This is a rather long post I’ve decided to put up to give an in depth knowledge dump on how the conversion was done. If you have the attention span of the average tik toker, this probably not for you.

Over the last couple of years I started getting a more in depth understanding of the GM ECU & TCM code for the GM E38/T43 computers via a program called Ghidra, this is a program that can reverse engineer and decompile code from known processor architectures, not just PC’s but integrated cpu’s in automotive, home appliances etc.

It was from here I decided it was probably time i revisited trying to get an early VZ V8 to work with the 6L80 natively, I had intentions on trying to do this back in 2018, but time & knowledge was something i was very short on. Cue, many years later I now posses both knowledge, ability, time and a little disposable money to do it!

This led to me picking up slightly damaged VZ SS with the required 6lt/4L65e, Apparently it had a bit of an excursion off road when the owner fell a sleep, resulting in some damage to the front/rear bumpers and drivers side rear wheel & swing arm.

I’ve always thought it would be possible to get the 6L80 to work in the VZ 6LT cars is because it runs an E38 ecu just like the VE did when it was introduced in September 2006 with both a 6 & 4 speed auto (exported to Saudi Arabia) along with Manual options. I already knew the box physically fits in the tunnel because I have converted a few VT-VZ car’s already.

The biggest difference however is that the VZ model encompassed support for the 5.7lt LS1 with it’s P59 ecu & the Alloytec’s Bosch ecu, which meant wiring & modules to support all 3 types of engine combinations.

With a LS1 motor there is a PIM (Powertrain Interface Module) that translates data from the ecu’s native VPW protocol to UART protocol for the dash cluster, ABS & BCM modules to get data. So for the E38 ecu to talk to those same modules the PIM module now converts from CAN to UART, the ABS module went from talking on the old UART to now CAN directly, similarly things like the cruise control stalk went from the BCM to the new PIM too.

The Hard Part / Nerdy Stuff

Delving into Ghidra & selecting the relevant CPU architecture type for the ECU binary file the program can then start to decompile the file & with any luck it find’s links to instruction sets & cross-referenced values.

While Ghidra doesn’t tell you what all the numbers mean, since they can be different based on the specific use case the calibration was written for, it does help if trying to follow a structure or routine from 1 calibration to another. Similar blocks of data are often always together across different calibration/part numbers even if they located in different locations in the calibration file.

Now having the decompiled file doesn’t help on it’s own without having something to actually reference back to, so luckily some one had passed on a couple of factory style definition files that gives names & often descriptions to what each parameter is. It is with information that it becomes possible to understand what the values mean or what a simple 0 instead of a 1 means. i.e Switching something on or off.

Then it’s a matter of pattern recognition in the hopes that similar values & code structure are used across the different calibrations that GM has from all the different vehicle types. i.e Holden, GMC, Corvette, Camaro etc.

Tuning Software

From the above, it’s possible to add these “missing” options to tuning software, in my case since I primarily use EFILIVE for tuning & since they allow for users to add in options via a CAX file. The cax file basically allows the end user to add in tables or maps that are not already defined in the software.

In this case to get the 6L80 to work with the VZ ecu we need to make some changes;

1. Turn off NSBU (Neutral Safety Back Up) Switch
2. Turn on IMS (Internal Mode Switch)
3. Automatic Max Gear from 4 to 6
4. Gearbox Gear Ratios (Optional)
5. Vehicle Speed Sensor Pulses per Revolution 40 to 36
6. Transmission Type (Optional)

1 & 2 above are a requirement because the 4L60/65 use a NSBU on the side of the gearbox, but the 6L80e doesn’t. Instead it uses an IMS inside the gearbox that slides when the shifter linkage is moved. The remaining settings feed information into things for torque mgmt & speed calibration settings.

While i didn’t bother to test not changing the above settings with the 6l80 wired in, it made no sense not to since when looking at a factory 6L80 ecu tune the new values are what are configured, it would appear even the early Holden calibrations didn’t have the correct gear ratios & transmission type selected on the 2006-2008 VE models.

Wiring

For the wiring, I pulled the engine harness off the motor & stripped out all the old NSBU & trans plug wiring along with the wiring to the original T42 trans controller that sits in the passenger kick panel. A majority of the wiring to the T42 controller is repurposed, In this instance I simply terminated the wiring to a new deutsch connector that sat on the engine bay side of the firewall. This then allowed for me to make changes if needed during testing.

New transmission plug & wiring re-wrapped in new automotive high temp tape.

6L80 Install

Installing the box is simple, just unbolt the old 4 speed and install the new 6 speed with matching torque convertor, original shifter rod will require some slight adjustment so that it doesn’t rub along the side of the case. A new trans mount & modified tailshaft then needs to be done as the 6l80 uses a larger 3 bolt spigot.

CAN BUS – Make it, break it or fake it?

Now with that done, the ECU side should be happy right? Sort of, it’s really going to depend on what your donor transmission came from. At the time of starting this conversion project I was under the impression of 1 simple fact when it came to the TCM’s that are in these gearbox’s.

There was 2 year ranges that were programmatically compatible with each other, that being years 2007 to 2009 & then from 2010 to 2017 i.e end of the VF’s. This meant that you could not install a 2010 gearbox into a 2007 model car & have it work, It would come up with a U0100 or P0700 DTC, Hell even a 2009 gearbox tune will not talk which always bothered me because it didn’t make sense that by simply performing a full OS flash with an 07 or 08 tune into the 09 techm it would work.

The solution to this problem it seems was always in the code. In every ECM & TCM operating system is the CAN ID broadcast data, now this does vary from 1 OS to the next, but luckily the majority of CAN ID’s needed for the ECM/TCM modules to talk/listen to each other have not changed too much over the years.

So what I found was the CAN ID’s that the ECM\TCM were configured to use for it’s “State of Health Monitoring” between the modules was different. SOHM basically runs as a check to confirm that the other module hasn’t disappeared, If it looses communication it triggers a check engine light & potentially limp mode.

So with this knowledge I started with a 2008 TCM OS as my baseline to confirm communication to ECU, gearbox would shift etc, then changed over to a 2009 OS.

With changes to the 09 Calibration to match similar settings to that of the earlier 08, I was no longer getting a U0100 code or 3rd gear limp mode. Great news! Now I wonder how far can i can push this?

Slight side track…

So I grab an older 06 ecu from my collection & install it in my vy ute, This effectively runs a 2011 VE ECU & TCM OS combination since it’s a 6lt/6l80 combo. I change out the ecu & flash the VZ tune file in with some basic injector & map settings to get it running, multiple flashes later & that too now communicated to the ECU with no error codes. I could shift into 3rd gear via tapshift and reverse in & out of my workshop. When i got the settings wrong, I would momentarily have reverse and 1st gear before it would lose forward gears.

I’ll be doing some further testing in 06 VE soon by replacing the ecu with a later year thanks to it’s larger injector support to see if i can get it to work & be happy with all the other CAN modules.

End Result

Strap in kid’s, this ones gonna be a long one.

Something I’ve played with for a few years, specifically in the late VZ/VE E38/E67 ecu’s is the ability to edit the Pedal to Throttle mapping correlation.

With the arrival of drive by wire, the accelerator pedal was now physically disconnected from the throttle body, so it was now possible for vehicle manufactures to alter the response & power of the vehicle independent of the drivers “demand” (foot), Which is why DBW cars originally copped a bad wrap because people noticed the lack/loss of “feel” from the pedal in regards to throttle response.

So, why did manufactures go to it? With the integration of more safety orientated or performance enhancements like ABS, traction & launch control it was now possible to alter the pedal response to either restrict throttle opening or give more for the same pedal movement, you can start to understand why they did it.

Also when you think about it at the most basic of levels and like everything in life it always comes down to the Dollars, specifically WARRANTIES. If you can reduce the potential for abuse on the drive line, you stand to save a fortune as a manufacturer on potential faults/repairs.

Anyway, on to the cool stuff. What I’m about to show is a couple of examples of power limiting rather then power adding. The reason for this “limiting” is because the setups are both Supercharged V8’s, so there is sometimes a need to limit the amount of boost the blower creates, i.e over-driven blower.

Vehicle 1

The first car was a VE E3 Clubsport with a stock LS3 Auto, bar a cat-back exhaust with over 140k km’s on it at the time the Harrop FDFI2300 supercharger went on, with further mods to happen at a later stage, I wanted to allow the owner to get used to the power (his dad & my preference). So no valve spring or fuel system upgrades as yet.

After the blower first went on I started by doing some small load testing at various rpm’s to see what the maximum boost was, I expected it would be well over 10psi since the blower originally came off my own Cam’d 6lt ve ute making that.

Since it still had stock headers & cats it made north of that at around 12.5 even with a larger blower pulley fitted to reduce the boost, which is why I moved on to do some testing with restricting the throttle opening. This is done pretty easily in Efilive by adjusting the pedal to throttle mapping.

What you can see above is the factory calibration & how below the 2500rpm row, the values are lower, I can only assume to smooth any large pedal movements at low rpm. The numbers themselves do not correlate to a 1:1 rate to the throttle blade opening.

In the next 2 pictures you can see that at 2600rpm the Accelerator Pedal is at 100% however the Throttle blade opening is only at 69%. This is achieved by modifying the throttle response map.

As expected with the 6 rib drive setup on this car, as the rpm’s started to climb the boost started to drop off. Luckily because the blower was capable of generating more boost then needed, I could tailor the boost curve how i wanted by simply manipulating the throttle mapping, which is why from 4500rpm I start to allow more throttle opening to maintain boost pressure.

The end result was a 130whp gain for on a complete stock LS3 motor/exhaust combo.

Vehicle 2

The second car is my own VE Ute which got upgraded to the Harrop FDFI2650 with the LSA drive belt setup, this is a more aggressive combination setup with full exhaust, flex-fuel & bigger motor with a Fore Innovations Twin 450 pump setup. All though it does have an aftermarket converter & trans cooler it still has a stock 6l80e.

It had previously ran 10.5 over the 1/4 with a touch over 600whp on pump fuel in 2015, for now I’ve just been filling it up with E85 because it’s not driven on a daily basis.

Since the ute has the same Operating system as the Clubsport it had the same base throttle map configuration. So below power runs were done after severely restricted throttle opening until 6500rpm to get a baseline.

Further playing in the Pedal response map I eventually got to my desired boost to pedal correlation. While also limiting the response at lower throttle movements to make the car easier to drive, since with the larger 102mm throttle it can be very touchy for traction if your not careful.

Throttle limiting in action
APP = Accelerator Pedal vs ETCTP = Throttle Opening %

Couple more tweaks to Pedal Map with the end result being a nice linear power graph

So after many years of putting up with the lack luster battery life that comes with the HP Ipaq unit that controls my dyno, I thought I should finally do something about it.

Having previously worked for a logistics company that did a lot of scanning of freight with Motorola devices, I did a quick search on ebay & found a bunch of MC75 units available for a reasonable price, so I took a gamble & ordered 1.

A week later the unit turns up, sadly no charging cable or dock came with it, so another week of waiting for that to turn up before i could play with it.

Once the dock arrived & the unit was charged, I loaded up the original command module application via it’s micro-sd slot & updated the applications parameter file with my EDM bluetooth address, fired up the app & success…

Well sort of, at first i had no control of the dyno with my existing config file, so i tried a different PDA model that i knew the app supported & presto! I had full control just like normal, However the Motorola display having twice the resolution of the original HP unit at 480×640 vs 240×320 made it “box” the app into the top left corner of the screen like the simulator picture shows.

I noticed that the text in some of the screens was much larger, so that told me it was auto-sizing some of the text fields correctly at least. So not wanting to accept this limitation, I wondered if it would be possible to edit the original application code.

So after spending a few hours looking for & testing some Visual Basic & Dot Net de-compilers I eventually settled on a program called dnSpy.

It can break down the original exe program & present all the instructions & pages that the application uses & then recompile the app back into a executable again after making changes.

OK then, this could actually be possible.
What i found was the program seems to be broken down into a few area’s:
Orange Box = Comm’s & system related instruction data
Yellow Box = Event related data for each page
Red Box = Page layouts, set’s page size & picture box sizes

Since the app was created as a Microsoft form design, the interface starts by setting a background picture, then overlays additional picturebox’s (buttons) on top, they were easy to modify to the new locations I needed by just doubling the X & Y locations & picture size. I then compiled the program & loaded it to a windows mobile emulator to test the change.

Success! this got the buttons in the right location, but the button images and background were still half the size they needed to be, so at first I tried extracting all the built-in pictures & simple doubled the image sizes by 200%, this worked at first for a while during testing until I got the main executable to around 7mb in size & the application would then crash the emulator, this effectively wasted 5 days of me playing with it after work.

So more research was needed & what I found was that this was due to the way the images are loaded into memory on the device, so i had to find another way.

Again a little more googling & the answer was relatively straight forward. I just needed to set the picturebox image to stretch with the following line for each image.
this.pictureBox.SizeMode = PictureBoxSizeMode.StretchImage

But wait there’s more! rather then having to rely on using the original Dyno Dynamics supplied cab install file & then copying my version over the top, I went & created a new cab installer package with my own updated file.

If your based in Australia & want to purchase a tested & ready unit. I now have units available here.