Air/FUel guage usefulness
- Thread starter Tito1
- Start date
K
Keith@FP
If your car has been properly set up - which is done with an a/f gauge, by the way - you don't need it. It's like a boost gauge in that regard. But if you're just screwing around with the turbo on a MSP, you really should at least check that you're getting reasonable a/f ratios. Skipping that means you're gambling with your motor. Since the only reason I can see for not checking the a/f ratios is to save money, it's false economy.
Keith
Keith
K
Keith@FP
It won't necessarily add the fuel you need. After all, you make power by burning air and fuel. If you just add air, you need more fuel. Timing does also need to be addressed.
Keith
Keith
WeldingHank
Member
- :
- 1989 Ford Probe GT
the thing with most A/F guages is that they can pretty much only tell you yes or no. yes your rich, or NO!! your too lean. with narrow band O2's (what most vehicles are equipped with) it can tell you lean or rich and thats it. it can't really tell you how lean, or how rich. it can tell you your rich, but rich could be 11:1 - 8:1 A/F ratios. same for the lean side. but it IS a good indicatior if you are lean enough to do damage.
Have any of you guys seen or used the Ai/fuel guage put out by dawes devices...it uses led lights to indicate lean or rich...I've been trying to get some opinions on this guage for a while, but no one else is interested I guess.
www.dawesdevices.com/airfuelmeter.html
But it seems like a practical and inexpensive way to watch the fuel mixture.
Ilan
www.dawesdevices.com/airfuelmeter.html
But it seems like a practical and inexpensive way to watch the fuel mixture.
Ilan
K
Keith@FP
Most a/f gauges do use a few LEDs to indicate the mixture. But as ARunto said, they're limited by the accuracy of the sensor itself. They can be tuned to get you into a safe zone, but they're not accurate enough to maximise power. The further you are from stoich, the less accurate they are.
Keith
Keith
K
Keith@FP
Sorry, that wasn't clear. The gauges can be used to help you tune the car to a safe level, but they're not accurate enough to maximise power. The gauges don't do anything but tell you the ratios. The actual tuning is done with something that controls fuel.
Keith
Keith
Keith@FP said:
I'm sorry, but I have to step in here.
A stock narrowband O2 will pretty much show you two settings. Lean OR Rich.
Here's a comparision from:
http://www.plxdevices.com/M-Series_productinfo.htm
Narrow:
Wide:
If they don't show, then just click on the link above.
As you can see, the Narrowband is pretty much an on/off switch.
The wide band gives you very good resolution.
I don't see how the comment "a narrowband with an a/f is good for tuning" is true????
I run one of these:
http://www.innovatemotorsports.com
With a Bosh LSU 4.2 pre-cat in the RX8.
Here's a sample for you armchair tuners:
I'd rather have that, than an on/off switch. Also with the LM1, you can add other sensors and graph with everything, or output ot an excel spreadsheet and graph from there.
I'll be tapping in some sensors and then aggressively tuning the 8 very soon.... but I now have baseline maps.
You can also read more on Bosch Oxygen Sensors here:
http://www.boschusa.com/AutoOrigEquip/Gasoline/ExhaustSensors/
Bosch also shows you the diff between a narrow band and a wide band on their site.
LSF 4 is narrow
LSU 4 is wide
http://www.boschusa.com/AutoOrigEquip/Gasoline/ProdExhSensors/
K
Keith@FP
First, please don't make up quotes for me. I never said "a narrowband with an a/f is good for tuning".
I said it can be used to get a car into a safe zone. We along with the rest of the tuning community did this for years before the widebands became freely available, although we did have a wideband on our inhouse dyno. We also use widebands on all of our turbo cars here. I don't need an education in how they work.
Your big graphs are exaggerated. Not surprising given the source - a supplier of wideband sensors. The Bosch automotive handbook shows that there is still a voltage differential in the output of a "narrowband" up to about 0.8 lambda where the graph cuts off. Depending on the fuel used, that's somewhere around 12.5:1 or so. Certainly not as dire as the 14.2:1 flatline indicated on the biased graph above. It takes a display with more than a couple of LEDs to show this however.
I do prefer widebands if they can be fitted and the prices are now getting into a reasonable range. There's no question they are superior. But given the choice between an a/f gauge running off a narrowband sensor and no a/f gauge at all, it's a pretty easy choice. That was my point.
Keith
I said it can be used to get a car into a safe zone. We along with the rest of the tuning community did this for years before the widebands became freely available, although we did have a wideband on our inhouse dyno. We also use widebands on all of our turbo cars here. I don't need an education in how they work.
Your big graphs are exaggerated. Not surprising given the source - a supplier of wideband sensors. The Bosch automotive handbook shows that there is still a voltage differential in the output of a "narrowband" up to about 0.8 lambda where the graph cuts off. Depending on the fuel used, that's somewhere around 12.5:1 or so. Certainly not as dire as the 14.2:1 flatline indicated on the biased graph above. It takes a display with more than a couple of LEDs to show this however.
I do prefer widebands if they can be fitted and the prices are now getting into a reasonable range. There's no question they are superior. But given the choice between an a/f gauge running off a narrowband sensor and no a/f gauge at all, it's a pretty easy choice. That was my point.
Keith
