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.