 Can I make an A/F mixture gauge?, using an O2 sensor and such... |
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| lapuwali |
 Jun 27 2006, 03:02 PM
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#21
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Not another one!  Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743   |
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... |
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| pek771 |
Jun 27 2006, 08:14 PM
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#22
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Member Group: Members Posts: 273 Joined: 23-November 05 From: Conover, NC Member No.: 5,175 Region Association: None 
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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 |
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| groot |
Jun 28 2006, 06:45 AM
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#23
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Dis member Group: Members Posts: 896 Joined: 17-December 03 From: Michigan Member No.: 1,444 |
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. |
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| yarin |
Jun 28 2006, 06:57 AM
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#24
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'14-X'in FOOL Group: Members Posts: 988 Joined: 13-May 03 From: Guttenberg, NJ Member No.: 693 Region Association: North East States |
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! |
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| lapuwali |
Jun 28 2006, 08:39 AM
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#25
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
QUOTE(groot @ Jun 28 2006, 05:45 AM)  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. The sensor, by itself, tells you nothing. It REQUIRES control electronics to work at all. It's nothing like the simple narrowband sensor. |
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| groot |
Jun 28 2006, 08:51 AM
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#26
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Dis member Group: Members Posts: 896 Joined: 17-December 03 From: Michigan Member No.: 1,444 |
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. |
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| Mark Henry |
Jun 28 2006, 09:15 AM
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#27
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
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. (IMG:style_emoticons/default/confused24.gif)
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. |
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| lapuwali |
Jun 28 2006, 09:20 AM
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#28
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
QUOTE(groot @ Jun 28 2006, 07:51 AM) 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. 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. |
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| Mueller |
Jun 28 2006, 09:20 AM
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#29
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None
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QUOTE(drewvw @ Jun 27 2006, 08:25 AM) right on...I am going to email and make sure I can buy the 279 version and just hook it up to a laptop... 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.... |
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| Sammy |
Jun 28 2006, 01:16 PM
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#30
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. Group: Members Posts: 1,190 Joined: 21-January 03 From: Orange, Ca Member No.: 178 |
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. |
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| brant |
Jun 28 2006, 01:21 PM
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#31
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914 Wizard Group: Members Posts: 11,632 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains 
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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 |
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| yarin |
Jun 28 2006, 01:55 PM
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#32
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'14-X'in FOOL Group: Members Posts: 988 Joined: 13-May 03 From: Guttenberg, NJ Member No.: 693 Region Association: North East States |
QUOTE(Mark Henry @ Jun 28 2006, 11:15 AM) 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. (IMG:style_emoticons/default/confused24.gif) 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. 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. |
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| Dr Evil |
Jun 28 2006, 03:52 PM
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#33
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Send me your transmission! Group: Members Posts: 23,002 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region
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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) |
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| turbo914v8 |
Jun 28 2006, 04:25 PM
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#34
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Member Group: Members Posts: 373 Joined: 26-July 03 From: Canada Member No.: 952 |
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 |
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| lapuwali |
Jun 28 2006, 04:54 PM
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#35
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
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.
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| mightyohm |
Jun 28 2006, 04:57 PM
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#36
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Advanced Member Group: Benefactors Posts: 2,277 Joined: 16-January 03 From: Seattle, WA Member No.: 162 Region Association: Pacific Northwest |
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.
QUOTE(turbo914v8 @ Jun 28 2006, 03:25 PM) 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 |
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| TimT |
Jun 28 2006, 05:07 PM
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#37
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retired Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 |
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 |
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| Brett W |
Jun 28 2006, 05:35 PM
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#38
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Advanced Member Group: Members Posts: 2,856 Joined: 17-September 03 From: huntsville, al Member No.: 1,169 Region Association: None
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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. |
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| mightyohm |
Jun 28 2006, 05:37 PM
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#39
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Advanced Member Group: Benefactors Posts: 2,277 Joined: 16-January 03 From: Seattle, WA Member No.: 162 Region Association: Pacific Northwest |
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.
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| Brett W |
Jun 29 2006, 01:13 AM
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#40
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Advanced Member Group: Members Posts: 2,856 Joined: 17-September 03 From: huntsville, al Member No.: 1,169 Region Association: None
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Many stock computers are configured for a narrow band sensor. Having a narrowband output will allow you to run one sensor.
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