Hi to all!
I have tuned my car's ECU myself and everything looks OK; nice power gain, no errors...but, I'm confused with original values in duration map.
The problem is that for values greater than 60mm3 of fuel, values are no more linear for same rail pressure. There is even "inversion", where for 70mm3 of fuel there is greater injection time for fuel pressure of 1400 bar than of 1350 bar. And with all logic, it should be vice versa.
Original duration map looks like this:
Original duration map
In stock ECU software, there is minimum of 300bar pressure and max of 1350bar. Also, there is max 60mm3 of fuel injected...so that strange values are not used. But, when remapping and requesting more fuel, also requesting more rail pressure...this stock values seems not to be good. If I put this at graph, it can be seen that there is break about at 65mm3 where curves for rail pressure rapidly raises:
Original duration graph
It can be seen that line for 1350bar and 1600bar are more or less linear and OK, but others are raising rapidly after 60, 65mm3.
So, when doing linear extrapolation of last two columns (like everybody suggests when increasing axes for maps), map that allows 80mm3 of fuel looks like this:
Duration map with extrapolation
And in graph, it looks like this:
Duration graph with extrapolation
It seems preety messy and wrong to me.
If I do some math and visualisation correction of graph, I end with this kind of map:
Modified duration map
Modified duration graph
And that looks OK to me. So, my question is...why is stock map looks that strange?
If I look to duration maps of other cars...there are allways nice linear curves. But this and other JTD 8V engine...a total mess.
So what would you suggest to go with; linear extrapolated map of last two columns with that strange values or map with modified values to match linearization and have a nice linear curves?