Nistune Forums

I'm getting a bit confused about the access (range) of each TP Load Cell.

So looking at below picture is it correct to assume that:

Cell zero (12) covers 0-12
Cell one (17) covers 13-17
Cell two (20) covers 18-20
Cell three (27) covers 21-27

And so forth?

Cell ranges are rounded for display

0-12 will fit in cell 0 (12)
13-14 will interpolate to cell 0 (12 cloest)
15-18 will interpolate to cell 1 (17 cloest)

While one cell is highlighted in Nistune but the ECU will take the two closest cells, and average them based on the 'closeness' percentage to each cell

Thank you
I'm not sure I completely understand the logic.

Is there a document detailing how the final timing value is calculated?
I had a look at the documentation but didn't find anything about it.
(maybe I overlooked it?)

For example if I'm at TP17, shouldn't it interpolate between cell 1 and 2 because we're at the end of cell 1?

Also I was thinking since you have all the math in place couldn't you plot a higher resolution map with the interpolated values displayed?
I think that would help to get a better understanding of ones map,especially when you have larger TP spacing ...

So if one TP cell is 80 and the next 90 plot all cells between with interpolated values.

Hope that makes sense?

Actual timing numbers from Nissan Consult are calculated from your ECU and passed to the Nistune (or other consult software). The details on the calculations themselves are not covered by the tuning documentation, as "interpolating between cells" should be necessary enough without going into the maths behind the interpolation

My previous forum post covers how the interpolation is calculated on a 2 cell map. With a 4 cell map it will calculate the percentage of the RPM and load refrence in relation from each cell, and use this to interpolate a final result based on this percentage using value of each of the four cells. Nistune for a timing map will highlight the four cells, and then also highlight (different shade grey) the closest cell

If you are at TP 17 it will only use Cell 1, If you are at TP 16 then it will use a small amount from Cell 0 and the rest from Cell 1. If you are at TP 18 then it will use a little from Cell 2 and the rest from Cell 1

Thanks Matt,

That makes it clearer.

It would be nice to plot a higher resolution map based on smaller TP steps than the map provides.
(for illustration purposes and based on ECU interpolation)

What do you think?

The best way would be to cover between the cells using ratio of adjustment between two cells. Somehow float a cursor over the grid but not sure how to implement that and for what gain?

It's just an idea ..

I read many posts here from people being confused about the actual timing figures they see when doing a log.
Some of it pertaining to knock retard, others because of interpolation.

To avoid this it would be nice to have a visualisation (plot) of interpolated timing values.
That is the timing I will see between TP /RPM load cells.

So for example for below map
it would show TP 12, 13, 14, 15, 16 .. 88 with their corresponding timing values.
The RPM axis would need somewhat higher resolution for that as well.

It's far from a top priority ...

That would require massive maps and I don't think it would make things clearer.
Some might even be confused and think they can edit cells that are not actual cells in the real map.

Other tuning software sometimes use a slightly different map tracing approach by using a cross-hair and a fine line drawn in the map.
The position of the cross-hair or trace-line makes it more clear what adjacent cells are used for interpolation.

Hi Eric,

Yes, it would be a big map,
Your recommendation sounds more practicable ..

I will have a look at a few logs of mine and see if I can plot a map in Excel based on actual timing.

Cheers

Yes a cross hair or ghost cursor would be nice, if I can put it over the existing map

Very good question Torque.

As i am new to tuning and nistune a lot of things are hocus pocus to me. I am following a training @ HP Academy and that made a lot much clearer.

When scrolling through all the maps/scalers a lot of questions came up. So with this post one question answered.

Thanks