E38 A6 to M6 vs Stock OS

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05-19-2021
50FordF1

Segment swapping E78/E67/E38 A6 to M6 vs Stock OS

Could someone help get me pointed in the right direction please. Years ago, thanks to this forum and the support of many of its users, I was quite successful in getting my supercharged LS1 up, running and tuned. I thought if I did it once I could do it again but I have to say the Gen IV ECMs have me at a total loss.

Here's where I'm at as of today:

I have an L96 iron block 6.0L with L92 heads out of a 2012 Sierra 2500 (a perfect candidate for FI) 58x reluctor wheel, VVT, A6, No AFM, with APP. It came with an E78 ECM Service# 12643636 and OS 12647731. As best as I can tell there was never an E78 ECM mated with a 4.8, 5.3, 6.0 or 6.2L and equipped with a manual transmission. I have every intention of using a manual. VVT will be deleted.

E78 ECM:
Problem 1: I've read numerous accounts of people swapping in T56 while using the E78 (or E38/E67) (with an automatic tune) and having issues with RPM hang during shifts and/or idle issues as a result of the missing torque converter. Simply selecting manual transmission in the tune has no effect and is reported to not work. You must use an OS from a car that was equipped with a manual.

Problem 2: To further complicate matters the VSS signal fed to the ECM from a T56 is generally not compatible. With the auto setup the VSS is processed by the T42 transmission computer and transmitted to the ECM across the GMLAN.

Problem 3: There is no custom 2 Bar SD OS for the E78.. Did I mention I'm going to turbocharge this motor!

Problem 4: No ability to control Fans.

Okay fine.. ditch the weirdo E78 and get either an E38 or E67.

E67 ECM:
3 vehicles use an E67 with a manual transmission. The Camaro ZL1, CTS-V and Corvette ZR1 all equipped with the LSA. Sounds like a good start but...

Problem 4: No custom 2 Bar SD OS or is this a problem? These vehicles are supercharged already. So this is seemingly a moot point (again I don't really know) as the stock OS already supports 2.5 Bar. Is a COS easier to tune over the stock OS? What about the all the extra sensors on the intake. Multiple MAFS, IAT, Barometric pressure and so on.. How many of these do I really need to keep? I assume all if I intend to run a stock OS.

Problem 5: These ECM's are really really hard to come by (both in Canada and the US). I've scoured car-part and anytime I do come across one no wrecker is willing to separate it from the motor (which is fair I get it). So you are stuck with an ECM from a Malibu or Colorado in need of a Tech 2 or MDI to reprogram it. In my neck of the woods (Canada) this is going to be a GM dealer at $130/hr shop rate and its a total shot in the dark.. I called 3 dealers in my area and none were confident it could be done to a bare ECM out of the car or had minimal experience doing OS swaps.

As far as which OS to load , it seems that if I use an E67 with Service# 12633264 that OS 12652955 from a 2012 Chevrolet Camaro ZL1, 6.2 L, 8 Cyl (available from HP Tuners repository) would be best. According to EFI Live ECM vs OS compatibility chart so long as I use a 2010+ E67 with Service# 12633264 I should be okay hardware wise. Earlier year E67 may or may not have different hardware guts.

Problem 6: By switching to OS 12652955 I now need a Camaro throttle body and a Camaro gas pedal. The pedal might be as easy as swapping wires D and F.. The throttle body I will have to purchase new.

E38 ECM:
Problem 7: Though more abundant, finding a used E38 with a manual OS already loaded has proven equally hard. Again, I would need to have the dealer load an OS for me on a random E38 but with so many E38 hardware variants out there I don't know which one and with which OS would be best for a M6 and FI. Service# 12633238 are common in Silverados and Express Vans. My best guess is a 2012 Camaro LS3 with Service# 12633238 running OS 12639270 would work.

Problem 8: Do I still need to swap out the throttle body. Same for the gas pedal?

Problem 9: How many credits does it cost to upgrade an E38 to the 2 Bar OS? I'm out of the loop and nervous to click anything.

Problem 10: Whats the deal with segment swapping. Is it possible to use a 6.0L E38 ECM say from a Express Van and do a segment swap on the transmission segment cutting out the need for a Tech 2?

Honestly, I would have never though it would be so complicate to swap in a M6. Between the ECM hardware variants, multiple OS, multiple Service# and the fact that the new VVE tuning table looks extra complicated I'm really tempted to revert back to what I know and get another E59 ECM, change out the 58x for a 24x reluctor wheel and go with a good old fashioned cable throttle body. But what fun is that!
Is there strong justification to use an E67 over the E38 and eat the cost of a new throttle body, APP and whatever other additional sensors its needs. Is it really that much better, even without a custom 2 Bar OS?

Someone please point me in the right direction. What magic combination of ECM, OS, Service# and VIN is going to get me rolling.
05-20-2021
50FordF1

Here is a list of PN for various configurations I've come up with. Based on the below it seems that the E67 is my best choice in terms of throttle body and gas pedal compatibility.

If I used OS from a LS3 Camaro/Corvette with an E38 I would definitely need to get the 2173153 throttle body. However, the gas pedal are the same between LSA and LS3 so perhaps its the vehicle wiring thats slightly different hence the APP Pin D/F swapping.

Bringing me back to my original question.. Is the E67 with OS 12652955 the best option despite not having a custom OS from HP Tuners?

Vehicle Throttle Body Gas Pedal Service# ECM OS

2012 Sierra GM GENUINE 2173151 {#12601387, 12629992} GM GENUINE 23362231 {#20972082} S# 12670036 E78 OS 12647731

2012 Camaro 6.2L Supercharged GM GENUINE 2173151 {#12601387, 12629992} GM GENUINE 22741799 S# 12633264 E67 OS 12652955

2012 Corvette 6.2L Supercharged GM GENUINE 2173151 {#12601387, 12629992} GM GENUINE 19417903 S# 12633264 E67 OS ??

2012 Camaro 6.2L GM GENUINE 2173153 {#12605109} GM GENUINE 22741799 S# 12633238 E38 OS 12649046

2012 Corvette 6.2L GM GENUINE 2173153 {#12605109} GM GENUINE 19417903 S# ?? E38 OS 12647991

2012 Chevy Express GM GENUINE 2173151 {#12601387, 12629992} ACDELCO 84328657 S# 12633238 E38 OS 12635859
05-20-2021
50FordF1

Okay I think I'm making progress now..

Vehicle, Throttle Body, Gas Pedal, Service#, ECM, OS
2011 CTS-V 6.2L Supercharged, GM GENUINE 2173151 {#12601387, 12629992}, GM GENUINE 25858067, S# 12633264, E67, OS 12693469

There is a custom 2 Bar OS (OS 1250246) and this E67 uses the same throttle body as the one on the 2012 sierra. Im not sure about gas pedal but that can be sorted. Also no VVT or AFM in the stock tune.

My plan.. Buy a used E67 ECM from a 2010+ vehicle with an OS that is compatible with 12693469 using the EFILive cross reference guide, then have GM dealer program that ECU with OS 12693469 (from the 2011 CTS-V Supercharged M6), then upgrade the factory OS in HP tuners to 1250246.

Am I missing anything?? VSS compatibility? Fueling Compatibility?
05-20-2021
blindsquirrel

E67 VVE can be rescaled up to 315kPa same as any other VVE-based ECM. I don't get the fixation on the custom OS.

You can buy ECMs from various sources that will pre-flash them using GM SPS using any (valid) VIN you supply. Just find the OS you want, get a VIN from a vehicle that used that OS, find the correct Service Number ECM for that application. You do not need to buy a used ECM from a specific vehicle with a specific OS already on it. Any ECM with a compatible Service Number can be programmed with any of the compatible OSes. No trips to the dealership needed.
05-20-2021
50FordF1

Thanks blindquirrel. I'm not fixated on a COS I just don't know any different :-). My last tuning venture was on a Gen III running a 2Bar SD tune so the COS was required. Gen IV seem to have a great deal more functionality already built in. I'm early in the project and wanting to future proof myself as much as possible. If the CTS-V is the same E67 with the same service number as a Malibu, Camaro or Corvette, but also offers a custom OS, than at least I can upgrade later on down the road if needed. I just don't know enough to know if I actually need it or not!

Why would there be a COS for the CTS-V but not the Camaro/Corvette. There must be some advantage to the CTS-V COS?

From HP:
2.5 Bar MAP - Speed Density (E38/E67 ECM)This enhancement contains the following features:
2.5 bar (255 kPa) max MAP sensor support (calibration capability for GM 0-5V linear MAP sensors)
Rescaled High MAF table supports up to 15400 Hz with 300 Hz resolution, also supports airflow up to 1024 g/sec
New VE tables with 33 x 33 cell resolution each and configurable MAP and RPM axes (choose your own resolution)
Charge Temperature based VE multiplier table, configurable axis
TPS based VE multiplier table, 33 x 17 cells with configurable TPS and RPM axes
MAP referenced "Boost Enrich" table
Boost Enrich MAP threshold and hysteresis value
Both MAF and Speed Density mode supported
Boost based fuel cut, selectable MAP threshold cuts fuel to all cylinders when exceeded
Rescaled fan temperature axis 163-250F (73-121C), stock is 192-250F (89-121C)

Based on the description above I see 2 things of interest. The Boost Enrich on MAP and the other is re-scaled fans. Maybe I'll need them maybe not..
05-20-2021
blindsquirrel

Open a tune file to see if it's the right ECM type & has the OS upgrade available you're interested in, go to Tune Details, copy the VIN, paste VIN into parts catalog. Find what Service Number ECM it uses.

https://www.gmpartsdirect.com/oem-parts/gm-ecm-12678513

Scroll down to Vehicle Fitment, click expand.

If you take a 12678513 from a 2012 Canyon and program it in SPS with a 2015 Camaro ZL1 VIN it turns into a 2015 Camaro ZL1 ECM. Same Service Number means the hardware inside is compatible with all the calibrations that use that SN and can be programmed to fit any of the compatible applications.

The availability or not of a custom OS is OS-dependent, not Service Number dependent. A Camaro OS may have one available but not a Canyon - or vice versa - even though they both use the exact same hardware.
05-20-2021
blindsquirrel

Based on the used prices of that E67, I would be real tempted to use an E38.

https://www.gmpartsdirect.com/oem-parts/gm-ecm-12633238

Holy cow, look at that fitment list. 2011 Camaro LS3 has the custom OS available. I think, the only feature you would be missing is the E67's ability to control the LSA's bypass valve solenoid. And the bellybutton E38 is as low as $30 on ebay.
05-21-2021
50FordF1

Thanks for the replies everyone. What I wasn't sure about was the E38/E67 hardware differences. Could a V6 E67 ECM control a V8. But thats been clarified now. As indicated above any ECM will work so long as the service numbers match (ie its in the vehicle fitment list). :cool:

On that note, I lucked out and was able to find an E67 out of a 2010 Malibu with Service# 12633264 (aka 12678513) found on car-part for $40 and better still its in Canada. I still need to have a dealer program it but such is life. I was planning on using the VIN from a 2011 CTS-V Supercharged M6 that I found in the repository but will explore of the 2011 LS3 Camaro and 2015 Camaro as suitable options.

The other reason I was hungry for an E67 was simply because it looks to use the same 3 connectors as the E78. Ill confirm once I get the E67 in house. One less thing to have to purchase.

Us Canadian folk always struggle with parts availability.. A $30 part on ebay turns into $60-$100 by the time it crosses the border. Without fail. Every time. My last project I kept a running tally of costs and by the time all was said and done 21% of the project cost was shipping (just shipping, not tax, not duty.. UPS, Fedex, DHL, USPS). The other thing we miss out on are U-Pull-It yards; there just aren't any around anymore.
05-21-2021
blindsquirrel

Anything non-supercharged is going to be an E38, using the VIN from one of those would get you a file incompatible with the E67.
05-21-2021
ScarabEpic22

If you want to run a Gen IV engine and a T56, an E38 is going to be the simplest. E67 is really an E38 with the addition of VPW comms for vehicles that didn't have all modules converted to CAN conversion, and also had enough additional I/O to control the LSA S/C.

The Enhanced OS for E38/67s isn't needed even with a supercharger/turbo, but it can be a nice-to-have. Since you're starting from scratch (and also assuming this is a swap application), easy enough to use a base OS that supports it in case you want to use it at some point. Enhanced OS' have been a free upgrade for quite a few years now, I believe since ~2014 or 2015.

You do need to match the throttle body and pedal to the ECM calibration, so you'll want to track that down too. I'm thinking using the Camaro platform like you suggested will be a good path.

E78 was used in HD trucks and with some I4 cars (Sonic/Cruze). When paired with a V8, it was auto-only.
12-18-2021
Robstevens

Quote:

Originally Posted by ScarabEpic22

If you want to run a Gen IV engine and a T56, an E38 is going to be the simplest. E67 is really an E38 with the addition of VPW comms for vehicles that didn't have all modules converted to CAN conversion, and also had enough additional I/O to control the LSA S/C.

The Enhanced OS for E38/67s isn't needed even with a supercharger/turbo, but it can be a nice-to-have. Since you're starting from scratch (and also assuming this is a swap application), easy enough to use a base OS that supports it in case you want to use it at some point. Enhanced OS' have been a free upgrade for quite a few years now, I believe since ~2014 or 2015.

You do need to match the throttle body and pedal to the ECM calibration, so you'll want to track that down too. I'm thinking using the Camaro platform like you suggested will be a good path.

E78 was used in HD trucks and with some I4 cars (Sonic/Cruze). When paired with a V8, it was auto-only.

Can you actually reflash an e67 from a production car and use it with,say, an ls3? I have a gmpp crate engine and the gmpp e67, but want to go to pwm fan operation.
12-20-2021
ScarabEpic22

Quote:

Originally Posted by Robstevens

Can you actually reflash an e67 from a production car and use it with,say, an ls3? I have a gmpp crate engine and the gmpp e67, but want to go to pwm fan operation.

Yes, you'll need to tune it for your engine combo as I can't recall any LS3 + E67 factory vehicle combos.

What I don't know is if there will be other issues, like do you have an automatic trans using a GMPP controller? You'll need to check all of your wiring as the pinouts could be different from GMPP to whatever vehicle you use.
11-22-2022
04colyZQ8

just use a E67 from a 2007 CTS-V only came in manual, no vvt non boosted.. just swap in a LS2 TB, and use a CTSV pedal. tune it done:) I can flash it for you, I have gm software, and I am in Canada.. east Coast (Ontario)