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BMW 3-Series (E90 E92) Forum
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Understanding the ignition timing logic (N52/MSV70)
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11-28-2019, 07:05 AM | #23 |
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I looked at the maps and the only useful information I found regarding the above questions is that the maximum knock threshold is 4.41V.
Now I am not sure if the values in knock factor tables show knock thresholds in Volts, there's no unit assigned to these values, and the name also suggests that these are not thresholds but factors. So the logic behind retard calculation might be a little different than I first suspected. |
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11-28-2019, 07:37 AM | #24 | |
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11-28-2019, 09:29 AM | #25 |
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If that's true then I have plenty of headroom for ignition advance.
One thing for people to have in mind is that DME has specific listening window (in degrees) for knock on each cylinder. This window lenght varies from ca. 45 to 55 degrees depending on rpms. If going too hard on ignition advance you may step out of this window and DME will not register knock. |
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11-28-2019, 10:03 AM | #26 | |
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Yes measurement window is a factor but you'll never be under load with that much advance. Under load, Your maps should pull the timing inside the measurement window really quick. This DME constantly adapts the timing, I've run logs at two different times on the same day, different IATs and recorded much different full load timing. It certainly looks like your fuel keeps the engine quiet. What was the outside temperature when you took these logs? |
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05-03-2020, 03:33 PM | #28 |
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It's been a while but I finally managed to flash RSA Delete to my car as well as modified tune for ignition timing.
In the base tune I modified only two ZWGRUND maps - VVT ROZ98 throttled and full load. Looking at the first logs and comparing them with base tune, it's working just fine on my LPG powered N52. I added 5 degrees of timing in the low-mid revs and 3 degrees up top. Car feels a bit stronger. Logged knock values are more or less the same as before so I am very happy with the result Maybe I will compare acceleration times between base tune and upgrade when I have some time. Thanks Rjahl for guiding me! You're the boss. |
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