Quote:
Originally Posted by toddu
You can see below it's for about a second. Is this a problem? The graph below is zoomed into just one part of the graph. But, it's similar pattern through the gears. I'm not sure if that's the accelerator pump kicking in. Todd
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Todd,
Does the software that you are using with the wideband provide a smoothing feature, and if so have your smoothed the AFR any in the posted graph?
The Innovate LM2 "Logworks" software that I used has an adjustable smoothing feature that you can apply to take out the high and low peaks, which helps to see what the AFR looks like over few seconds vice within a second or two. I would have been chasing my tail if I tried to adjust my AFR based on the un-smoothed data.
I ended up applying just enough smoothing to take out the 1-2 second AFR spikes. Not sure if this is acceptable though. With the smoothing on, my graphs turned out similar to most fuel injected AFR graphs that I found, without smoothing my AFR was all over the place
Unfortunately, there isn't a lot of Porsche carb AFR graphs around (believe me, I looked - I can post links to the one's I found if you are interested).
As such, I'm not sure what you should expect regarding momentary spikes (lean or rich, lasting 1-2 seconds). I spoke to Richard Parr about it (I was lean on acceleration) - although I didn't get a specific answer, I came away with the understanding that a 1-2 second spike was normal.
BTW - I did most of my runs 2k RPM up in 2nd or 3rd gear Not sure if this is right either, but I recall finding that this recommendation somewhere.
Bottom Line - My Take on Your AFR Graph: you appear to be lean during the time period 111.7s to 114.0s or from 2.3K RPM up. Smoothing would probably show this averages out to ~ 14-15 AFR for ~ 3 seconds. As such, I agree with Steve (which is always a safe bet...) - you appear to be lean.
If you could, I think it would be helpful if you could post a graph that shows your AFR over a longer time period/duration. Tough to do - I had to find some remote roads where I could stop and then wind up to 80 mph or so...
Good luck,
Gordo