Tuning Spark 12P

[vc81]

Can someone please explain why the spark advance histogram figures displayed after a log are not the same as the main spark advance table?

Is the main spark advance table like the commanded value and the spark advance histogram values are the actual values that were achieved?

[Holden202T]

"in a perfect world" ........... the histrogram should match the main spark table.....

you need to be a bit more specific though, because theres plenty of things that can effect (add or remove) timing .....

is it a certain rpm it does it or only at idle or only when WOT etc ?

[vc81]

10degreesparkmap.JPG (110.33 KiB) Viewed 3097 times

Ahh ok what sort of things can effect timing?

In the attached screen shots I have added 10 degrees to the whole standard main spark table except for the idle area.

Also attached is the spark advance historgram after playing back a log.

The knock count log is attached as well.

[delcowizzid]

woah 10 degrees LOL no lol no

[vc81]

Is it best to only go up in 1 or 2 degree increments delco?

I thought if I went up 10 then it would log knocks and I would then know which cells to adjust back down and by how much?

Do you mind sharing the process that you use?

[delcowizzid]

generally the knock sensor is turned off after 3600rpm due to engine noise causing false triggers so its useless above that.
for wide open throttle i normally add timing little by little and judge gains with traction/acceleration at take off search spark hook test on google.
you have to also factor in low load in lower gears so most spark testing WOT should be done in 1:1 ratio gear 3rd in auto 4th in T5 so as to get the maximum load on the engine or you tune in 1st and have no knock and then go full throttle on the highway and ping like all shit.
if you tune till knock and back it off your still way past where it needs to be.i do it all by feel and engine noise and on the odd ocasion gtech pro rr i generally have a driver and tune live in the passenger seat in the middle of nowhere away from cops LOL.
cruise timing your looking for lowest tps and highest map reading to sustain current rpm level a vacuam gauge is handy you want the most vacuam possible .you dont have to tune everywhere take the car for a drive and find the cells it drives in on a daily basess and tune them and the whole 100kpa colomn.
you also need to watch for vacuam at full throttle high in the rpm it can drag the spark and fueling down into the 90kpa colomn and you wonder why its not getting richer or more grunty for spark added in 100kpa when in reality your falling into the 90 kpa colomn .
with bananas youll be limited in the amount of spark it will take around 4000-4500 rpm due to the runner really getting up near sub sonic airspeed and jamming the cylinder chocka with air after there you can start raising timing again as airflow drops.

you can see in the knock table above most of the timing added is all ready being pulled back out.
dont think that no damage is being done and that the knock sensor is keeping it safe it has to start knocking for the sensr to start removing timing so it is knocking away at your main bearings allready and if it gets a plug earth strap hot and preignites holes will form in the pistons pretty quick LOL.
keep an eye on your fueling too it may change a little bit as you change timing