Fuel Scalar and it's limits (Ethanol)?

135boost

Corporal
Oct 28, 2017
245
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Finland
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135is
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
 

TiAgAu

Corporal
Nov 18, 2018
139
56
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Australia
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08 335i
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
 
Last edited:

carabuser

Lieutenant
Oct 2, 2019
882
1
780
0
UK
Ride
Z4 35i & 335i
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).

1636293657151.png


@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
 
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RSL

Lieutenant
Aug 11, 2017
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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

Sergeant
Nov 26, 2019
284
147
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E90 335i
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

Lieutenant
Oct 2, 2019
882
1
780
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UK
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Z4 35i & 335i
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.
 
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KClemente

Sergeant
Nov 26, 2019
284
147
0
Ride
E90 335i
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

FirmwareInterfaceEngineTMAP_VAvgIgnDWPMethTriggerModeFFMethSafeModeMethAddMethScaleMethPSIE85_SetupVFF_Offsetfuel_30fuel_35fuel_40fuel_45fuel_50fuel_55fuel_60fuel_65fuel_70
32/16//2JB4 iOS 9432E Series - N541.93.5600650000.08132000000000

BoostSafetyPID GainAutoShiftRedFuel_OLFUA1st_limiter2nd_limiter3rd_limiterOptionsN20_TMAP6CylModeLastSafetyduty_15duty_20duty_25duty_30duty_35duty_40duty_45duty_50duty_55duty_60duty_65duty_70
28.03000016.00.00.0108140505050505054586064666870
 

carabuser

Lieutenant
Oct 2, 2019
882
1
780
0
UK
Ride
Z4 35i & 335i
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.