rx7club.com/forum/showth...t=diy+wideband
Here's a good description of the differences/advantages:
Here it is in a nutshell:The O2 sensor that is in most cars, like the Mazda,
is only able to read well around the 14.7 Air to Fuel ratio. Those little blinky lights that people add to the car are really only good for very very rough tuning. The RX-7 likes to run at closer to 11:1 mixture under power. The stock O2 sensor is pretty much useless for that range.
No matter what meter or gauge you read the stock o2 sensor with, it's readings are still 'wild'.

The wide band o2 meter some of us are going to make from that kit, is able to read a much wider range, and with a more stable reading that is not as suspectible to temp. variations.
The wide band o2 can therefore be used to tune a car, and better dyno shops have such instruments.
A wide band meter uses a fairly complex set of circuitry to control it, and to read it's value. You can't just screw in a wide band sensor into the stock location, and read it with a simple meter. It's the whole package that is needed. The cool thing about this 'kit' is it is very cheap. They usually cost from $700 to $2000. This kit costs about $300 or so.
The sensor is from a ultra low emissions Honda.

I hope this helps answer some questions!
Quote from lesd
Check out the thread.
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