Timing Questions

[NewV]

What are the best PIDs to log for timing and what tables in the tune file are they best compared to when reviewing logs?

I have added 2-3 degrees timing but having a tough time seeing it in the logs. The car feels different so I know the timing is in there but the actual logged values seem to change very little. I have added to the High and Low octane tables.

Also how much timing is too much?

Should you add till knock appears?

Thanks

[Tordne]

The high and low octane tables are the place to be looking at your spark. for PIDs log either the default SEA.SPARKADV (recommended) or you can also log GM.EST_RUN_DMA.

Spark really is best done on a load dyno. You get to a point where you are generating maximum power/torque, then there is a plateau where you don't yield any more, then you get to the point where you can lose power and also invoke knock.

[ringram]

Speaking of timing on dyno cells.
Even holding in one cell its real hard to see whats up, the torque numbers jump all over the place its like trying to hold a piece of paper still out the window while traveling at 100kmph. But you can definately see the trends and kind of the best point. Takes a while though.
I think next time Ill definately use the blending function to zero the whole table in fast then work more finely on key area's.
Does anyone have any recommendations for dialing the table in as efficiently as possible.
I started a little too slow and overheated the dyno and melted my tyres. Hehe, in the end I was talking about 10 sec per cell. Maybe 30sec at the start. Also forget going in 0.1 increments the variation is too much to be able to define it at that point. Go in 1 deg increments.
I found I was running too much timing for the most part, maybe around 5*. I wasnt getting much if any KR, just a degree or two here and there.
I wound up at the min timing for the most torque, which is known as MBT and is the recommended timing from what I understand.
That was on a dyno dynamics dyno.
Maybe a hub dyno will get around overheated tyres and perhaps make things more stable?
Anyone else got any dyno tips?

[The Alchemist]

I also use a dyno dynamics dyno and always use MBT when tuning any vehicle. Knock head phones also help a lot, nothing like the human ear as a tuning tool to detect knock! I go in 1 degree increments until I see no change going up, sometimes only 2 or 3, then lower until I see the torque drop away which it usually does suddenly with only a degree of change when it does. You need a steady right foot too :) Once you get a few key points done on the map you can get a feel for what the engine wants and fill in the boxes as you go checking every now and then to be sure.

Also how much timing is too much?
Best you visit a good dyno operator I think, not something you want to muk around with yourself. Standard maps are usually to advanced on the manual LS1's for 95 octane but some of the auto LS1's are 4 to 5 degrees retarded for 95 octane, so it can vary a lot....

Should you add till knock appears?
DEFINATELY NOT !