2005-2014 Mustangs Discussions on the latest S197 model Mustangs from Ford.

A/F Calculation using SCT Data Logging

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Old Jan 18, 2008 | 09:38 AM
  #1  
FenderParrothead's Avatar
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Default A/F Calculation using SCT Data Logging

Happy Friday!

I'm interested in figuring out what my A/F ratio is by utilizing the SCT's data logger - I believe that this can be done. After looking at the properties that I can log with the device, I have a basic understanding of the general "areas" that I want to monitor, but that's about it. I was wondering if anyone on here as done this before and (assuming that it actually IS doable), can tell me what properties I need to log and what, if any, calculations need to be performed on those properties.

Thanks!
Old Jan 18, 2008 | 09:43 AM
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Default RE: A/F Calculation using SCT Data Logging

Your stock O2 sensor is narrow band. Unless youadd a wide band sensor I wouldn't trust the data you get.

Old Jan 18, 2008 | 09:56 AM
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Default RE: A/F Calculation using SCT Data Logging

I notice the stock O2 sensor info tends to be a bit bouncy during steady running but under hard throttle it steadies out and give solid readings.
I'm a bit fuzzy about what the Wide Band system offers, I believe it has finer graduations of translation but the stockers should be able to read a decent range between lean and rich so.............
Saying you can't trust a stock sensor is garbage. If the sensor wasn't doing it's jobthe car would run like A$$

I do know that an O2 output of 850mv = an A/F of 11.5

Some good info here:

http://www.unofficialbmw.com/all/eng..._o2sensor.html

Old Jan 18, 2008 | 10:02 AM
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Default RE: A/F Calculation using SCT Data Logging

ORIGINAL: marcuskeeler

I notice the stock O2 sensor info tends to be a bit bouncy during steady running but under hard throttle it steadies out and give solid readings.
I'm a bit fuzzy about what the Wide Band system offers, I believe it has finer graduations of translation but the stockers should be able to read a decent range between lean and rich so.............
Saying you can't trust a stock sensor is garbage. If the sensor wasn't doing it's jobthe car would run like A$$

I do know that an O2 output of 850mv = an A/F of 11.5

Some good info here:

http://www.unofficialbmw.com/all/eng..._o2sensor.html

I never said the stock sensor is not doing it's job. The job of the stock sensor is to tell the ECM if your car is running above or below optimum AF ratio. It's job is not to report a full range of AF ratios to a meter or monitor.

Some better info on the differences between a wide band and narrow band here:

http://www.gmtcny.com/WBO2S.htm

Old Jan 19, 2008 | 06:54 AM
  #5  
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Default RE: A/F Calculation using SCT Data Logging

*bump*
Old Jan 19, 2008 | 07:09 AM
  #6  
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Default RE: A/F Calculation using SCT Data Logging

Install a wideband, connect the analog output of the widebandtoyour SCT via their cable end and log A/F with your SCT. You can find the cable end on the SCT website.
Old Jan 19, 2008 | 07:42 AM
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Default RE: A/F Calculation using SCT Data Logging

ORIGINAL: GrayPony

Install a wideband, connect the analog output of the widebandtoyour SCT via their cable end and log A/F with your SCT. You can find the cable end on the SCT website.
+1
The SCT has an input for WideBand A/F.
Old Jan 19, 2008 | 09:26 AM
  #8  
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Default RE: A/F Calculation using SCT Data Logging

ORIGINAL: marcuskeeler

I notice the stock O2 sensor info tends to be a bit bouncy during steady running but under hard throttle it steadies out and give solid readings.
I'm a bit fuzzy about what the Wide Band system offers, I believe it has finer graduations of translation but the stockers should be able to read a decent range between lean and rich so.............
Saying you can't trust a stock sensor is garbage. If the sensor wasn't doing it's jobthe car would run like A$$

I do know that an O2 output of 850mv = an A/F of 11.5

Some good info here:

http://www.unofficialbmw.com/all/eng..._o2sensor.html

You can use that as a Rough estimate, but thats all. Every car will not read the same. Age of the O2 will affect its output, etc.

Casey
Old Jan 19, 2008 | 09:31 AM
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Default RE: A/F Calculation using SCT Data Logging

I have a question relatingto this topic.

My O2 sensors are turned off in my tune. Does this mean they are not actually reading anything, or that the tune just makes it so the CEL doesn't come on (O/R pipe...).
[/align]
Old Jan 19, 2008 | 09:51 AM
  #10  
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Default RE: A/F Calculation using SCT Data Logging

ORIGINAL: sailing220

I have a question relatingto this topic.

My O2 sensors are turned off in my tune. Does this mean they are not actually reading anything, or that the tune just makes it so the CEL doesn't come on (O/R pipe...).
[/align]
Off =s off



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