Does B0141 actually do anything (stock values set to 0.1...?)

[MadMaxHSV]

My stock tune and corvette E40 tunes i've seen have this table (and the other commanded open loop tables) set to 0.1 (lambda). Which surely can't be right and therefore not being used....

E38 tune i've seen actually have meaningful values in here.

Am I missing something. None of the other multipliers increase this either.

[MadMaxHSV]

Ok, reading some related threads I figure it does nothing as Open loop with this OS only happend when PE is triggered.
Then I assume the PE commanded fuel is used.

Does this sound right? Maybe another OS goes open loop in places other than PE...

[swingtan]

In my E38 tune, it certainly makes a difference as long as you are in OL mode ( which is all the time for me ATM ).

However, if you are using the O2's to trim (CL Mode), once entering CL Mode it does nothing (remember that all tunes run OL for a short time just after start up, utill the NB O2's warm up). That is because PE mode is not OL mode, when it comes to this table. PE mode is more like "rich CL mode" and the PE mode fuel tables are used. They are all directly referenced back the set stoichiometric level in B3671.

I've had a look at an HSV tune and that had values of 1.46 in B0141, which when multiplied by the values in B0146, comes out to about stoich. The funny thing there is that it's b0146 that has values of 0.1, not B0141.

Simon

[Tordne]

Hey Simon. You running MAF or SD these days?

[MadMaxHSV]

In my E38 tune, it certainly makes a difference as long as you are in OL mode ( which is all the time for me ATM ).

However, if you are using the O2's to trim (CL Mode), once entering CL Mode it does nothing (remember that all tunes run OL for a short time just after start up, utill the NB O2's warm up). That is because PE mode is not OL mode, when it comes to this table. PE mode is more like "rich CL mode" and the PE mode fuel tables are used. They are all directly referenced back the set stoichiometric level in B3671.

I've had a look at an HSV tune and that had values of 1.46 in B0141, which when multiplied by the values in B0146, comes out to about stoich. The funny thing there is that it's b0146 that has values of 0.1, not B0141.

Simon

Yes sorry, was forgetting about the other OL scenarios. Not sure how I forgot since i've done plenty of SD OL tuning *doh

Still then confused how the hell it gets to a relevant figure from 0.1 in this table (its 1.46 if set to commanded fuel display is set to AFR, 0.1 must relate to 1 lambda eventually, but how)

The formula in the notes states

B0141 + (B0142 - B0141 x B0145) x B0146 x B0148 = Final Commanded

My values in B0146 are "0.1" most of the time and B0148 is all "1".

So to follow this logic

0.1 + (0.1 - 0.1 x 0) x 0.1 x 1 = 0.01

Unless there is a divisor there somewhere this doesn't add up.

[MadMaxHSV]

Ok think i've sussed it.
Confusion relates to the units used and the note help.

If I set properties to show commanded in EQ Ratio then the formula makes sense. Although the value in B0141 does not relate directly to commanded (as the table name would suggest)

Set to EQ ratio, B0141 = 10. B0146 and B0148 are in units of 'factor' so don't change.

Therefore as per the equation:

Commanded = 10 + (10 - 10 x 0) x 0.1 x 1 = 1

So basically Stoic.

So regardless of unit the related EQ Ratio to the value in B0141 must be used during the calculation.

It's late and my brain hurts.
Shame there isn't a commanded table relating to RPM vs MAP or the like.

[swingtan]

Hey Simon. You running MAF or SD these days?

Running MAF. I still feel that with SD, the dynamics are simply not able to be tuned as finely. Probably fine for an auto or if you don't care too much about part throttle, but I'm aiming to get it perfect for all conditions. Maybe I'm making a huge rod for my own back doing this but at least it keeps me busy.

Re the fueling, I think you've got it sussed MadMax. When you take into account the actual units for each table, it all makes sense. B0141 is the "base" fueling table (for a manual anyway). The other tables adjust the base fueling based on running conditions. If you never intend to run a "flex-fuel" tune, then I'd keep B0141 to B0144 all the same. This just helps make sure nothing funny happens. Then just use B0146 to B0148 to fine tune for changing engine conditions.

Simon