RADustin
February 24th, 2017, 06:22 AM
Greetings,
I've been way over due to compare what I've known for a little bit now about the differences in the TC tuning across early LS1 OS(say 1999) and later(2002, 12212156).
When I tuned my 1999 LS1, I wanted COS5. So first I made it 12212156 by using a stock 2002 corvette file, then applied the COS5. Initial fuel, ignition, and RAF tuning went fine, but I had rough drive-ability. It was mostly coming to a stop. If I eased very, very slowly (small deltaVSS), all was fine. If I pushed the clutch in quick and hit the brakes as in normal or aggressive driving, the engine would instantly turn off like the key had been turned off. MAP instantly hit ambient and the engine was dead.
I couldn't figure out the problem for a while until I decided to go back and copy table by table from the throttle follower and throttle cracker from the earlier OS to the later. Immediately things were much better and I quickly polished off any hiccups.
Fast forward to this morning(~2 year later), I'm having a similar problem on my brothers truck. Before I looked at his tables I wanted to know the difference in the early vs late TC and TF from the corvettes. So I made the simple attached document. I think you all should find it interesting.
What is most interesting to me is that the early OS doesn't really ever decay TC. I imagine the ecm uses the idle airflow learning to decay back the input from TC. The second most interesting thing I've noticed is that they are very similar other than the TC decay- so why wouldn't my truck come out of power without getting the airflow it needed? I don't have an idea for this, but I think there is something larger to be learned if I did know. The 1999 and 2002 engines should be physically the same.
Anyways, hope you all find this somewhat useful/educational. Feel free to chime in with any insight.
20779
I've been way over due to compare what I've known for a little bit now about the differences in the TC tuning across early LS1 OS(say 1999) and later(2002, 12212156).
When I tuned my 1999 LS1, I wanted COS5. So first I made it 12212156 by using a stock 2002 corvette file, then applied the COS5. Initial fuel, ignition, and RAF tuning went fine, but I had rough drive-ability. It was mostly coming to a stop. If I eased very, very slowly (small deltaVSS), all was fine. If I pushed the clutch in quick and hit the brakes as in normal or aggressive driving, the engine would instantly turn off like the key had been turned off. MAP instantly hit ambient and the engine was dead.
I couldn't figure out the problem for a while until I decided to go back and copy table by table from the throttle follower and throttle cracker from the earlier OS to the later. Immediately things were much better and I quickly polished off any hiccups.
Fast forward to this morning(~2 year later), I'm having a similar problem on my brothers truck. Before I looked at his tables I wanted to know the difference in the early vs late TC and TF from the corvettes. So I made the simple attached document. I think you all should find it interesting.
What is most interesting to me is that the early OS doesn't really ever decay TC. I imagine the ecm uses the idle airflow learning to decay back the input from TC. The second most interesting thing I've noticed is that they are very similar other than the TC decay- so why wouldn't my truck come out of power without getting the airflow it needed? I don't have an idea for this, but I think there is something larger to be learned if I did know. The 1999 and 2002 engines should be physically the same.
Anyways, hope you all find this somewhat useful/educational. Feel free to chime in with any insight.
20779