Difference in AFR readings
10 April 2010, 04:12 AM
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Difference in AFR readings
I have been using a LM-1 for my AFR's with the tail pipe clamp for datalogging On tick over I was getting a perfect 14.7 AFR and richening to low 11's on WOT.
I recently got the knock detection kit from Phormula so I can do/learn how to tune myself (with SimTek). I got a bung fitted into the downpipe so I could pernamently have the LM-1 wideband fitted. After doing a free air calibration and fitting the the sensor into the downpipe and doing some datalogging the AFR on tick over is 13.8 and low 10's on WOT.
I knew it would read slightly different as there is no longer a resonator and silencer before the sensor but didnt expect it to be such a difference!
Has anyone else had this much of a difference from different sensor locations?
I recently got the knock detection kit from Phormula so I can do/learn how to tune myself (with SimTek). I got a bung fitted into the downpipe so I could pernamently have the LM-1 wideband fitted. After doing a free air calibration and fitting the the sensor into the downpipe and doing some datalogging the AFR on tick over is 13.8 and low 10's on WOT.
I knew it would read slightly different as there is no longer a resonator and silencer before the sensor but didnt expect it to be such a difference!
Has anyone else had this much of a difference from different sensor locations?
10 April 2010, 09:47 AM
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Pete,
why don't you just send Michael an email. just because you are now in Oz doesn't mean he cannot give you advice. you might not get it "tout de suite" but when you get it at least you know the advice will be sound.
why don't you just send Michael an email. just because you are now in Oz doesn't mean he cannot give you advice. you might not get it "tout de suite" but when you get it at least you know the advice will be sound.
10 April 2010, 10:40 AM
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If you are using a tail pipe clamp, it's quite common to get a leaner than true reading on your WB at tickover, as fresh air is circulating into the tail pipe, as well as exhaust gasses being expelled. - Different designs of tailpipes can show different margins of error
As soon as you increase RPM from idle (and the gas throughput), your reading should be quite accurate, although slightly delayed
If you are using the Innovate clamp, then you may see up to 1.5 AFR difference running it in the tailpipe (at idle) - Try making your own sensor clamp, that sits further into the exhaust, for better results - I think there's some instructions to make one on the Techedge Website
I personally find it easier and more accurate to tune at low load and Rpms with the sensor in the Down Pipe
As soon as you increase RPM from idle (and the gas throughput), your reading should be quite accurate, although slightly delayed
If you are using the Innovate clamp, then you may see up to 1.5 AFR difference running it in the tailpipe (at idle) - Try making your own sensor clamp, that sits further into the exhaust, for better results - I think there's some instructions to make one on the Techedge Website
I personally find it easier and more accurate to tune at low load and Rpms with the sensor in the Down Pipe
Last edited by FB Tuning; 10 April 2010 at 10:43 AM.
10 April 2010, 11:48 AM
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Michael and Stevie help me out a lot when I ask them silly questions! lol
10 April 2010, 11:54 AM
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If you are using a tail pipe clamp, it's quite common to get a leaner than true reading on your WB at tickover, as fresh air is circulating into the tail pipe, as well as exhaust gasses being expelled. - Different designs of tailpipes can show different margins of error
As soon as you increase RPM from idle (and the gas throughput), your reading should be quite accurate, although slightly delayed
If you are using the Innovate clamp, then you may see up to 1.5 AFR difference running it in the tailpipe (at idle) - Try making your own sensor clamp, that sits further into the exhaust, for better results - I think there's some instructions to make one on the Techedge Website
I personally find it easier and more accurate to tune at low load and Rpms with the sensor in the Down Pipe
As soon as you increase RPM from idle (and the gas throughput), your reading should be quite accurate, although slightly delayed
If you are using the Innovate clamp, then you may see up to 1.5 AFR difference running it in the tailpipe (at idle) - Try making your own sensor clamp, that sits further into the exhaust, for better results - I think there's some instructions to make one on the Techedge Website
I personally find it easier and more accurate to tune at low load and Rpms with the sensor in the Down Pipe
The 1.5 difference you say seems very close to what I have got. Just didnt think it would be such a difference!
Cheers
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