How to build an air/fuel guage

[hacked521]

Build your own air/fuel ratio gauge!

I wasnt sure where to put this, its both engine and electrical so ill just put it in electrical and let the other people deal with it.... build your own air to fuel ratio gauge cheaply, figured that i would put this on here. I havent tried it yet but will give it a go when i accumulate the parts. click the link! I feel that its a good article for anyone with a bit of experience with soldering and someone that doesnt feel like paying a chunk of change just to know their air/fuel ratio. :cool:

[Guest DatsuNoob]

Cool. I was actually looking for this last night. Saturday, I saw almost the exact same how to on that show Trucks, but couldnt find it.

[510goofy]

thats cool thank yo for that

 

 

[bonvo]

i would think it would fit well into the how to section i may have to make me one of these

[freekwonder]

So would this be the equivilant of a wide band or a narrow band a/f?

[Duke]

So would this be the equivilant of a wide band or a narrow band a/f?

 

This is a narrow band gauge. IMO, if one is going to be doing any carb tuning, a wideband is the only way to go.

[72240z]

This is a narrow band gauge. IMO, if one is going to be doing any carb tuning, a wideband is the only way to go.

 

IMHO if your doing ANY tuning wide band is the way to go. Narrow band is just a ball park..... A small ball park lol.

 

I wonder though how accurate it is, the article is saying each bar is a specific A/F in a decent range. It could be helpful if it holds water. I would be interested to hear some peoples experience with it.

[hang_510]

for a few dollar in parts it would compliment the carb sych tool nicely.

 

 

ive been looking at something like this...

[510goofy]

Cool. I was actually looking for this last night. Saturday, I saw almost the exact same how to on that show Trucks, but couldnt find it.

 

 

i know hat you are talking about i cound find nether i look all over ther web site

[datzenmike]

The narrow band only shows a voltage change in an extremely narrow window of 14.7? (w/e) Before and after there is no change, or virtually no change.

 

To register a 12 this must be using a wide band sensor.

 

This:

 

...is almost worthless as it only indicates over, on or under and not by how much. If tuning you need 11-12 richness under full throttle to reduce pre ignition and give best performance..

 

Brian how much is this one and is it wide band?

.

[hang_510]

Brian how much is this one and is it wide band?

$~55, and is wideband

[datzenmike]

 

 

 

Sorry thought I posted the pic... this one.

.

[Datsun fan]

Whats the difference between narrow/wide band, If I know that I can make it cheaper/practical :cool:

[72240z]

Narrow band doesn't usually read beyond 1:5. You need better then that to actually tune.

[72240z]

Check this page out I came across. It's a really good write up in addition to the original post.

http://www.buckeyetriumphs.org/technical/Carbs/AFMonitor/AFMonitor.htm

[Datsun fan]

EFI cars don't have CHOKE,carb cars do, Is there effects such as cold choked engine

start will produce soot and may get stuck on O2 sensor ? O2 sensors and pretty accurate

mV (2 mV sensitivity) meters are really cheap in the place I live, I'm just confused

which O2 sensor do I need for A12 engine .I'm really interested in such project lol

[tlap]

Oxygen sensors put out a 0-1V signal, a narrow band meter indicated from 0-1V. A single wire O2 sensor relies on the exhaust gas to heat it to over 600 deg. I installed a three wire O2 sensor, two of the wires are for the internal heater. They heat up much faster and last alot longer. It is connected to a narrow band meter, agreed that a wide band is better (much more linear), but alot more expensive. The narrow band has worked great for me so far. It showes me when the engine runs rich or lean, combine that information with how the plug look, and jet accordingly. My engine runs 100% better now, than when I was relying on only reading plugs.

Just my $.02

[MAG58]

WBO2's are much different from Narrow Band sensors. Narrow Band O2 sensors just rely on the diffusion of gasses into a measuring apparatus to gauge the amount of oxygen in the exhaust and from there a number can be estimated. Wide band sensors use an electrochemical pump to put measured amounts of gas into a chamber for measuring. This allows them to produce a much more specific oxygen concentration over a much wider interval, thus giving the ability to tune at roughly infinite intervals in the range (depending on sensor resolution). However, what makes them more useful to tuning also makes them more delicate. They are more sensitive to high EGT's and as such is why they're always mounted downstream of the turbo. If you're only trying to tune to 14.7 (Lambda=1.0) than by all means go for the Narrowband. It's cheaper and more rugged. however the majority of us want to tune closer to 11-12 AFR (Lambda=.8) as that's where more safe power is to be had (depending on setup).

 

For those of you looking for the difference in the graphs, I found these on boostsource.com. The 02 graph is well above 1.0V which is why most computers require a WB02 controller, which takes the voltage and converts it to a 0-1V output for the computer to read, and facilitate closed loop tuning.

 

 

This Wide Band graph isn't quite how it really is in real life. A true wideband currently on the market has a graph closer to that of a log function than that of a true linear function. This varies however, and is why it is essential to make sure that you calibrate your WBO2 sensor at the correct intervals.

[Datsun fan]

EFI cars don't have CHOKE,carb cars do, Is there effects such as cold choked engine

start will produce soot and may get stuck on O2 sensor ?

[Sealik]

 

 

 

Sorry thought I posted the pic... this one.

.

 

 

That one, with the kit is 160 bucks. Plus shipping and duty (for me)......ka ching

Been looking around for 1....for my Z24 EFI

 

http://cgi.ebay.ca/AEM-Analog-Wideband-o2-Gauge-Sensor-Air-Fuel-Ratio-/290498605804?pt=Motors_Car_Truck_Parts_Accessories&hash=item43a310f2ec

[Sealik]

Sooooo........if a guy (me) :) needs an air/fuel ratio gauge to get his Z24/200sx EFI set somewhat properly, would 'he' invest in a narrow or wide band? . Other than looking at the plugs and exhaust....one really has no clue on how rich or lean the engine is running. I'm sure the AFM could be tweeked a little better. Do I need the wide band to see what's happening at WOT and or?

Sorry....but I'm not to A/F ratio savvy... :blink: ..yet. :D

Big difference in price.

[datzenmike]

Optimum air/fuel ratio is 14.7 to 1? There abouts. If just tuning for economy then a narrow band is fine as it only indicates when you are spot on for the fuel ratio. If you have the ability to adjust your fuel map (mostly for performance but specially for turbo applications) then a wide band is preferred. Heavy throttle or turbo boost requires a richer mixture to help eliminate pre-ignition. Knowing that you have an air/fuel ratio (AFR) of 12:1 at a certain rpm where it pings means you can program an increase into your system. A narrow band would only be able to tell you when you are at or very near the stoichiometric or perfect AFR of 14.7:1.

 

As a rule the ECU ignores O2 sensor input at wide open throttle (WOT) and falls back on a pre-programed fuel enrichment curve for performance and engine protection.

[Sealik]

Optimum air/fuel ratio is 14.7 to 1? There abouts. If just tuning for economy then a narrow band is fine as it only indicates when you are spot on for the fuel ratio. If you have the ability to adjust your fuel map (mostly for performance but specially for turbo applications) then a wide band is preferred. Heavy throttle or turbo boost requires a richer mixture to help eliminate pre-ignition. Knowing that you have an air/fuel ratio (AFR) of 12:1 at a certain rpm where it pings means you can program an increase into your system. A narrow band would only be able to tell you when you are at or very near the stoichiometric or perfect AFR of 14.7:1.

 

As a rule the ECU ignores O2 sensor input at wide open throttle (WOT) and falls back on a pre-programed fuel enrichment curve for performance and engine protection.

 

 

Thanks Mike....

 

Ya....my system is pretty primitive....no ECU 02 sensor....let alone a turbo :lol:

Think I'll invest in a narrow band.....asap.

 

I know this is a little close to the head and picking up only a 'couple' of pistons.

Think it might work....?.... but not very efficient?

Stick the A/F 02 sensor into the IAS location on my EM

 

[Sealik]

Ya.....I know.....should pull the exhaust pipe and drill a hole for the 02. :)

[datzenmike]

Or.... the Z24i manifold. Comes with an old O2 already installed. Feedback carb manifold should be similar.