VE table calibration

[bobby singh]

I'm finally working on this again and got the tune approx correct but I'm not happy with the measured lam Vs requested.
In the excel attached you will find logs taken and the VE table.

In column AC you see the % delta between measured and requested lambda.

Are you guys using a formula to correct this in the VE table? doing it ghetto style and experimenting doesn't seem very accurate.

Thanks in advance
Bobby

[prj]

The formulas are known and posted on the wiki and also here in the forum.
There is nothing to guess here, you can do multiplicative or additive correction.

Algo is here:

http://m232.org/index.php/Speed_Density

So just keep it in mind and do the correction so the final value changes as desired.

It is done this way because the ECU is 8 bit, so using the addend and mult it's possible to maximize the resolution of the table by adjusting it so that the table only covers the range that needs to be adjusted.

[bobby singh]

The formulas are known and posted on the wiki and also here in the forum.
There is nothing to guess here, you can do multiplicative or additive correction.

Algo is here:

http://m232.org/index.php/Speed_Density

So just keep it in mind and do the correction so the final value changes as desired.

It is done this way because the ECU is 8 bit, so using the addend and mult it's possible to maximize the resolution of the table by adjusting it so that the table only covers the range that needs to be adjusted.

Hi thanks for replying - I think maybe my question wasn't clear.
What I meant indirectly was if I have say 4% delta between requested and actual lam could I take out the same % from the VE map?
Or is there a formula one could use.

Thanks

PS If I was willing to pay for your time could you add another 0 to 5v input? I want to log EGT eventually - have a efr 83 to go on.

[prj]

Hi thanks for replying - I think maybe my question wasn't clear.
What I meant indirectly was if I have say 4% delta between requested and actual lam could I take out the same % from the VE map?
Or is there a formula one could use.

Thanks

Your question was perfectly clear and so was my answer. You have to be able to do primary school math.
No, modifying the map by 4% will not modify the end result by 4%.
X = (A+B)*C = A*C + B*C
If you multiply A by 1.04, then only the first part changes by 4%, but not the second.

PS If I was willing to pay for your time could you add another 0 to 5v input? I want to log EGT eventually - have a efr 83 to go on.

lol no. I am not for hire.