So I've been following the great work that Tom H and others have been doing on the OBD2 LT1 ecu however I have not seen any discussion on this particular topic. Regarding datalogging, I realize there is a generic OBD2 communication layer which is very limited in data rate and selections of PID's, pretty much useless for tuning. A second layer that is GM specific that has all the "enhanced PID's" that is faster than the OBD2 but these are common addresses between different code bases, model years and possibly model types. Also, the data rate, while faster than generic OBD2 is still fairly limited at least based on what I've seen using my EFI Live interface. I know on the later LS1 411 ecu's commercial tools are able to communicate and a considerably faster data rate than the early LS1 computers, even so, still not that fast.

All that said, when GM was developing these engines and calibrations they must of had a much faster way to communicate with the ecu's as well as edit the calibration on the fly and have the ability to address any DMA not just the common parameters that are available on the TECH2. In the Bosch world they had what they called ETK which would typically sandwich between the processor/eprom and the ecu pcb, at least on older 1990's-early 2000's ecus. That setup had some sort of dual port ram arrangement and would also redirect the rom addressing to battery backed or EEPROM memory on the ETK board. With that setup you could log a very large number of ram addresses at very high data rates and edit any calibratable parameters on the fly using software called INCA. They also had communication protocols that although not as fast as the ETK, provided much higher data rates than the standard dealership level diagnostic tool as well as being able to log any direct memory address through the standard communication port (OBD1 or 2).

So:

1. Does anyone have an idea of how GM did it, i.e. did they have a development ecu like the ETK setup or was data access all done through the ALDL ?

2. Is there already a solution for DMA logging on these LT1 or even the LS1 generation of ecu's ?

3. What is the fastest data rate you can expect with either the 94-95 or 96-97 LT ecu with existing tools / software ?

Thank you in advance for any thoughts or comments on this topic.