Phil99vette

iTrader: (11)

What kind of curve are you guys running on the timing tables? Do you guys pull a couple of degrees timing between 4-4800?

SlickVert

iTrader: (5)

Phil,
Good question.
Also, what is the recommendation for timing after peck HP to keep the power from dropping?
Hopefully some experience Tuners will give us some advice.
Bob

Phil99vette

iTrader: (11)

I thought someone had said take 2-4 degrees out 4000-4800 or so...

foff667

iTrader: (2)

yeah i usually run 22-24 at peak tq and run it up after peak tq to 27-28*

SSpdDmon

iTrader: (10)

Yeah, I pulled a little timing around there and then added a little to the top end by hand blending it in. Also, it's like the GM engineers kind of stopped correcting the table at about .80 grams/sec on mine (2002). As a result, I have a section where the timing goes down to ~18* for an rpm row and then goes back up a degree or two around .84 grams/sec. If you had to pull timing back to 18* at 4,400 rpm & .80 grams/sec, why wouldn't you have to have equal or lesser timing at 4,400 rpm & .84 grams/sec (tune reads 19.5*)? My guess is they said, "The car won't hit those cells (in stock form), so why bother changing the rest of our guesstimated table?"

Tripintaz

when my z06 was bone stock it only hit a peak of .745 gms air/cyl. I also noticed in 3rd gear between 5000-6000 the gms air/cyl fluxuated between .62x and .74x....kind of strange but the timing is all the same in those tables anyhow so the spark advance did not change.

Patrick G

iTrader: (14)

Because peak cylinder pressure occurs at peak torque, many tuners will pull a few degrees of timing there to keep detonation at bay. Phil, with your big cam, I would expect your peak torque window to be occuring between 4800-5400 rpm. Wherever it is on your car is where you want to attack the timing.

By the same token, history has shown that our motors like a little richer A/F ratio right around peak torque too. When it's all said and done, you might be running 12.5:1 at peak torque and 13.0 everywhere else and 28 degrees of timing at peak torque and 30 degrees everywhere else.

hotrodrx7

iTrader: (13)

I recently had my car dyno tuned and we advanced the spark until it showed a little knock then backed off. We ended up with 28-29 at the torque peak (4800 rpm) blended up to 31 at redline. (high octane setting)

Tripintaz

those of you running 28ish @ peak torque and 30ish everywhere else.....would this work on a STOCK LS6 to gain HP? Right now I have 22 degrees of timing at peak torque and 25 degrees after that until redline. I did not change the timing below 4400 rpms. Should I tweak my timing table some more?

ringram

depends on what gas you are running, heads, temps etc.
You can try it and see. Its best done on a dyno though.
If your timing isnt optimised you will gain power at all rpm/load points until it is.

Tripintaz

i always run 93oct chevron. Headers will be installed soon. I have a 160 stat and K&N intake.

redtail2426

iTrader: (10)

if you have a z06 then dont add in any more timing.The combustion chambers on ls6 heads are more efficient and dont need as much timing.If you want to run 28* then go right ahead but i will bet you will not gain anything at all,and will probably actually lose some power.I remember a guy tried this he added a couple degrees each run on the dyno,showed no kr but no gain either.22-26 i would say max on ls6 heads.

hotrodrx7

iTrader: (13)

FWIW, I have ported LS6 heads milled to 61cc, and an F11 cam. After the base run, with a mail-order tune on the PCM, the first thing we changed was the timing. It picked up 20 HP and 25 Ft-# all across the graph. From that, I would say that LS6, or any heads for that matter, would respond to timing changes depending on the base numbers and all other mods. I still would not recommend doing it any other way than on a dyno with a competent tuner.

BLK02WS6

iTrader: (2)

I pull some timing in the torque range - how much and exactly where varies depending on the mods. The longer a car takes to pass through the torque range (stock or few mods) the more I pull. I usually start off with what experience has shown me to work for the mods on the car, then I let the dyno tell me what each car likes by adding a little and seeing what happens. Each setup is an individual and you really have to treat them as such.