Nistune Forums

No since they are different curves. Attached is an image of GTR (red) vs Z32 (purple) MAF curves inside the software

You will note that the GTR VQ map is doubled to represent how it would look when used on a single MAF ECU

The thing to remember here is that
- yellow graph is Volts vs kg/h (maximum load that can be measured)
- VQ map is volts vs ECU TP scaling (0-65535)

Matt wrote:The thing to remember here is that
- yellow graph is Volts vs kg/h (maximum load that can be measured)
- VQ map is volts vs ECU TP scaling (0-65535)

Yep that is clear after your last writh up and I'vr seen that the yellow graph is in kg/h. My thought was, that the small correction for the Nismo afm to the z32 curve goes in direction to the standart curve. Cause the original afm curve is in the graph relativ near to the z32 curve, i thought it could be. But how you said, what you see is only one afm and the values will doubled, just as the difference of the curves.

What do you think is the right way to adjust the afm curve? Maybe set the whole map to afr 12.0 (retard timing a bit to prevent knock) and adjust lantecy, k-value and afm curve until you reach target AFR over the hole map? ...think can be quite tricky.

As i writed, i mapped a rb26det with power fc an nismo afms, tried a few days everything out, re-adjusted afm tables many times, but light partload was allways bad and a waste of time. Car has a big singel throttle, I think Power FC is not made for such a change. No throttle compensation tables, and overall to less correction tables. As longer i work with Nistune and as less bugs it have, as more I like it.

What do you think is the right way to adjust the afm curve?

For the HPX we did a dyno with my Z32 MAF and then got the AFR graph. Afterwards swapped to HPX and then remapped K constant first to get load about right and then VQ map to get the similar AFR graph

I could make sense, that nismo has choised the same curve, that you have only adjust the K-Value?
What do you think about, can it be? Or would i be mistake in suggestion? However i will try it out in the next days...

you might be right on that, I looked at the nissan curves and the nismo curve is very close to being 100% higher flow at all points along the curve over the stock gtr, since it is a linear(or very close to linear) relationship then you can compensate using a single value (i.e. the K constant), if it was not a linear relationship then you wouldn't be able to use a constant to compensate and would require changing the vq map.

So if airflow is ~100% higher at all points then would you change K 100%? (100% more airflow = 100% more pulse width?)

I changed to my nismo mafs this weekend and I kept the stock gtr maf curve and doubled K as a starting point and so far car is running fine, still needs a dyno tune to adjust for the other mods I have added but otherwise its drivable, thought it would be helpful to post my experience

mikeyrhd wrote:I changed to my nismo mafs this weekend and I kept the stock gtr maf curve and doubled K as a starting point and so far car is running fine, still needs a dyno tune to adjust for the other mods I have added but otherwise its drivable, thought it would be helpful to post my experience

Have you also tried to use the z32 afm curve? Would be interessting how the difference is? Sorry we had already snowfall over the weekend in Switzerland. Very very early this year! I have to wait a few days until the streets are free from salt. I will give a feedback over my experience with the nismo afm's.

I didn't try the z32 curve but I probably wouldn't notice the difference at this point because of how close it is and my car needing a proper tune, although at idle I could see needing to have K lower or it would be too rich. I really think that you were right when you said that maybe the stock gtr and nismo maf curves are the same, it would make a lot of sense from nissan engineering point of view being that the nismo's are meant to be direct replacement

must be some super sweet roads to drive on over there! I live in a prarie region so it's pretty boring lol =(