Fuel Scalar and it's limits (Ethanol)?

[135boost]

Hello, long time since last post.

On my build of n54 and hounting noprep 9 sec 1/4 i buid total new engine to my 4wd E82.

i have a issue with fuel scalars maxxed out to 1.60 and as chris said, there is no hard limit 1.60, but 2.01
and that is enough headroom to play with at this moment


mods what caused this was big valve 235cfm@12mm 175cfm@12mm (stock 159cfm intake) cylinder head with
big lift cams.

i have search for ijeos xdf where there is that scalar main table to play with.

please, if someone can help me out with this issue because now on 1.60 it run extremely lean.


br.

Jan

 

[Neophyte]

It's pretty simple to change by right clicking the fuel scalar then choose edit parameter xdf info and change the high range to 2.0000

Or don't worry about it, and just use the ijeos xdf from here scalars can be set to 2.00 max now

 

[135boost]

forgot to thank about help

 

[carabuser]

Just a thought for people running Ethanol. There's a table in the DME that's used as a constant in the fuel mass calcs that might be useful.
The stock cal has the DME set for 1/14.15 for stoich which makes sense as the fuel cap states something about E10 being OK.

This is the address for INA0S:
I have the conversion set as: 1/(X*0.000001907225146868086).

@135boost Maybe this would help you avoid having to use scalars to correct and potentially keep the DME happy at higher blends. This value should in theory compensate but I haven't tested since I don't get E85 here. The IJE0S address is 0x4BD8E

 

[RSL]

There's an MAF mff monitor that probably ties in somewhere. I recognized the 14.15 AFR from one I defined, INA0S is 4BF0A. It's also stoich constant for lambda.

 

[KClemente]

Just a thought for people running Ethanol. There's a table in the DME that's used as a constant in the fuel mass calcs that might be useful.
The stock cal has the DME set for 1/14.15 for stoich which makes sense as the fuel cap states something about E10 being OK.

This is the address for INA0S:
I have the conversion set as: 1/(X*0.000001907225146868086).

View attachment 61890

@135boost Maybe this would help you avoid having to use scalars to correct and potentially keep the DME happy at higher blends. This value should in theory compensate but I haven't tested since I don't get E85 here. The IJE0S address is 0x4BD8E

I'll try it out with E70-E85 next time I fuel up. I8A0S is 0x421F4.

In theory, all I would have to do is input 9.77 and now the DME will automatically change its calculation in injection quantity.

 

[carabuser]

I'll try it out with E70-E85 next time I fuel up. I8A0S is 0x421F4.

In theory, all I would have to do is input 9.77 and now the DME will automatically change its calculation in injection quantity.

That's the theory. It's used as a factor of the fuel mass target so that should request a load more fuel from the injectors.

Keep an eye on afr for the first run with the MHD gauges. I'd also reset trims.

 

[General.Massacre]

Innovation to the max always like seeing new info i didnt know. good going

 

[KClemente]

Tried it out with E70-E85 (my ethanol tester is broken but this station is known for that variance) and as you can see in the datalog, it starts off high and then reaches a bit of an equilibrium. As soon as I start driving, trims immediately go crazy and will easy hit 50 aka 34% stft.

Fuel trims were set to 1.0 across the board.

Additional information

Firmware	Interface	Engine	TMAP_V	AvgIgn	DWP	MethTriggerMode	FF	MethSafeMode	MethAdd	MethScale	MethPSI	E85_Setup	VFF_Offset	fuel_30	fuel_35	fuel_40	fuel_45	fuel_50	fuel_55	fuel_60	fuel_65	fuel_70
32/16//2	JB4 iOS 9432	E Series - N54	1.9	3.5	60	0	65	0	0	0	0.0	8	132	0	0	0	0	0	0	0	0	0

BoostSafety	PID Gain	AutoShiftRed	Fuel_OL	FUA	1st_limiter	2nd_limiter	3rd_limiter	Options	N20_TMAP	6CylMode	LastSafety	duty_15	duty_20	duty_25	duty_30	duty_35	duty_40	duty_45	duty_50	duty_55	duty_60	duty_65	duty_70
28.0	30	0	0	0	16.0	0.0	0.0	108	1	4	0	50	50	50	50	50	54	58	60	64	66	68	70

Hide legend Reset zoom

 

[carabuser]

Tried it out with E70-E85 (my ethanol tester is broken but this station is known for that variance) and as you can see in the datalog, it starts off high and then reaches a bit of an equilibrium. As soon as I start driving, trims immediately go crazy and will easy hit 50 aka 34% stft.

Fuel trims were set to 1.0 across the board.

Additional information

Firmware	Interface	Engine	TMAP_V	AvgIgn	DWP	MethTriggerMode	FF	MethSafeMode	MethAdd	MethScale	MethPSI	E85_Setup	VFF_Offset	fuel_30	fuel_35	fuel_40	fuel_45	fuel_50	fuel_55	fuel_60	fuel_65	fuel_70
32/16//2	JB4 iOS 9432	E Series - N54	1.9	3.5	60	0	65	0	0	0	0.0	8	132	0	0	0	0	0	0	0	0	0

BoostSafety	PID Gain	AutoShiftRed	Fuel_OL	FUA	1st_limiter	2nd_limiter	3rd_limiter	Options	N20_TMAP	6CylMode	LastSafety	duty_15	duty_20	duty_25	duty_30	duty_35	duty_40	duty_45	duty_50	duty_55	duty_60	duty_65	duty_70
28.0	30	0	0	0	16.0	0.0	0.0	108	1	4	0	50	50	50	50	50	54	58	60	64	66	68	70

Hide legend Reset zoom

There also another factor that's applied to the fuel mass target when converting from % to mg/hub.

Conversion factor: X/754.9143268538517

This will certainly alter the fuel mass request, this factor is applied to each fuel injection phase (1,2,3) and the purpose looks to be converting the fuel mass into an actual mass value.

 

[KClemente]

What're some numbers you're thinking I should try?

 

[carabuser]

Increasing it should increase the fuel mass target. I would start by keeping everything else in your tune as it was with your original scalars then increase this value by 5% and see if trims fall slightly.
This should be a way to globally correct for fuel mass changes. I also notices there's an enrichment table for cold starts, has the cold start enrichment stuff already been defined for E85 users?

 

[KClemente]

Yup, we used the Fuel (Start) and Warmup enrichment tables with fairly specific but linear values depending on temperature

 

[KClemente]

Took me a few extra minutes to find it than normal, but it's because it seems that I8A0S has a totally different hex. C2 B6 instead of BC 86

 

[135boost]

To cheat more fuel to engine, and to "downscale " scalars, one possible way could be cold start enrichement factor.

just leave warm engine factor to some 1.05-1.10 or so should add more fuel trough whole table.

i maxxed out those tables to value 2.0 trough quite big area because of maxxing out the engine to level what it was not intended to do.

30psi boost fully built engine with high lifts and head 8000 rpm powerband and almost only di with db shotgun.
it keep hfpf at 3500psi to at least 7000 so hfpf fuel delivery is enough, scalars maxx out at 2 points of map, first
at 1800-3000 with 80-130 load, then i think it jump to single injection mode from that 3000 because of drop to 1.70 scalars and then again start to reach that 2.0 level in +200 load and 5000rpm

i have mystery misfire there what i have discussed in another topic but what i try tofigure out too is to get those
scalars down to archieve some headroom and to get enough boost with reduced load values, maybe 4.0 tmap or something...

 

[carabuser]

To cheat more fuel to engine, and to "downscale " scalars, one possible way could be cold start enrichement factor.

just leave warm engine factor to some 1.05-1.10 or so should add more fuel trough whole table.

i maxxed out those tables to value 2.0 trough quite big area because of maxxing out the engine to level what it was not intended to do.

30psi boost fully built engine with high lifts and head 8000 rpm powerband and almost only di with db shotgun.
it keep hfpf at 3500psi to at least 7000 so hfpf fuel delivery is enough, scalars maxx out at 2 points of map, first
at 1800-3000 with 80-130 load, then i think it jump to single injection mode from that 3000 because of drop to 1.70 scalars and then again start to reach that 2.0 level in +200 load and 5000rpm

i have mystery misfire there what i have discussed in another topic but what i try tofigure out too is to get those
scalars down to archieve some headroom and to get enough boost with reduced load values, maybe 4.0 tmap or something...

The reason you have to have those scalars so high is due to you under-reporting load.
Fuel mass target is calculated from actual load, if you are at 30PSI and only reporting 180 load then that's a problem.

 

[135boost]

On these logs, it report 210+ load at 28.5 psi

 

[carabuser]

On these logs, it report 210+ load at 28.5 psi

That's quite a lot lower than it should be. I think 210 would be around 22PSI. That combined with Ethanol is why you have to have scalars so high.

 

[P33P33]

That's quite a lot lower than it should be. I think 210 would be around 22PSI. That combined with Ethanol is why you have to have scalars so high.

The tune is using the MHD logic change for higher boost (3 cell tmap conversion) so those values are in line what I have seen with that.

 

[wheela]

The tune is using the MHD logic change for higher boost (3 cell tmap conversion) so those values are in line what I have seen with that.

I'm ignorant on the details of the MHD logic change, but wouldn't scaling load down on the second half of the 3 cell scaling also scale down the calculated charge air mass entering the cylinder to be lower than actual, creating the issue car abuser mentioned? Not challenging, just questioning since I don't know, and would genuinely like to know.