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Tuning VVE for SD tune

Practical Reflash Tuning

Discussion and questions related to the course Reflashing

Page 1

When you dial in the VVE table do you get every area exactly as what's commanded or do you have some leeway? If not what process do you use to get this perfect? As I find that modifying one area to correct actual vs commanded will alter other areas that are fine when the coeffs are generated. I haven't watched the course yet but am using efi live and wondering if this course will apply to what I'm doing.

There is always some error inherent regardless how fussy you are, and the way the GM VVE tables are generated is that the maths behind the calculation means that the table must maintain a consistent shape in both the load and rpm directions across a single zone in the table. This does affect the ultimate accuracy however in my own experience it's not a real issue. You should be able to get the measured AFR within around 1% of the commanded AFR using the VVE tables. In closed loop we still have the fallback of the STFT and LTFT to correct any remaining error too. I always aim to have any error in open loop/WOT operation to be on the rich side of my target for safety sake.

Since both EFI Live and HP Tuners are still dealing with the GM PCM, our course is still going to be helpful although you're going to need to do apply the techniques in a different way in EFI Live.