Forced Induction Fueling

[gpr]

I had found some post where people used the commanded fuel map in a COS to run NA fueling until the PE threshold is met, then richen it further with PE as boost increases. I tried doing this but it isn't working. I attached my tune, and a picture of a log showing it is still running over 14:1 afr.

Also note in the picture, that because of the high elevation atmospheric pressure is 12.3. Thus everything above that is boost. Essentially i am running at 14.7:1 afr until it hits my PE threshold of 14psi (2 psi of boost) to turn on PE.

It seems i saw where people would use the B3647 commanded fuel vs RPM map to make it run at richer levels but it seems to be ignoring this table, how come? I turned off my 02's so it is running closed loop now, does this make it ignore B3647?

If you look at the log 12,300 is about where I'm talking about.

[darcy]

I believe you need to max out B4205; as soon as you achieve this temperature, it goes into CL mode and ignores B3647 - Max it out and let B3647 give you SOL where you want it.
Do you have a log from low ECTs (<34deg C) that you can check this out against?

I presume setting the whole B3647 to 1.17 was just in trying to get it to function?

There are a couple of OOR values that are worth fixing too.

Also, why are you talking about 14.7:1 AFRs? Tune appears to be setup for E85 - stoich set at 9.7 and you log confirms this.
Definatly try to talk, and think, in EQRs.

[gpr]

Since I have both stft and ltft disabled then B3647 is ignored? That explains what is going on.

I'd assume it is okay to run at 14.7:1 afr until 2 PSI as it isn't causing any issues or knocking, and I'd think it would help the turbo spool quicker.

I talk in afr but use lamba in the tune. reason being the lc1 in the car only displays afr and is easier for me to relate. I don't see why people insist on using EQR really.

Is it basically just the inverse of lambda? for example if lambda is .8 EQR is 1.2, is this correct? If so why not make it simple with lambda?

[darcy]

Since I have both stft and ltft disabled then B3647 is ignored? That explains what is going on.

No, STFT are NOT disabled in your tune. Only LTFT and STFT-Idle are. Use B4205 to stop STFT ever being enabled - then since this is a COS, SOL will be active from wherever B3647 is set to 1.000



I'd assume it is okay to run at 14.7:1 afr until 2 PSI as it isn't causing any issues or knocking, and I'd think it would help the turbo spool quicker.


I'm not sure about spool, but off-boost performance will be sharper if fuel transitions in from normal NA loads, say 60-70kPa.



I talk in afr but use lamba in the tune. reason being the lc1 in the car only displays afr and is easier for me to relate. I don't see why people insist on using EQR really.

Is it basically just the inverse of lambda? for example if lambda is .8 EQR is 1.2, is this correct? If so why not make it simple with lambda?

Fair enough on the AFR/Lambda, some people can't make the distinction between AFR & (EQR x Stoich) or (Lambda / Stoich) as you are doing. I do the same since my MTX-L is always displaying for Gasoline, irrespective of the fuel.

Yes, EQR is inverse of Lambda. If Lambda works for you, then that's great.
EQR is the natural units of the ECM, and is a simplier calc when dealing with other adders or multiplier are involved.
Bigger number = more fuel is an easy way to think about it too, when first getting away from working in AFRs.

[joecar]

Yes, B3647 is used only in true OL.

For example:
if you're running in CL, and you transition to PE, you are now in a pseudo-CL mode where the trims are being added to fueling (negative trims rounded up to zero) even tho the trims are not being updated... in this mode, the only active fueling table is PE B3618.

In true OL mode, when you transition to PE, there are two active tables: PE B3618 and OLFA B3647 (or B3605 for non-COS)... at the current operating point in each of the active fueling tables, the richest cell is selected as the commanded EQR.