Dyno results: huge lean spike at 3500 RPM with GIAC stage 3- chip
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I had the car dynoed again today. This time boost and air-fuel ratio was measured.
First graph shows HP and torque, second graph shows boost and air-fuel ratio.
<img src="http://pictureposter.audiworld.com/66538/dyno_1.jpg">
<img src="http://pictureposter.audiworld.com/66538/dyno_2.jpg">
See that huge spike in the air-fuel ratio at 3500 RPM, around 18 parts air for 1 part fuel? That's a lot! On another run it spiked all the way up to 22. That's dangerously high, as far as I know...
What's up with that?
It's not a misfire, because there is no power dip in the first graph.
The ratio was measured at the exhaust pipe. I don't think there anything pumping oxygen into the exhaust when the car is fully warmed up, is there?
So I think the ECU programming is to blame.
Any experiences or comments? Suggestions? Thanks.
First graph shows HP and torque, second graph shows boost and air-fuel ratio.
<img src="http://pictureposter.audiworld.com/66538/dyno_1.jpg">
<img src="http://pictureposter.audiworld.com/66538/dyno_2.jpg">
See that huge spike in the air-fuel ratio at 3500 RPM, around 18 parts air for 1 part fuel? That's a lot! On another run it spiked all the way up to 22. That's dangerously high, as far as I know...
What's up with that?
It's not a misfire, because there is no power dip in the first graph.
The ratio was measured at the exhaust pipe. I don't think there anything pumping oxygen into the exhaust when the car is fully warmed up, is there?
So I think the ECU programming is to blame.
Any experiences or comments? Suggestions? Thanks.
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