converting VE% to engineering units

[joecar]

It is callled the "VE table", but it really is the "cylinder airmass table".

[Blacky]

As has been said by a number of posters, the "VE table" in the LS1 PCM is not a true VE table. It is a "massometric" table. It defines the predicted mass of air in a cylinder at any given MAP/RPM combination. The table predicts the *real* mass of air in grams so it is easier for the PCM to calculate the correct mass of fuel via the IFR table(s) required to achieve the commanded AFR.

EFILive has just been in CA, working very closely with EFI University to make sure the EFILive Training course that will soon be available is 100% accurate. Ben from EFI University grilled us unmercifully for two days about the "hows" and "whys" of GM's version of the "VE table". Over the course of 2 days, I think I lost 4 out of 4 "wagers" with Ben, he is too clever and has too much experience.

Anyway a number of interesting things were tested that really puts the whole "VE table" in perspective. I won't try and explain what was figured out during our time with Ben, that research was conducted by EFI University and I am not at liberty to post their results on a public forum.

I highly recommend getting along to the EFILive 101 course when it is available. There will be some pretty eye-opening revelations and a sprinkling of "internet mythbusting".

Regards
Paul

[blandmiller]

Blacky, how did you lose a wager to a 'Base Efficiency Numerator'? Just kidding, I couldn't resist.

I guess we will wait for the EFI University course to get an explaination of GM's 'black art' VE tables.

[GMPX]

Blacky, how did you lose a wager to a 'Base Efficiency Numerator'? Just kidding, I couldn't resist.

Blacky said 4.........I was there, I know the real number
Your LL8 is a little better, it was designed to be a stand alone S.D system, not like the LS1, the S.D mode on the LS1 has always been a backup mode for a MAF faliure, we just exploit it!.

Cheers,
Ross

[caver]

I highly recommend getting along to the EFILive 101 course when it is available. There will be some pretty eye-opening revelations and a sprinkling of "internet mythbusting".

That,the advanced course and the certified course are my 1st priorities besides a roof and a job when I get to Ozz

[EFIGUY]

Guys,
Here is a look at the course outline for the EFILive training course.

While a lot of it is a basic look at how to operate the software, some time will also be spent on general tuning theory like: how to choose an A/F ratio, how to properly tune the ignition timing, why road tuning cannot match the performance of dyno tuning, etc.

We will look briefly at how some of the tables work, like the "VE" table, but the course is ABSOLUTELY NOT an engineering look at how the inner workings of a GM PCM work.

This is not an advanced level workshop for guys who have been long-time users of EFILive and are looking for engineering level answers to problems.

If you want to know how and why an engine works, and how to tune it, (using EFILive) then the course is for you.

We plan to release a schedule with various dates around the USA in the next week or so.



I. Introduction to EFILive FlashScan
a) What is it
b) What can it do

II. Installing the software

III. Scan Tool

IV. Connecting to the vehicle

V. Selecting PIDs

VI. Configuring the dashboard, and charts

VII. Creating MAPS for data collection
a) Selecting data
b) Setting up axis’
c) Setting filters

VIII. Collecting the data during operation
a) On the street
b) On the dyno
c) Black-Box logging
1) Set up
2) Collecting
3) Extracting data from Black Box

IX. Bi-Directional Controls
a) Control panel
b) Idle Air Control
c) Cylinder Balance Test
d) CKP Learn
e) Changing VIN’s


X. Tuning Tool

XI. Reading the calibration from the ECU

XII. Saving to a file or folder

XIII. Table definitions
a) Fuel tables
1) Main VE Table
2) PE Modifiers / EQ Ratios
3) Closed Loop
b) Ignition Tables
1) High Octane
2) Low Octane
3) Using Spark to Control Idle
c) Idle control Tables
d) MAF Tables
e) Rev Limiters

XIV. Making Changes to Calibrations
a) Entering changes manually
b) Using the %, +/-, and # tools
c) Smoothing cells
d) Filling cells with linear data
e) Moving forwards and backwards in calibrations
f) Saving current file
g) Saving new file
h) Sending to the PCM

XV. Using data from the Scan Tool
a) Copy special
b) Paste special
c) BEN Factor

XVI. Miscellaneous Functions
a) Speedometer Calibration
b) Tire size calculator
c) Configuring display units
d) File compare functions
e) Modification summary
f) Table Search function


XVII. Installing a Custom Operating system
a) Which version is right for you?
b) Step by Step
c) Things to watch our

XVIII. Understanding Fuel and ignition requirements
a) Selecting the proper A/F ratios
1) Idle
2) Cruise
3) Power
b) Getting the correct timing
1) Knock Retard Count
2) Knock retard Amount
3) Proper Dyno Calibration

XIX. Proper Dyno Tuning Procedures
a) Strapping
b) Driving safety
1) Vehicle control
2) Using the Brakes
3) Using the clutch to prevent over-running the engine
4) Circle of Awareness
c) Thought process for tuning from beginning to end


-Ben

[MICK]

yes, that's why i'm so anal about keeping things as constant as possible. i've seen changes based on fuel temperature, cooling capacity, variances in battery voltage, and other things that noone usually monitors, yet introducing 'noise' that we cannot account for emprically. having solid hardware really cleans up your signal and limits variation in your data, yielding better, more consistant results quicker.

if you wanna see the formula involved in getting the VE numbers read the 've table cracked' sticky in the pcm section on ls1tech.
i've been thinking of building a probabilistic model just to see where the biggest variances are, so we could locate the biggest sources of noise.

Funny you should say noise. I found some converting back to VE when referencing the same preset figure at a different map table location. Was very noticeable in the area just off idle, very interesting?

Thanks mick

[redhardsupra]

sure, just off idle is usually transitory, how many times do you actually cruise at 6mph? however the values corresponding to cruising at 35, 55, 75mph (usual speeds in city/hiway) are usually pretty dead on. i bet you they're directly proportional to the number of samples gathered.

[MICK]

sure, just off idle is usually transitory, how many times do you actually cruise at 6mph? however the values corresponding to cruising at 35, 55, 75mph (usual speeds in city/hiway) are usually pretty dead on. i bet you they're directly proportional to the number of samples gathered.

No Not Really. I am not gathering my info from Scaned Data. I am using two different softwares to look at the VE table of the same tune cal in bin format. (Cats OBD2 Engineering Units and EFI live VE). Then I compair a preset figure at different map table location and this is where I am finding differences in the VE % table compaired to the Engineering Units. It almost looks like temp and pe might have a play in the VE table where Engineering units table is raw code data converted without any extras. Not sure?

cheers

mick