being the cheapo that I am, what would it take to build a A/F ratio tool out of an O2 sensor I could put in the tail pipe and connect it to some sort of gauge

Has an anybody done this? Suggestions are welcome....

O2 sensor puts out millivolts, i think, so you could put a galvanometer on it and then calibrate it.

from what I understood, such a device is useless unless you use a wideband O2 sensor ($$$$$$)

I think you are right, I've seen some topics talking about wideband sensors.


If I can't build one...where can I buy one and how much?

A narrow band O2 sensor will put out 0-1volt. The problem with a narrow band sensor is it is acts like a switch (see graph below) If you really want to tune with the sensor you will need to get a wideband O2 sensor. There are many compnies out there that make the required interface modules. These run between $150 and $300. Try searching "wideband O2". I built a 2Eo kit from TechEdge. This is a Australian company. With the slide in the exchange rate though there are other cheeper alternatives out there.

On wideband: Innovate makes the LM-1, which is $350, and includes a display and data logging. They also make the LC-1, which is $200 (including a sensor and a weld-in bung), but doesn't have a display. You can program the LC-1 to display on a voltmeter, including an LED voltmeter you can build yourself for $10 or so.

For about $45, you can buy a narrowband sensor and make the same LED voltmeter mentioned above. At stated, the narrowband isn't really useful unless you're only trying to tune to 14.7:1, which you will not want to do on Type IV.

My $0.02

The LM1 seems to be the cheapest route. $350 is not lunch money but if you think about spending a couple hours worth of shop time @ the going rate for a tech to dyno and/or dial in your air/fuel mixture the shop time will likely run about $150 to $200. If you own the device you can do it over and over and over on other engines, friends engines (who'll likely not pay you with $ but will be greatful...), and you'll know that you can do another thing on your car.

I'm on the cusp of doing this myself - maybe we'll learn together.

-pt

thanks pete....i also found a couple online for a bit cheaper

check out this one...

linky

Kewl!!! Keep me posted if you scoop one up. I'll do the same w/you.

-pt

Drew, read carefully. The Zt thing is not cheaper, but quite a bit more expensive. The $279 deal is basically the same as the LC-1 (no display), which is only $200 from Innovate. The LCD display they have is extra. The full unit with the display is $400.

right on...I am going to email and make sure I can buy the 279 version and just hook it up to a laptop...

Just realized the $279 version does not include the LCD display... W/the LCD is $399... Back to the LM1 price...

I used the tech article on the Pelican site for making an A/F indicator about 7 years ago and it still works great. It is in our 1987 930 and is handy to tell you if the engine goes lean at full boost. In my race car I use one I bought from Summit Racing. The leds on the home made one in the 930 are more convienent as I have to take more time to actually check the meter and the green/amber/red colors show out of the corner of my eye easily.

thats true, but I just emailed them and it plugs into a laptop and displays realtime.

which works for my needs

It works for your needs, but Innovate will sell you the same thing for $200. The Innovate is also a smaller package, and it's been shown to be sufficiently heat-proof that it can be mounted in the rear trunk (which gets plenty hot). Ask the Zt2 guys what the heat tolerance of their unit is.

Better yet, the slope of the lines on the graph is very heavily temperature-dependant! So when the engine is cold, it may tell you that you're at 14.6:1, and when the engine is warm for the exact same mixture it might tell you that you're at 13.7:1!

Which ain't no way to tune...

--DD

I have the WMS and I like it way better than the LM-1, It uses a better lambda, auto calibrates every time, has a small display with big numbers, you can download it to a PC and will and it will do a simple data log. $400.
http://sdsefi.com/wmsmm.htm

I also have a used NB haltech 30 that I'll sell for $75

Mark,

PM sent about your old one...

I'll give Drew dibs for now at $75 plus $10 shipping

It's a Haltec AF30 narrow band from Gene Berg

Lambda, 30 led reader, Berg instructions and aprox 10' homemade wiring extension.

It needs a 4-prong trailer light connector, a 3amp in-line fuse and a couple of connectors, plus some simple wiring to make it work. I stole that part (homemade) when I did my FI system. It worked fine last time I used it, spring last year.

I'll post pics tonight...camera is in wife's car.

That said... now that I have a WB I'd never use (or buy) a NB again. But I did tune 50+ engines with it and never blew one up.

So, understanding that these wide band sensors cost some $$, what makes up the bulk of that cost? Is it the sensor or the rest of the bits (display, etc)?

I understand that wide band sensors are being used in OEM applications and I may be able to free up a few from their resting places.....

I already have data logging and I'm wondering if I can just connect a wide band oxygen sensor to my data system.

The sensors are cheap ($40), so buying junkyard parts won't save much here. The VW part number for the Bosch LSU4 sensor is 021-906-262-B.

The expensive part is the control and calibration electronics, which are not trivial to design. The Megasquirt guys looked into putting together the wideband controller electronics, but that ended up on the back burner when relatively cheap ($150, Innovate LC-1, or $200 with a sensor and a weld in bung) no-display controllers became available.

If even the Megasquirt guys are deciding it's cheaper to buy than build, you're not going to do a whole lot better. 10 years ago, this stuff was a LOT more expensive, like $900 for a basic setup...

Long term, it's probably better to get an LM-1.
Here's a cheap DIY narrow band link:

http://www.scirocco.org/tech/misc/afgauge/af.html

Pat

Interesting... I wasn't thinking junkyard parts. I was thinking new parts.

I don't need control electronics, just information about the mixture. I just need to talk to my calibrator buddies and see if I can get a curve that translates what the O2 sensor is telling me.

Buy an LC-1. I got mine from DIYautotune.com

http://www.pelicanparts.com/bmw/techarticl...uel_monitor.htm

build this and you are set. add a numerical scale.

enjoy!

The sensor, by itself, tells you nothing. It REQUIRES control electronics to work at all. It's nothing like the simple narrowband sensor.

It's just a sensor. You supply a voltage and it supplies a voltage that's related to the mixture by a calibration curve.

The control part is to give an input to a fuel injection computer.

This is only my understanding and it is obviously at odds with your understanding. I could be wrong... been wrong before, but I've got some notes out to some engine calibrator buddies of mine to see.

Maybe you've got some more detailed information to share about the differences.

I like to save a buck but when it comes to a big buck engine I can't understand why someone would cheap out on a A/F meter.

You screw up and you could fuch your engine.
All for a couple hundred bucks or less....

Stupid is as stupid does....

Plus it only took 5min to wire my WB...well with welding the bung maybe 15min.

That's the way a narrowband works. It's not the way a wideband works. Google wideband or Nernst cell and read for yourself. For one thing, there's no fixed calibration curve. It needs to be externallly calibrated, and thus can be calibrated for fuels other than gasoline. There's a high-precision heater that needs to be externally driven.

kinda late on this post....

The LC-1 hooks up to laptop as well and is only $200....not only do you save $79, but you are buying from a very well known company that has excellent customer support....

I paid $330 for my LM-1 on evilbay, I like it and it works.
I am using one of the analog out signals to power my lambda brain, it's alot more accurate than the original NB sensor. Not only that, it's programmable to a point in case someone wants to do some fancy stuff with it.

just adding my experience too.
not commenting about the opinions others hold.

but I'm running the LC1 with the XD16 (innovates read out guage you can mount on the dash)

a couple of weeks ago I tuned a pair of MPS' for my street car.
and will be using it for the race car in future races.

The wide band is amazing.
I ran narrow band on my old race car for about 4 years.
I feel so much more comfortable about the data that I am now getting.
the XD-16 is pricey.. but VERY cool

I'd never go back the Narrow Band
the $200 LC1 price includes an $80-90 bosche sensor plus bung.
making the cable itself very cheap if you think about it

brant

I wouldn't consider it cheaping out on an A/F meter. With an LC-1 you program the output curve anywhwere. Using the LM3915 led bar driver you know exactly the delta between segments. Use a cheapo variable power source and multimeter to verify operation. Once its built its built. The only A/F gauge I would trust that actually tells you AFR numbers and not just lean/rich is the Innovative XD-16.

Buy the LC-1, you get two analog outputs, digital output for the XD-16. Build or buy an inexpensive gauge and add numbers to it, calibrate it yourself. If you want to use the LC-1 temporarily just for tuning then just watch the output on your laptop via serial connection and logworks software.

For our engines AFR is only 1/2 the battle, if you are doing your own tuning make sure you have dual head temp sensors as well.

Hey Drew,
I was just looking over the schematics for the FI brain and noticed that the manifold temp sensor works in conjunciton with the MPS. It determines the current to part of it. So, you may want to look at your MPS as a possible cause/conspirator for your poor running problem.

(Sorry, couldnt find your original post)

Good day all. So you want to build your own AF meter, or perhaps you want to purchase something pre made. Here is your one stop shop. This product is very versatile. PC hook up, data logging and every type of display you can think of. Post comment please as I am interested in what the non-club has to say about this product.

AF meter

That's the Tech-Edge people. A few people have tried their stuff, and it appears to be decent. Their LM-1 equivalent is about $360US v. $399US, though I wonder if shipping won't eat up a good portion of the savings (they're in Australia). You can buy kits from them, and save a few bucks.

I am using an older 2A0. I built it from a kit. I had to replace the microprocessor a few weeks back because the old one got flakey (might have been due to a bad voltage reg I had on the car). For a while I thought I was going to have to toss the whole thing and start over. I have been using it off and on for about 2 years now. If I was going to start over I'd probably get the Innovate LC1.

I have a Tech Edge 2a0, and 2e0. along with the new LD02 display. I have compared the output of the Tech Edge stuff with our Motec and FJO WBs (both of these units have the NTK sensors, mucho dinero). The readings from the Tech Edge stuff is spot on with the Motec and FJO


Also shipping was not bad.. IIRC about $15 , and I got my stuff within 10 days of ordering

If you are buying a gauge type wideband you should look for one that can display AFR readings from the wideband and give an output for a narrowband reading. This way you can run in closed loop when you have a setting you like. Of course this will only apply if you run fuel injection.

I would buy an Innovate box with the readout. This way you can take it to different cars with minimal changes.

Actually if you are using Megasquirt you want a wideband output. I'm sure most other modern EFI setups are like that too. You want a voltage from 0-5V that corresponds linearly with a range such as 9:1 to 20:1.

Many stock computers are configured for a narrow band sensor. Having a narrowband output will allow you to run one sensor.

The Tech Edge 2A0 has both.

If I were going to do it all over again I would probably get the LC-1 and the fancy display. The LC1 seems like a more rugged/robust unit, even though it is not user servicable.

I definitely would never buy a narrowband unit, especially for an aircooled engine. I think they are almost totally useless, especially now that WB setups are getting cheap. The basic tech edge 2A0 was well under 200 for everything in kit form.

The nice thing about my setup is that I have a nice big LED readout of AFR on the dash. It helps during tuning and also is a nice indicator of any sudden gross problems with the injection.