Corvette CCM Reverse Engineering Anyone?

[-=Jeff=-]

I've only touched one and may never again, but if I ever get vanity plates for mine they will be "ZR-N0NE" because in it's current configuration it would easily best any stock LT5 and most of the modded ones. I would love to own one for nostalgic aspirations, but knowing that Lingenfelter has bought up and is effectively bogarting every last piece of remaining engine parts GM owned makes it something I couldn't afford to drive the way I would like to.

Not sure Lingenfelter bought them all. Jerry's Gaskets has tons of parts. Only had to find parts, CCM, ECM and Ignition Module, but the IM is pretty stout.. As for Power, yeah I only have headers on mine and 4.10 gears.. I did other mods as my last vette (89 L98) had a built Miniram motor. I do know one ZR-1 ( another friend of mine) that coule give you a good run.. it runs 10.5's in the 1/4 (on stock gears I think)..

Alright, CCM Messaging:

I want to thank everyone for the help I have received. I have looked at a couple messages with the CCMs I have. So of this info cam from NomakeWan as well
I am pulling this form the ECM Simulator that NomakeWan posted around page 18. I was woking on the Arduino to test the messages which is why they are formatted the way they are

Edit: Checksums may not be correct at the end, witht he simulator I had it always calculating the Check sum as I kept changing values and compiling, so that was the quicker way to get the correct messages

94-95 ECM->CCM message.. LT1 only
0x41, 0x67, 0x02, 0xF5, 0x00, 0xCD, 0x87, 0x01, 0x00, 0x00, 0x00, 0x00, 0x88, 0x00, 0x48, 0xFF, 0xFF, 0x00, 0xFF, 0xFF, 0x40 

1992-1993 ECM->CCM
 LT1 Message 0x41, 0x64, 0x01, 0xF3, 0x00, 0xCD, 0x60, 0x01, 0x00, 0x6F, 0x0F, 0xD6, 0x83, 0x00, 0x51, 0xFF, 0xFF, 0x13
I found this message was happy with CCMs set for LT5 or LT1. I tried to twiddle Byte 10 MSB, but no changes as I could see

1990-1991 ECM->CCM Messages 
L98 Message = 0x41, 0x61, 0x00, 0xEC, 0x00, 0x39, 0x39, 0x01, 0x00, 0x00, 0x00, 0xB4, 0x00, 0x39, 0x12
LT5 Message = 0x41, 0x61, 0x00, 0x00, 0x00, 0x4F, 0x54, 0x01, 0xAD, 0x80, 0x76, 0x7A, 0x00, 0x4B, 0x13
1990-1991 Byte 10 MSB must be  set to 1 to tell CCM it is a LT5 (Tested and Confirmed with above messages)

My final message was a pull from the 1995 ZR-1 I helped fix due to having a LT1 CCM. What I found interesting was the message:

1995 LT5 (I assume 94 as well)
0x41, 0x64, 0x00, 0xEF, 0x00, 0x51, 0x47, 0x01, 0x08, 0xCB, 0x14, 0x81, 0x7A, 0x00, 0x46, 0xFF, 0xFF, 0xAD
Same size and length as the LT1. I no longer have a 94-95 CCM for test purposes.

I am debating on buying a 1994 CCM for testing purposes, but have 4 others so not quite sure I need it. I need to finish my test bench which will add functions to the ECM Simulator for some of the cluster displays..

EDIT #2. ECM messaging will be the same for 92-95 LT5s. they new at the end of 1992 the ZR-1 would end in 1995, so all remaining motors were built in 1993. If the LT1 and LT5 shared messaging in 92-93 that would make sense that the flag int he 94-95 CCM changes the whole message detection. I still believe there might be a flag in 92-93 but thinking now maybe not

EDIT #3: you said you would do a vanity plate: ZR NONE.. My Expanded Antique Plate is ZR ONE.. LOL