WBO2-Tuning Spreadsheet

[dave w]

Question:

All of the changes made to the Open Throttle VE table were a reduction in VE, as I would expect based on the rich AFRs during the capture of that particular log. However, there are 3 cells in Idle VE table that were modified by the spreadsheet that were all an increase in VE.... Two cells in particular, that are the same RPM and KPA between both tables, cells were increased in the Idle VE table, and, decreased in the Open Throttle. Possibly a spike of irrelevant data causing the discrepancy?

Welcome to the complex world of tuning. Change parameters, and see what happens in the spreadsheet (that's tuning). Typically increasing a VE cell value will lower AFR (richer). Typically decreasing a VE cell value will increase AFR (leaner). It's a good plan to have at least 5 data points (counts) in a VE cell, before making changes to the VE cell. It's a good plan the "Smooth" peaks and valleys in the VE Table.

Stating the obvious:
An engine requires less fuel at low RPM's and light engine load.
An engine requires more fuel at high RPM's and heavy engine load.
An engine needs more fuel to accelerate to 70 MPH, yet an engine needs less fuel to maintain 70 MPH once it achieves 70 MPH.

The VE Table is 3 dimensional, Load / Fuel / RPM, understanding the three statements above is 3 dimensional thinking.

dave w