desperado Posted November 18, 2004 Report Share Posted November 18, 2004 Picked up used A/F gauge tonight that the guy was having problems with. For $10 I figured I would chance it. I got it fixed. But then finding out what made it tick, I felt robbed again. A/F gauges are basically a volt meter, but I never realized how simple the circuit is. There is abot $10 bucks in parts in a A/F gauge. a chip (LM3914) 3 resistors, a diode (protection for being hooked up backwards) and a capacitor. Oh, and a LED array (bar graph). Just goes to show you that expensive don't necessarly mean complex. Quote Link to comment Share on other sites More sharing options...
el aguila Posted November 19, 2004 Report Share Posted November 19, 2004 Not to mention reading a stock narrowband O2 sensor is worthless. Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted November 19, 2004 Report Share Posted November 19, 2004 Originally posted by el aguila: Not to mention reading a stock narrowband O2 sensor is worthless.not completely, but getting there... Now if you drive a 1.5 VEX, or a new VW, then reading your stock O2, ain't so worthless smile.gif Quote Link to comment Share on other sites More sharing options...
smokin5s Posted November 19, 2004 Report Share Posted November 19, 2004 dude, make them and sell them for 25 bux.... make yourself a quick 15 dollars per pop. Quote Link to comment Share on other sites More sharing options...
Mallard Posted November 19, 2004 Report Share Posted November 19, 2004 October 2004 Grassroots Motorsports has a great article reguarding narrow vs wide band A/F gages. The narrow bands are shit. Never accurate, not repeatable, and impossible to tune from. Hooking an a/f gage to a narrow band and tuning from it is like tuning with a GTech. Quote Link to comment Share on other sites More sharing options...
desperado Posted November 20, 2004 Author Report Share Posted November 20, 2004 Mallard, that ain't funny. I have a Gtech. And you have to remember I am tuning a carb, not EFI.Once it's close I can tune from the plug color, I figure that it's good enough for that. Something I am curious about though. I have seen widwband gauges for sale. Is it the gauge, or the sensor that makes it wideband? Quote Link to comment Share on other sites More sharing options...
Mallard Posted November 20, 2004 Report Share Posted November 20, 2004 It's the sensor. Think of the narrow band as a switch that can tell you if you're rich or lean. It's only "accurate" for A/F's between something like 14.2:1 and 15:1. And even then GRM could not get repeatable results. The wideband, however, returns accurate and repeatable results from 10:1 to something like 16 or 18:1 (Farther out then you'll ever need it). Since most people tune for AFR's around 12.5:1 there is no possible way to tune with a narrow band. If anyone wants to see the article I can probably scan it and post it next Wed or so. (When I'm back on cable). Quote Link to comment Share on other sites More sharing options...
BiG BeN Posted November 20, 2004 Report Share Posted November 20, 2004 Originally posted by desperado: Mallard, that ain't funny. I have a Gtech. And you have to remember I am tuning a carb, not EFI.Once it's close I can tune from the plug color, I figure that it's good enough for that. Something I am curious about though. I have seen widwband gauges for sale. Is it the gauge, or the sensor that makes it wideband? the guage and the sensor are dirty cheap, what makes it wideband is the box that crunches the data.(sometimes incorporated into the guage) Quote Link to comment Share on other sites More sharing options...
Mallard Posted November 21, 2004 Report Share Posted November 21, 2004 Originally posted by BiG BeN: the guage and the sensor are dirty cheap, what makes it wideband is the box that crunches the data.(sometimes incorporated into the guage)True. Your standard ECU may need a narrow band signal so you could either weld a second O2 bung in the exhaust or put a wideband in place of the stock O2 and use one of those 'boxes' that can output a narrow band signal to your ECU. Also, some of those systems can data log so you don't have to drive while watching a gage. Quote Link to comment Share on other sites More sharing options...
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