DIY air/fuel ratio meter

[lancerevo]

Hi

Is there a way to make a DIY air/fuel ratio meter. I was wondering if I can buy a small LCD volt meter that reads from 0.01v to 0.1v dc to read the a/f ratio. Does anyone have tried it? Or is there another way? I can buy a gauge but I prefer to make it myself...

Thanks

[iceracerdude]

Yes I've found that there are plans to make an air/fuel
gauge for about $40 bucks!
But then you can buy them new for starting at $25...

[Gforcefd]

but those air fuel gauges that cost $25 bucks are not a really good idea, they only measure if your in a very narrow range, but if you going to do any kind of performance stuff with your engine you really need a wideband. Zeitronix makes a really nice one but your looking at $300+ for the setup.

[CharlieZ]

lancerevo:
What plan are you using?
This? http://www.scirocco.org/tech/misc/afgauge/af.html
Here's a kit ou can buy: http://www.impconcepts.com/airfuelmeterforsale.htm

[FestYboy]

your range should be 0.1-1.0 VDC not .01-.1

[lancerevo]

"your range should be 0.1-1.0 VDC not .01-.1" Sorry. You are correct. My mistake.

[CharlieZ]

"your range should be 0.1-1.0 VDC not .01-.1" Sorry. You are correct. My mistake.

In the U.S. we have Harbor Freight. Digital multimeters as low as $3 on sale. $5 not on sale.
They operate on a 9 volt battery. Using the 2000 millivolt range, one of these might do the job for you.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90899

[lancerevo]

I have bought a volt meter that reads 0-2v. It have worked very well. My engine is running lean after 4000rpm at wot in say, 3rd gear. I have rotated the vaf wheel and changed the setting for the flap to make it richer. It worked but now I saw a decrease in fuel economy

[bhazard]

Narrowbands are pretty much for looks.

[Roboskittle]

If you want a narrowband that bad ill sell you mine for 20 shipped lol. They are for looks and are completely worthless though.

[FB71]

https://www.14point7.com

[bravekozak]

Stoichiometric Air/Fuel Ratio of Common Fuels
Gasoline(Petrol) = 14.7:1
Methanol = 6.4:1
Compressed Natural Gas(CNG) = 17.45:1
Diesel = 14.5:1
Nitromethane = 1.7:1 (Stuff used in top fuel dragsters)
E10(10% Ethanol, 90% Gasoline) = 14.13:1
E15(15% Ethanol, 85% Gasoline) = 13.8:1
E85(85% Ethanol, 15% Gasoline) = 9.7:1
Ethanol(E100) = 9:1 (Alcohol)

"From the factory, most vehicles (like: BMW, AUDI, Mercedes, VW, Toyota and mostly Japanese brands ) are pre-set to 14.3 to 14.7 parts air to one part fuel (but physically it is known, that one part of fuel need 20 to 24 parts of Oxygen, not the air, that means that for the optimal combustion the fuel/air ratio must much higher!). While is this 14/1 air to fuel a fine ratio for emissions...? For sure NOT! the best ratio for fuel economy is significantly higher. Technically speaking, the higher the A/F ratio the better your fuel mileage, but most cars can only handle about 16:1 before overheating or engine damage as follow. The optimal ratio is 24++ parts of air (at least) to 1 part of the fuels like gasoline (petrol), ¬ for diesel even higher!"

[russian]

You probably want a wideband, right?

The deal with wideband is that you need a processor to control the heater - the processor reads sensor temperature and heats it up accordingly. There is a number of open source designs for software and hardware, but that's a bit more complex then soldering five resistors together. Given all this, a $50 Bosch sensor and a $50 controller with a small LCD is a great deal