Dyno A/F ratio is weird.....
08-27-2006, 06:52 AM
#1
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Dyno A/F ratio is weird.....
Guys,
Just got my car dyno'd yesterday and put down decent numbers but my A/F ratio (on the right) is all over the place.....
I only have intake/exhaust and wonder what's causing all the spiking and inconsistency?
Just got my car dyno'd yesterday and put down decent numbers but my A/F ratio (on the right) is all over the place.....
I only have intake/exhaust and wonder what's causing all the spiking and inconsistency?
08-27-2006, 03:16 PM
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After looking at the dyno chart you had posted it looks correct.
the wide band O2 they used might not be reading correctly or it might be sending false inputs but it registers correct numbers.
I am assuming that it was a sniffer wide band 02 which was attached on the exhaust tip?
Usually the wide band is attached in place of the 2nd 02. Basically disconnect the 2nd 02 sensor and install the Wide band thats how i have always done it in the past of my Audi/VW/BMW tuning days.
the reason could be the inconsistent flow of the exhaust depending how far in the sensor was shoved in the exhaust pipe.
but my interpretation of your graph is this...
RPM A/F
4200 13.0
4500 13.5
5000 14.4
5500 13.0
6000 14.2
the engine has been known to have a flat spot @ 5-6K this is where it tends to bog. Thats the reflection of your A/F going rich then leaning out when Vtec kicks in.
HP numbers are with in range i just think the A/F was not measured correctly or the sesnor was not gettign a steady stream of exhaust causing the inconsistent chart.
the wide band O2 they used might not be reading correctly or it might be sending false inputs but it registers correct numbers.
I am assuming that it was a sniffer wide band 02 which was attached on the exhaust tip?
Usually the wide band is attached in place of the 2nd 02. Basically disconnect the 2nd 02 sensor and install the Wide band thats how i have always done it in the past of my Audi/VW/BMW tuning days.
the reason could be the inconsistent flow of the exhaust depending how far in the sensor was shoved in the exhaust pipe.
but my interpretation of your graph is this...
RPM A/F
4200 13.0
4500 13.5
5000 14.4
5500 13.0
6000 14.2
the engine has been known to have a flat spot @ 5-6K this is where it tends to bog. Thats the reflection of your A/F going rich then leaning out when Vtec kicks in.
HP numbers are with in range i just think the A/F was not measured correctly or the sesnor was not gettign a steady stream of exhaust causing the inconsistent chart.
08-27-2006, 03:57 PM
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it could be a bad dynapack? i have seen 3 shops attend a VW/Audi show they all brought their dynapacks and each one was off any where from 10-15.
maybe this dynapack is showing true numbers and you have to apply the 0-15% drive line loss to get crank HP??
Bottom line i am not a fan of the Dynapack, Mustang, Dynojet, Maha are very reliable and accurate.
maybe this dynapack is showing true numbers and you have to apply the 0-15% drive line loss to get crank HP??
Bottom line i am not a fan of the Dynapack, Mustang, Dynojet, Maha are very reliable and accurate.
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08-27-2006, 08:57 PM
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Thanks guys.
No correction was done to the numbers. Please keep in mind that this is 95F summer weather so I'm happy I'm even over 200hp.
The wide band sensor was clipped onto the exhaust tip so that must be why the A/F graph looks so out of wack then......now I can sleep =)
I can't imagine the exhaust/intake losing power thou...i know the ARC don't add power but the amuse losing power seems odd....
the car drives fine thou so i'm happy =)
No correction was done to the numbers. Please keep in mind that this is 95F summer weather so I'm happy I'm even over 200hp.
The wide band sensor was clipped onto the exhaust tip so that must be why the A/F graph looks so out of wack then......now I can sleep =)
I can't imagine the exhaust/intake losing power thou...i know the ARC don't add power but the amuse losing power seems odd....
the car drives fine thou so i'm happy =)
