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Discussion Starter · #1 ·
OK, I'll admit it - I now nothing about oxygen sensors. I have tried to own nothing but pre-smog cars, and have been pretty successful. But, now I want to mount an oxygen sensor on my '65 Sprint GT to run one of those little fuel ratio meters, so I need to step out of the dark ages.

My basic question is: Do all oxygen sensors mount using the same diameter threads? I had my local muffler shop weld a sensor bung into my downpipe - what they installed has female threads measuring .645" id, or 16.4mm. So, I am assuming that something with a 17mm male thread will screw into this. Is 17mm a universal thread for oxygen sensors? Or, if there is no such thing as a universal sensor, is 17mm correct for a sensor that would fit a later model Alfa Romeo?

Question #2: I surfed the website autopartwarehouse com ("LOWEST prices Guaranteed!!!!!"), and found that they carry 4 or 5 oxygen sensors that fit 164's and late spiders. The price varies from $124 down to $30. Naturally, I like the $30 one best (heck, I only paid $15 for the fuel ratio meter *). autopartwarehouse com seems to determine price based on 1) Bosch versus generic, 2) multi-wire versus one-wire, and 3) with connector vs unterminated. Naturally, the one for 30 bucks has no brand name, one wire, and no terminal. But, I'm OK with that - I think I can crimp on a terminal for less than $94. Yea, I know that multiwire sensors contain a pre-heater to ensure that they read accurately immediately after starting a cold car (OK, so I do know a little about oxygen sensors). But, given that I don't need that feature, and given that my fuel ratio meter works with a 1-wire sensor, am I missing something in gravitating toward the el-cheapo sensor?

< * My $15 fuel ratio sensor comes from JayCar Electronics, located in Silverwater, NSW, Australia (Jaycar Electronics, product # KC5195). And, it's delivered as a kit with no case. But, hey, for $14.95 (that's Australian dollars, mate), how wrong can I go? >
 

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Well, if it is only for the A/F meter you do not need anything specific or fancy... Just make sure that it works on the correct voltage range that the sensor has: either 0-1 volts, or 1-5 volts. The O2 sensors that are OEM actually connect to the ECU and the ECU uses the sensor signal to make fuel delivery adjustments (enrich or lean out the mixture). To get more accurate readings the sensors used in later cars are actually heated when the car is started (hence the use of more than one wire), so that there is no need to get to full operating temperature, but I don't think you have to worry about that...

Best regards,
 

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G'Day Jay,

Thread is 18mm x 1.5mm I believe.

Check out eBay motors, search for oxygen sensor, down the bottom of the list click on 'See additional Buy It Now items' then sort the new list by lowest price and you will find some under $10. Photo's show used but ad states new, you may have to ask for confirmation.

I have the same Jaycar display, has been working for over 5 years so far.
 

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I'd suggest a 3 wire setup myself as the heating element ensure that the sensor stays warm enough to work pretty much all the time as opposed to the much more 'spotty' single wire types.

Query:

Is this upgrade to an O2 sensor for the purpose of actually tuning to as accurate a level as possible, or just to get an A/F gauge in there to see if it's sorta close + the novelty?


I ask because if it's for actual factual tuning, you should consider a wideband sensor (1 to 5 V operating range) w/gauge over the narrowband (.1 to .9 V operating range) stuff you've been looking at.

Now, right off the bat, the wideband with a gauge is GREATLY more expensive than the same combination in narrowband.

However, the trade-off is that the wide is significantly more accurate with rich mixtures than the narrow.

It also has the really sexy advantage of being able to produce *actual mixture numbers and yet still retain the cyclic LED's around the perifery that the narrowband gauges have.

*EG: if you're right at the moment at a 12.5:1 ratio, that's exactly what gauge will show in it's readout. The narrowband, if you could even find a gauge with a numerical readout, would be showing anything from .750 to .850 V for the same ratio, and even that is subject to fluctuation based on the immediate temperature of the sensor proper.


Still in all, you can get a pretty fair idea of what's going on with the narrowband, so it's not like it's a waste to go that route.

The big trick is reading the gauge manual very closely to see how and where it breaks down the ranges a given section of LED's come on, and gearing your tuning efforts to get that specific range of LED's lit.

You'll likely want to go for around 14.7:1 (roughly .5V) when cruising if you're looking for optimum clean emissions and fuel economy and around 12.5:1 (about .775V) when up on it.


There's a thread up in the spider subsection with a pile of different O2 sensors listed in it including prices.

And do note that you aren't actually tied into a sensor specifically labeled as for use in an Alfa. A narrowband O2 sensor is a narrowband O2 sensor and will operate within the same parameters as other narrowband O2 sensors, regardless of what car it was originally 'designated' for. The same goes for wideband stuff.

The primary differences that make for 'model specific' are number of wires (you can go from a single wire type to a multi wire type and get better results, but you can't go from a multi wire to a single wire without issues) shape/size of the outer casing, the amount the element protrudes into the exhaust pipe/stream, and in very rare instances a difference in the bung threading (like where a manufacturer really wants you to buy the very specific, and usually horrifically expensive, part from them that'll only fit that one type of vehicle. Toyota/Lexus would be a good example of one company that does that)

Basically if the **** thing fits the bung and you get it wired in, it'll work.
 

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Hi Jay,

I'm using a Bosch one wire sensor. #12014, and it cost around $20.00. Regarding the wide band sensor, the really hot ticket is a LM-1, which is a wide band and data logger. With this, you can make a run then download to a laptop. Wes Ingram wanted me to try a LM-1, but my pockets were not deep enough. I use a Split Second narrow band A/F meter, which is essentially like the Dynagraph Wes used to sell. This works well for the full throttle setting I'm interested in.

I'd suggest a 3 wire setup myself as the heating element ensure that the sensor stays warm enough to work pretty much all the time as opposed to the much more 'spotty' single wire types.

Query:

Is this upgrade to an O2 sensor for the purpose of actually tuning to as accurate a level as possible, or just to get an A/F gauge in there to see if it's sorta close + the novelty?


I ask because if it's for actual factual tuning, you should consider a wideband sensor (1 to 5 V operating range) w/gauge over the narrowband (.1 to .9 V operating range) stuff you've been looking at.

Now, right off the bat, the wideband with a gauge is GREATLY more expensive than the same combination in narrowband.

However, the trade-off is that the wide is significantly more accurate with rich mixtures than the narrow.

It also has the really sexy advantage of being able to produce *actual mixture numbers and yet still retain the cyclic LED's around the perifery that the narrowband gauges have.

*EG: if you're right at the moment at a 12.5:1 ratio, that's exactly what gauge will show in it's readout. The narrowband, if you could even find a gauge with a numerical readout, would be showing anything from .750 to .850 V for the same ratio, and even that is subject to fluctuation based on the immediate temperature of the sensor proper.


Still in all, you can get a pretty fair idea of what's going on with the narrowband, so it's not like it's a waste to go that route.

The big trick is reading the gauge manual very closely to see how and where it breaks down the ranges a given section of LED's come on, and gearing your tuning efforts to get that specific range of LED's lit.

You'll likely want to go for around 14.7:1 (roughly .5V) when cruising if you're looking for optimum clean emissions and fuel economy and around 12.5:1 (about .775V) when up on it.


There's a thread up in the spider subsection with a pile of different O2 sensors listed in it including prices.

And do note that you aren't actually tied into a sensor specifically labeled as for use in an Alfa. A narrowband O2 sensor is a narrowband O2 sensor and will operate within the same parameters as other narrowband O2 sensors, regardless of what car it was originally 'designated' for. The same goes for wideband stuff.

The primary differences that make for 'model specific' are number of wires (you can go from a single wire type to a multi wire type and get better results, but you can't go from a multi wire to a single wire without issues) shape/size of the outer casing, the amount the element protrudes into the exhaust pipe/stream, and in very rare instances a difference in the bung threading (like where a manufacturer really wants you to buy the very specific, and usually horrifically expensive, part from them that'll only fit that one type of vehicle. Toyota/Lexus would be a good example of one company that does that)

Basically if the **** thing fits the bung and you get it wired in, it'll work.
 

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You can try this crowd
DIYAutoTune.com Megasquirt Kits / Assembled Engine Management Systems, Wideband o2 Sensor Systems and tuning products
Or since you've signed up to the buy Aussie campaign :)
Tech Edge - Tech Edge, Home
I use their 2J1.

Yep, 18mm threaded bung and you can buy them from various sources, but I made my own.
I have one of the old tech edge kits- and it used a sensor that I had sort of kinda laying around. :D

If you can afford a system with some type of data aquisition, it's a lot better- much safer than trying to read a meter and drive at the same time.

On my race car- it will have an MS set up purely as a data acq system, plus the tech edge a/f meter. Should be a nice, compact set up that uses a cheap PDA to record the data.

(as a very technical note- not all O2 sensors are the same- there are 3 basic manufacturers- NTK, Bosch, and Denso- although the Denso bits made it on very, very few cars. Between the NTK and Bosch, thers is a very slight voltage shift at the lambda = 1 point- noticable if you are trying to make some kind of emissions standards, but not for the usage on this board... for the WB sensors, the circuitry for the Bosch vs. NTK sensors is very different, so they do not mix at all)

Eric
 

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Discussion Starter · #8 ·
Well, Here's what I ended up doing:

A little research on the web indicated that NTK one-wire narrowband sensors were available for around $14 (of course, shipping & handling adds another $10). Oddly, NTK seems to be made by NGK, the sparkplug people. Dunno why the swap in letters. Anyhow, I phoned NGK tech support, and they were very helpful - basicly, they confirmed that the cheapo NTK sensor does have a 18mm X 1.5 thread.

I bought a NTK 21002 from "sparkplugs.com" (the box said Monarch Products, Inc) in Menifee, Calif, for $14.85 (plus yada yada). It arrived the next day, and fit just fine.

A follow-on question: the NTK had an odd connector - it almost looks like an old-fashioned auto radio antenna connector. Can I just chop that thing off, and crimp on a spade lug? Or, is there something magical about the connector? And, if "yes", then where would I get a mating connector? (I know, from a junkyard).

Thanks to all who replied. I understand that wideband sensors are superior to narrowband, and that 3 wire is better than 1 wire. But, my little fuel ratio gauge accepts narrowband input, and I can live with waiting for the sensor to warm up before getting accurate readings - it isn't as if it is controlling anything except the gauge.
 

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As it's a single wire, yes, you can lop off the connector without any worry about creating something silly like a short.

Spade lug, bayonet/bullet connector, solder and shrink wrap, they're all good, though the solder and wrap would be the one that would assure the best contact and longevity.

If you use either of the other methods, obviously you'll want to insulate the connection to the best of your ability.

Just depends on whether you want to 'permanantly' wire it to the gauge or not.
 
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