Like others I am very interested in this and it may be also worth some time trying to calibrate this on my vehicles and recalibrating the VQ map properlyin a 3" tubing, it can read to "700RWHP" as stated on VMP site. I'm at a peep more than half of that @ the wheels @ 16PSI. They said the resolution wasn't good enough for the MAF to be utilized perfectly.
ie: Problem was it being too rich in the higher rpm/load, but they scaled it enough to make it better. Any suggestions would be awesome though!
The main issue is that Nissan has a 64 point VQ map which matches load to voltage. The VMP calibration tables provided contain less than half of these points, so there was not enough resolution provided
I took the provided table and doubled the size of it and then interpolated the mid points, but still left the table short of the full 64 points (by about 12 or so) so then filled points at the start. It may be that this table needs to be shifted left if you are reading lean
Really I should be expanding this table out further using some better method of filling out the interpolation points (say every 12 points adding an extra mid point rather than all at the start)
What this means is that at X voltage read, it is not reporting enough load to the ECU. The tuner should then adjust the VQ map by cutting from about say start 10 cells in and move that to the start and then fill in the end with max value (65535)
This will make the VQ map report more load for the read in voltage and then you will read further right in the fuel maps and get better AFRs
