Calc.BEN_lc1 (AutoVE tuning)

[FeetDry]

I'm trying to apply the AutoVE tuning tutorial to the 2000 Vortec.

There is no CALC.BEN_XXXn pid. What is the calculation for the Base Eff Numerator?
What is BEN, other than just a number? I have yet to find an explanation for it, but it is mentioned everywhere on the forum.

Base Eff Numerator does not apear in the Param drop down box, of the MAP property editor box. How do I fix this?

Thanks

[Taz]

Hello FeetDry,

With regard to VE (Volumetric Efficiency), utilizing BEN (Base Efficiency Numerator) function is a means of adjusting or scaling your existing VE table to be representative of your engine’s current (new) VE.

As an example - installing a longer duration camshaft generally increases power output in the upper RPM range, often accompanied by a reduction in power output in the lower RPM range. This is directly related to increased VE in the upper RPM range, and decreased VE in the lower RPM range.

In the above example the BEN factor in the lower RPM range would be less than one, and in the upper RPM range it would be greater than one. Applying this BEN function to the original VE table would have the effect of multiplying the lower end of the VE table by a number less than one (reducing the VE value), and the upper end of the table by a number greater than one (increasing the VE value).

If your engine had a “perfect” tune – the result of the AutoVE exercise would yield a BEN factor of one for all cells in the VE table.

In the AutoVE Tutorial the “CALC.BEN_XXXn” PID is intended to be a generic descriptor.

XXX = your particular wideband oxygen sensor (WBO)
n = 1 or 2 (input A1 (PID – EXT.AD1) or A2 (PID – EXT.AD2) on your V2)

It looks like you have a LC-1 WBO. The applicable PIDs are:

To use input A1

CALC.AFR_LC11
CALC.BEN_LC11

To use input A2

CALC.AFR_LC12


CALC.BEN_LC12


Good luck with the AutoVE …..


Regards,
Taz

[joecar]

CALC.BEN_LC11 is defined as {CALC.AFR_LC11.AFR}/{GM.AFR} --> it is the ratio of measured AFR to commanded AFR --> this is the correction multiplier needed to correct the VE or MAF table (as Taz said above)... you have to set up the tune to run from VE only or from MAF only, respectively...

the idea is this: you set up the tune to run from VE only... then any difference in wideband AFR compared to commanded AFR must be due to the VE providing the incorrect airmass;

same if you run from MAF only, any difference in wideband AFR compared to commanded AFR must be due to MAF providing the incorrect airmass;

the BEN pid compares the wideband AFR against the commanded AFR --> the BEN is the correction multiplier that you multiply the VE table or MAF table to correct it.

The AutoVE tutorial sets up your tune to run from VE only.


If it's not in the map pid dropdown, then goto the PIDs tab and make sure you have selected the calc pid, and save the log file (it will add the calc pid to the file).


Do you have FlashScan V2...? --> If so, then you should be using serial AFR {EXT.WBO2AFR1} and serial BEN {CALC.BEN1}.

[FeetDry]

Thanks for the info.
As I see it, the AutoVE approach uses the MAP (only) to supply the fuel amount.
The Weatherman's approach uses the MAF (only) to supply the fuel amount.
Does this sound right?
I have found neither approach to work for the Vortec. OR at least how they are written up.

I'm using a V2 with a single LC-1. (2000 L31 4.3L V6 Vortec) The WB is setup for serial comm. (No A/D stuff.) I'm trying to do this in "blackbox" mode. (Just a V2) I'm using the latest V8 package, to setup the blkbox settings.

GM.EQIVRATIO is not supported in the L31, according to V7.5. I can't tell if it is a DMA value or not. (There is no "more info" for that PID.) Does GM.EQIVRATIO = AFR_B?
These are some of my PIDs: WO2AFR1, WO2LAM1, WO2EQR1, WO2LAM1, and AFR_B
With these, the BEN I'm looking for should be: BEN= WO2AFR1/AFR_B = Measured/Commanded
Is there something wrong w/ this approach?

I'm not sure what the equation is for AFR, as a function of Lamda. Is it possible to use Lamda to calc BEN, rather than useing the resulting AFR #?

I'll guess I can't see any "calc" PIDs in the V8 list because I'm doing BlkBox. I'm guessing the EFILive app does the calc part, not by the V2, thus no CALC PIDs. So I need to do a scan, upload the data to V7.5, then calc the BEN numbers for the table. Does this sound right?

[Taz]

I misread your original post ... you have a '00 L35 4.3L with black box Vortec PCM ... was thinking '01 model with LS1-B PCM. Give this thread a read ... same sort of issues you are facing .... person was eventually able to perform an SD tune (Mafless AutoVe) on a V6 S10.

http://forum.efilive.com/showthread.php?t=9208&highlight=olsd


Regards,
Taz

[joecar]

EQIVRATIO is either stoich/AFR or stoich/AFR_B where stoich is your stoich AFR... if you have EQIVRATIO, then use it rather than AFR or AFR_B.

AutoVE tutorial corrects the VE derived airmass calculation by applying BEN correction to the VE table.

Weatherman's tutorial does two things:
- corrects VE derived airmass calculation by calculating the VE table (from scratch) and then applying LTFTBEN correction to it,
- corrects MAF derived airmass calculation by applying LTFTBEN correction to the MAF table;

i.e. not the fuelmass itself (the fuelmass is corrected by virtue of the airmass being corrected).

Both approaches do use MAP to calculate the airmass... VE uses only MAP, Weatherman's uses both MAP and MAF.

You should be able to get AutoVE to work if you can isolate the airmass calculation to the VE table only;
You should be able to get AutoMAF to work if you can isolate the airmass calculation to the MAF table only;

You should be able to get Weatherman's to work if you can get all the parameters required to calculate VE (MAF, MAP, RPM, DAT) [DAT can be calculated in various ways] and LTFT's (for correcting both the calculated VE table and the MAF table).


The two relationships you need are: Lambda = AFR/stoich and EQR = 1/Lambda

Yes, you can use Lambda to calculate BEN... i.e. BEN = {GM.EQIVRATIO} * {EXT.WO2LAM1}

It is preferable to use wideband Lambda rather than wideband AFR since AFR depends on the stoich AFR.


Yes, correct, calc pids are not included in V8 while logging... they are added in later when you view a log using V7.5 scantool.