Cruise AF and VE tables

[ScarabEpic22]

I would smooth the low octane table and add maybe 3-5 deg to the high. As justin said, 10 deg is a lot, 8 is still too much. Start with baby steps and you will be much happier.

[Telco]

The latest tune is working great. The low octane table was smoothed, and the high octane was set 8 degrees over the low in the appropriate areas. Latest scan showed a max of 3 degrees KR and only under WOT. Now I can begin the baby steps and get it perfect. Thanks for the help with this so far folks, I'll be posting the final tune on the board for anyone interested.

[cmitchell17]

I couldnt notice anything from adding any timing on my 5.3, but I don't have a dyno or anything else to tell a diffrence.

One thing I did was use a newer timing table used in I think the 02+ used a smoother timing table. The 01s had a diffrent timing table.
You can't really tell which year had the most timing or the least it just changed all around usally only about 1 or 2 degrees in the normal airflows but in the .60-70 airmass and above the older tables usally had more timing and on the 04+ has less timing in the high airmass. I would guess to aid traction control.

I would guess that the best timing table to use would be the 04+ as they have not changed that one for the lm7s. Im pretty sure the motors are almost exactly the same for 04-07 same heads compression.

However on top of the stock timing I added about 20% timing from the optimal timing table so its raised about 1-2 degrees in most areas as I run higher octane gas and a higher octane always requires more timing as it burns slower.

[Telco]

Crap, don't have it after all. I adusted the fuel mix under PE to a richer level to try and knock out the last bit of KR in case it was too lean, and wound up getting more knock. Looks like I'm getting up to 8 degrees now.

What affect does optimal timing have on the works? I see that in some fields the optimal timing map has more timing than the same high octane timing map. I've readusted the F/A mix back where it was and plan to remove a bit of timing, but this will just put the optimal timing map further out. I've considered copying the high octane map to the optimal timing map to see what would happen, but as I don't understand it I'd like more info first. Thanks.

[cmitchell17]

I wish I knew exactly where the table came from. But from what I think its a table that the computer uses the figure how far the commanded timing is away from the values in the optimal table.

Im guessing if the commanded timing is far away from the optimal timing the delievered engine torque is going to be lower and if the commanded is close to the optimal timing the delivered torque is going to be higher.

So if this is true this means gm found the timing that would make the best torque and this optimal timing is it. But what conditions was this tested in? Cold ait hot air high octane low octane. My guess would be that is would be tested in the worst conditions becuase of the factory conservitive tuning.

Although in some places very light airmass, optimal is lower than the high octane.

But this is all just a guess?

[Telco]

I dunno. At some points the optimal timing is over 50 degrees, which seems high. Going to knock timing back a bit in the high octane table to see what I get on KR after work today. Might try just copying selected high octane tables to the optimal timing to see what effect it has too.

[cmitchell17]

From what I heard at very light loads 50 degrees is what it needs, but it seems to drop sharply as load increases.

[Telco]

I give up. I pulled timing and pulled timing, tweaked what I could, and still get the knock. Last night I put the factory tune back in, with its timing tables going as high as 51 degrees, and got less than 2 degrees KR which can be attributed to the spark plugs still needing to be changed. My dad didn't want to run the AC Delco plugs I was going to put back in, so I took them back. Decided that I'm just going to make the transmission and exhaust system adjustments he wanted, advance timing 4 degrees across the board in the high octane table, and call it quits. Every adjustment I made otherwise either made it worse or made no change, except for one tune, but none of the adjustments worked as well as the factory tune does now. Feels like it has the most power it's had since I've had the truck. Evidently I suck at tuning. Oh well, can't be tops at everything I guess...

[BlackGMC]

Naw you don't suck, you just need to tune with a wideband...

[Telco]

Heh heh... I know, just isn't in the cards right now. Thanks.