Hi

I had been interested to find out has factory optimized maps for NOX limits or best Mileage.
So i arrange some tests. First i was defined my test environment. I was make quick physical limiter to driver wish potentiometer. This way i was easily to get exact same driver wish all test round. Then i was looking good test road. Little up hill condition.
I was first logging with original SOI maps and got exact same results. Then i was adding 2 degree more timing for seeing is my results going up or down but i disappoint was huge when i noticed that lexia was reporting exact same timing values than before re-mapping.
Then i was found other map, what i was thinking that it is kind of limiter for SOI. I was up-grading it also, but no any change during testing.

So testing is made by:
- driver wish 18.4%
- IQ approx 20
- engine speed 1600-1960rpm
Lexia is reporting follow values:
rpm1600=2 degree
rpm1800=2,5 degree
rpm2000=3,7 degree

Now kindly asking you guys to check my files for seeing what i had missed or doing wrong.

You see that My changes for SOI is done on addresses:
SOI:6AFDE
SOI limitter?: 68A2A

Starting study more and found out that there is REAL SOI1 in address 6283A(2d inverse)
From there i can found values what is logged by lexia.

First comparisons done and there is good and bad news.
Turning 1 degree more advanced, was lowering performance(1500-2000rpm@IQ20)
Turning 1 degree to retarded, was lowering little bit performance
Going back to original was giving that same best performance what i measured in first place.
(2degree@1500, 2,5@1700, 3,1@1900, 3,7@2000rpm)

So good thing is that factory has made good job for optimizing SOI for best BSFC. Before testing i was expecting that factory has made compromise for NOX, but that wasn't case this time.

So it seems that i can't get any gain for Mileage adjusting SOI. What i can try next ?

Good SOI map will affect mileage. Rail pressure will also affect mileage. The best thing to do is to make good combination of SOI and rail pressure.

So next step is testing is rail pressure optimum. If i got better rail pressure values, then check again is can i get even better measurement by chancing SOI values.
Maybe first trying to rise up RAIL pressure.....

I was continuing testing today. Agenda for testing was RAIL pressure.
First i was got slightly "JIHAA" when i got better results with 10% higher rail pressures but during back up testing with old rail pressure map i noticed that WARM engine was doing that difference. So next time need to take care that measuring is done after good warm up.

Now i need some help, because i really i can't find correct axis info for rail pressure map or SOI map.
I found other post from forum and i got some feeling that maybe i got RPM info at 0x6102C(or 0x610E4) and IQ at 0x61086(or 0x610BE)
Only issue what bothers me is that assumed IQ axis is ending to 55 and measured values is not matching perfectly to values on MAP.
So question is: Did i found correct axis and there is something else what makes difference between logged and theory values ?
Or are these two maps working with out axis values ??

RPM freak wrote:Good SOI map will affect mileage. Rail pressure will also affect mileage. The best thing to do is to make good combination of SOI and rail pressure.

And took about one year for understand that i must look EOI value, and that basically means adjusting SOI and Rail pressure.
I found out that EOI values is kind of retarded on area IQ16-30/RPM 1500-1750
So adjusted some slightly SOI and rised up that one hole from RAIL PRESSURE map.
After all calculated EOI values was changed about 0,2-0,66degree

What were the results - did you get better mileage / performance from this change?

Nope. I was doing 3 test round with original and 3 with changes. And one with AC on with original.
When i was compared results really carefully, it was look that original was little bit better or equal. BUT results with AC on was terrible :) So at least my test condition was perfect and able to rise up differences.
So end result still is that for steady driving with IQ 20, factory maps has been best one.

Interesting. Should put the bed the myth that ECU's are detuned for NoX and emissions and you can get better mileage by tweaking SOI and rail pressure, on the HDi engine at least.