Originally Posted by FlyingFinn
I guess in this case "one picture is worth about million words".
With all the talk in this thread, lot of it quite vague and rather marketing like, this picture from Roger is the best and most clear demonstration of what a -20deg IAT offset really does!
I was always little annoyed that none of the various IAT offset device vendors on this forum never provided a plot like this.
Actually showing what their product does.
Instead everyone resorted to providing a lengthy verbal infomercial.
These plots were taken over my test ride course with the Motronic reset and the O2 sensor unplugged so there were no Adaptive Values to confuse things. It's interesting in the upper plot to see that it's leaner than 14.7:1, due to the 4% leaning effect of the E10 I run. But as you say the shift is clear, especially so in the little histogram plots.
After you close the loop, this is a much more difficult effect to demonstrate.