1227747 $42 VE1 + VE2 Fuel Tables

[dave w]

The screen shots below show how to add the '7747 VE1 + VE2 tables.

It's my understanding that once the '7747 ECM goes above 3200 RPM's, the ECM will use the last known VE value from the 3200 RPM table. Typically, the 3200 RPM VE values are at or above 90's ( VE1 + VE2). It's very likely an engine operated by a '7747 at or above 3200 RPM's will already be above 80 Kpa.

With the correct BPW the ideal VE1 + VE2 table will have low numbers in the low 40's and the high numbers will be no higher than the mid 90's.

Use at your own risk.

dave w

[CDeeZ]

Thanks for posting this dave.

This makes a lot more sense than jockeying two separate tables.

After adding them, do you slew the table down at all before logging BLMs, so the VEs are not over 100??

[dave w]

I only adjust VE1, even on a stock .bin file that will be using both VE1 and VE2.

For VE cells over 100, I adjust to 96 and increase the BPW slightly ( usually 3 or less).

I'll add VE1 + VE2 for modified engines (cams, heads, pistons, intakes, ect). For a stock or nearly stock engine, adjustments to BPW and VE1 are all that is usually required.

dave w

[EagleMark]

Thanks for posting this dave.

This makes a lot more sense than jockeying two separate tables.

After adding them, do you slew the table down at all before logging BLMs, so the VEs are not over 100??You have no choice in TunerPro, it will do it for you.

I've read some other srticles on this and says to leave VE2 adder alone after 3200. This does not work. I've verified Daves way with a Wide Band O2 sensor and it works fine.

[EagleMark]

Dave I found a better way to add to BPW/BPC in these, add to injector bias.

[CDeeZ]

You have no choice in TunerPro, it will do it for you.

I know that TPRT caps the VE values at 100 or 99.6 or whatever it is.




I must say, configuring the VE tables using daves method of VE1+VE2 has given me better results than anything else I've tried as far as messing with the fuel tables in the 747.

I added my VE tables together using daves method, then slewed the whole table down a few points so that no VEs were over 100, or close to for that matter. I've done several logs and adjusted the fuel table down and now, my highest is like 88 and lowest is like 22. This is after a few BLM adjustments using daves VE calc spreadsheet

Mark I think you told me lower is better regarding VEs, correct? (within reason of course)

I haven't checked BLM since doing the last adjustment but I expect them to be +/-3 in most areas..

dave, you said ideally the lowest VE should be low 40s and highest mid 90s. Really anywhere is OK though as long as you're not maxed out to either extreme 0 or 100 right? I used yet another handy tool of yours, the BPW spreadsheet you created, and came up with my BPW, dropped it into the tune, combined VEs, slewed main VE down a bit and proceeded to collect BLMs. After a few BLM logging sessions my lowest VE is now ~22 and highest VE ~88.

[EagleMark]

Mark I think you told me lower is better regarding VEs, correct? (within reason of course)

No that was not me nor is it correct, VE Volumetric Efficiency has to be correct weather low or high. Just can not exceed 95 in highest cell and lower is better.




I haven't checked BLM since doing the last adjustment but I expect them to be +/-3 in most areas..
Can't get much better then that, even if you did it would change with weather.

The reason Dave W BLM Spreadsheet works so well with this method is it's adjusting 100% of the value, what it is designed to do. If you still had VE2 then... lets say VE2 had 39% rounded to 40% for simplicity. Then you applied the spreadsheet calculations to VE1 which is the other 60%, so you have adjusted 60% of total VE not 100%.

[EagleMark]

Since Dave brought this up and seems to be of intrest I'll give some calibration theory taking from some of the best calibrators/tuners.

First adding VE2 to VE1 fueling table is usually easy and only one number, (Refer to Dave W first post) for instance ADSU is 39.06 for the entire VE1 table, use the Offset +/- tool in TunerPro and add it in, zero out VE2 and save bin with new name protecting your starting bin. This is what you end up with.

Stock with VE1 and VE2 added together.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=2740&stc=1&d=1342184805

1227747 $42 does not have a big resolution of table compared to later masks with say double the amount of cells. Tuning basics says to start with a smooth table, open your wireframe veiw and do some manual smoothing to make the table look more consise, then use the smooth tool to finish it off one cell at a time or row by row, setting it to .10 is a huge smooth and .90 is a small adjustment, I use .5 so it ends up something like this below.

So where do you start? Well if you look at the table, not wire frame, basically leave all four corners alone. Max number in bottom right should be no higher then 95 max, lower is better if you have big enough injectors and fuel pressure to support engine HP.

After smooth.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=2741&stc=1&d=1342184805

Reason for this is the way the ECM/PCM get's it's VE number for a given cell, say your using data tracing or the engien is running in this cell.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=2743&stc=1&d=1342184805

Well the ECM/PCM does not use that cell alone! It is a calculation of that cell plus four surrounding cells.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=2744&stc=1&d=1342184805

With that you can understand how and why it's easier and more accurate let alone easier for the ECM, in this case a slow ECM to make adjustments to fuel as needed.

In the end of tuning and making adjustments via BLM readings and a spreadsheet the final tune would look something like this.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=2742&stc=1&d=1342184805

[dave w]

Mark,
Excellent post!

dave w

[CDeeZ]

Add all your VE2 numbers to VE1 and tune off one table and keep VE below 95, lower is better.

Not trying to argue Mark, just trying to understand.

Wouldn't you want to smooth the final table over a little bit after making BLM adjustments, since the ECM uses surrounding cells in making VE calculations

[dave w]

Wouldn't you want to smooth the final table over a little bit after making BLM adjustments, since the ECM uses surrounding cells in making VE calculations

VE Tuning has some very individual opinions, like some add VE1 + VE2 some don't. Some will smooth, while again others don't. Every engine is different, some work fine with smoothing, while other engine work best with spikes, valleys, and peaks in the VE Table. The data is the data, which is the final judge if adding VE1 + VE2 or smoothing is working for the engine being tuned. I use Excel to tune with, other have excellent results tuning without Excel.

dave w

[RobertISaar]

i allow non-smoothness..... within reason anyways. if a mountain comes up, to me that's a clue that something is seriously wrong.

[EagleMark]

Not trying to argue Mark, just trying to understand.

Wouldn't you want to smooth the final table over a little bit after making BLM adjustments, since the ECM uses surrounding cells in making VE calculationsIn theory you could smooth the last table in the above post, record data and adjust, smooth, data, adjust, rinse and repeat... but the last table shown is well within boundaries of a good tune for that engine.

Reading several tuning books including all of Greg Banish books, when a tune comes together and data or wide band is inline all engines will show a torque hump. I actually found this before studying and tried to tune it out for a final tune without success, then noticed a pattern as I tuned more vehicles. This may not be the case in a race engine that has nothing but WOT high RPM HP. Hard to see it in the low resolution 7747 table/wire frame view but if you look you will see a hump where max engine torque is developing low RPM mid MAP, this is a demand for more fuel. As engine RPM increase demand goes down in wire frame graph and become smoother, but numbers are actually higher due to graph.

See the torque hump at 65 to 75 MAP, 1200 to 2000 RPM? This is typical of a close to stock TBI engine. Something like an LT1 would be bigger and higher do to engine demands and also look bigger do to table resolution having twice as many cells... more IIRC...

You also have to realize there are many cells in the picture or wireframe graph or your VE table that the engine will never hit! Take for instance 400 RPM 100 MAP and that area. Or 3200 RPM 20 MAP? Look at your BLM logs! Can you fill in all cells?

[CDeeZ]

Great information here gentlemen. This kind of stuff gets me thinking, which is why I joined this site :)

You know, I was thinking that it would be best to adjust all (or at least most) cells in the VE table, even though some you can't collect data on like Marks' example of 400 RPM and 100 MAP; or 3200RPM and 20MAP. I was thinking it would be best to adjust all cells whether you got data in those cells or not, that way you could avoid spikes and dips in the VE table, but now ya'll got me thinking that maybe this is just not necessary or ideal to do the VEs that way. I guess really the data is the final judge, as dave stated.

[dave w]

The screen shots below is a stock '7747 VE table BCC AMUR and a stock '427 VE Table BCC BNKM. The factory VE Table will have some peaks and valleys, usually not smoothed out.

dave w

[EagleMark]

That AMUR does not look bad at all? That 427 table is just so wrong... I've seen some huge issues with GM tunes, I think it was 1project2many who described the procedure. First engine dyno produces MBT, that's where it should have stopped! But then had to pass emmissions, then drivabilty, then emmissisions? Either way I don't think their software was as good as we have today so they just grabbed an area and fixed it! Hence the huge spikes and peaks. It passed so they were done, never really a fine tune. Just a theory... But looking at newer stuff is much more fine tuned. So were they trying harder or did software and technoligy make it easier? Remember the dates, computers and software of the era of ECMs we are talking about here?



Great information here gentlemen. This kind of stuff gets me thinking, which is why I joined this site :)

You know, I was thinking that it would be best to adjust all (or at least most) cells in the VE table, even though some you can't collect data on like Marks' example of 400 RPM and 100 MAP; or 3200RPM and 20MAP. I was thinking it would be best to adjust all cells whether you got data in those cells or not, that way you could avoid spikes and dips in the VE table, but now ya'll got me thinking that maybe this is just not necessary or ideal to do the VEs that way. I guess really the data is the final judge, as dave stated. Now your thinking! Take your BLM readings and insert them into Daves Speadsheet, of course not all cells are filled in, look for patterns for low or high BLM or perfect and fill in entire spreadsheet to adjust not only cells with data but complete VE fuel table. Rinse and Repeat...

In the end data is king and the engine will run better with correct fueling. But in the final stages fueling will not be exactly smooth. Point of smooth tables was easier to tune to what engine wants! Data will be consistent, this way all the varibles will work properly. What happenes if you enter PE when BLM was changing from 128 to 168 to correct for wrong VE table? Well you don't get proper PE! Remember everything is an adjustment to main VE table, AE, PE, DFCO, choke... everything is an adjustment off main VE!

Also important point for anyone reading this, this is theory of 1227747 $42 VE. Other ECM/PCM may have areas that are not smooth nor are they supposed to be, for instance a PCM with 2 fuel tables for Idle and Off Idle, Off Idle should be smooth, Idle will not, there are areas that have to be close for transition, same for 2 spark tables. Other masks have other adders or subtracters that have to be considered.

[Ronny]

I believe you always want some value in Table 2. I used #5 for 400-3600 rpms adding balance to table #1 from #2. The idea is that there always has to be some VE in the adder table in order to have the VE lean out at high RPMs. If the ve adder table is zero, you cant reduce the VE after you have gone off the edge of the main table. 4000-4800 RPMs my adder would scale down like 45 @ 4000 35 @ 4400 and 25 @ 4800. Once youve done this you can leave the second VE table alone below 3600 rpm. Just work with the main VE table #1

[EagleMark]

Good tip Ronny! :thumbsup:

Just last week I had a motor worthy of tuning at these RPM and that's exactly what I had to do or Wide Band AFR would not stay steady, kept getting richer.

[78monte]

*20141012_121850.jpg*(95.9 KB)*

Attachment*

How does this look

[78monte]

*20141012_121850.jpg*(95.9 KB)*Attachment*

[78monte]

Sorry im having problems with the pic

[78monte]

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[dave w]

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That looks OK for a starting point, generally an engine at low RPM / light Load will need less fuel than an engine at high RPM / high Load. Engine modifications like aftermarket intake / exhaust systems might change the VE table.

dave w

[78monte]

This is after I smoothed then added the addr then smoothed again any suggestions im just trying to get a starting point being I havnt got the new ecm yet or the cables hardware I need

[78monte]

Anyone?

[dave w]

Good job on figuring out how to smooth in TunerPro RT. Not everyone gets that far with TunerPro RT.:thumbsup: A starting point is just that, a place to start. Collecting a few data logs will be helpful with understanding the VE needs for your engine.

dave w

[hammertime371]

hey guys... Ive been messing around with my tune and found this post. I added the 2 tables together and see im over 100 in some cells. So does this mean I should lower the bpw and check again?

[dave w]

After adding the VE2 table to the VE1 table, ZERO the VE2 table parameters!

To be on the safe side, you could reduce the entire VE1 table by 2%, then increase the BPW parameter by adding 2 to the current value and see what happens in the data log.

dave w

[hammertime371]

ok thanks dave ill give it a try...

[hammertime371]

Im having good results with this...seems to have helped the cold start issue... however at what point do ya stop increasing PW and add more fuel pressure instead.. I went from pw 127 to 136 at this point and dropped all ve cells by 10 points

[dave w]

Im having good results with this...seems to have helped the cold start issue... however at what point do ya stop increasing PW and add more fuel pressure instead.. I went from pw 127 to 136 at this point and dropped all ve cells by 10 points

I think most '7747 .bin files will have a BPW of about 135. I think 145 is a safe upper limit for BPW, then increasing fuel pressure would be a good plan. Lower the BPW, if the fuel pressure is increased.

dave w

[hammertime371]

What would the point of adding ve 2 to ve 1?? eliminate a table? would it be like driving in PE mode all the time? with a racing vehicle or heavily modded engine fuel milage would not matter then.. otherwise its best to stay with 2 tables??

[dave w]

What would the point of adding ve 2 to ve 1?? eliminate a table? Yes.


would it be like driving in PE mode all the time? NO!


its best to stay with 2 tables??Depends on how much tuning experience the tuner has.

dave w

[1990slowverado]

So several years later this post will make its way back to the top if the thread list. Haha.

I have been trying to tune my truck for the past couple years. I've only been doing by VE table and have been struggling. I haven't been able to get many of my Block Learns at or around 128. And I've been fearing I'm working against a vacuum leak or some sort of mechanical problem. Truck has been burning its fair share of oil, and likes its gas (I have been feeding it 90-91 octane rec gas)

It's been awhile to remember what I initially in the bin to start tuning my new heads and cam.

Cam: Summit K1103
Heads: Dart 10021070S
And apparently my engine is .040 over.

ARJT bin on 7747 ecm. $42-1227747-v5.2 xdf.

I have had the egr turned off for while now. All the typical tuning stuff turned off as well (except PE seems to always activate, its annoying).

I have done several datalogs and fuel and some spark changes over the course of a couple years and I just feel like I'm not getting anywhere. It runs "good", but not much better than stock, and has the bad mileage and oil drinking problem... didn't before the heads and cam swap. All new parts were used, new timing chain set, and the heads were assembled by the local machine shop.

So back to the fueling thing. I'm going to try and post a picture of what my current fuel table looks like right now. My VE 2 Adder table is not zero'd out. For some reason, in the beginning of this project when I was setting the bin up, I could've swore I added the tables together. Maybe not, too long ago for me to recall. If anyone wants, I can post a DL. I've read a lot in this forum, and don't know if I'm just not getting it, or if I'm just screwing myself up lol. Any help is appreciated of course.

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