Looking for tunercat help, spark map

[JoeliusZ28]

Im just going to copy a thread i posted on another board that hasnt gotten any replies.


I am new to tuning and I am taking one step at a time setting up the tune for my new engine. (I am ademately trying to learn this stuff).

Im currently using datamaster to log, and tunercat for the tuning.

To analyze my log data, I exported a CSV file to microsoft excel and put manifold pressure, RPM, and spark retard into a pivot table. The first thing i noticed is that datamaster logs in a MUCH higher data resolution than the spark map in tunercat. For my first tune I kind of eyeballed where there was spark retard and actually pulled timing from the stock tune (i have an advanced cam) and this seemed to help quite a bit. However, i can still tell the spark map is off in many places by just driving the car, and I am definitely not one to be happy with an eyeball tune after seeing what my buddy has been able to accomplish with HPTuners. When I try to put the Excel pivot table into the same resolution as the [tunercat] spark map, it seems as though excel just throws out the in-between data instead of averaging it. (although i havent really figured out what it does). If that is what is happening though, obviously that makes the log much more statistically insignificant for an accurate adjustment.

The other thing i noticed is that I log a lot of .1, .2, or .3 degrees of spark retard, but the spark map can only be adjusted in increments of .5.

Anyway, im really just looking for some tips here. It seems like it would be a straight forward process if I could get the software to do what I want, however I am always open to learning new tuning theories.

Any input/advise is appreciated!!!:gunsmilie:

[MEAN LT1]

I hear ya man. I didnt see it in your post but when you were taking spark out did you see a difference in the amount of retard you were seeing?. My car saw alot of faulse knock when I hooked it up to datamaster and pulling timing in the rpm vs map range wasnt helping. What im trying to basically say is do know for a fact that your knock is real?.

[JoeliusZ28]

Ive noticed that same phenomenon yea. I have the LT4 KM so its not the most sensitive as it is... but there are areas I can pull timing and it doesnt seem to go away.

Im trying to figure out an alternative way to calculate the proper spark right now - I honestly dont think using logs and tunercat is the answer right now because apparently no one knows how to do it. So many people just get a mail order instead of actually figuring it out.

All I know is that my spark is still WAY off, because the engine has a shake/vibration, and there other areas it seems spot on.

[Tony Shepherd]

Even though you see .1 or .2 retard in Datamaster that is just the sensitivity of the knock sensor. In TunerCats you can only adjust timing by .5 degree minimum intervals which is fine. .5 degree and down knock retard is harmless so if you see that I would not worry about it. Adjusting .5 down in timing may help it and that is all you will need. Also notice if you set the timing in TC at say 35 degrees at 90-100 kpa at 5000 rpms you will not see the same number in Datamaster at those parameters. Datamaster might show 37 degrees when you entered 35 in the tune. I see that all the time.

[MEAN LT1]

Also notice if you set the timing in TC at say 35 degrees at 90-100 kpa at 5000 rpms you will not see the same number in Datamaster at those parameters. Datamaster might show 37 degrees when you entered 35 in the tune. I see that all the time.

Agreed. I get that ALL the time. I have my timing set at 38 degrees between 95-100kpa and im always showing 40degrees.

[JoeliusZ28]

Even though you see .1 or .2 retard in Datamaster that is just the sensitivity of the knock sensor. In TunerCats you can only adjust timing by .5 degree minimum intervals which is fine. .5 degree and down knock retard is harmless so if you see that I would not worry about it. Adjusting .5 down in timing may help it and that is all you will need. Also notice if you set the timing in TC at say 35 degrees at 90-100 kpa at 5000 rpms you will not see the same number in Datamaster at those parameters. Datamaster might show 37 degrees when you entered 35 in the tune. I see that all the time.
Thanks tony... so lets say I have 0s across the board with the exception of a few .1s and .2s.... should I try advancing the whole thing and then pulling timing until get approximately .1-.2 knock? (Is OBD1 capable of correcting in the other direction?)

I just want to do this to get it close and from there Ill look at the MAP pressure to fine tune it.

All I know is my timing is way off right now because when I do the quick throttle lift between the gears [at WOT] the car hesitates while it figures out how much to correct again. It also shakes more than it should at cruising RPM.

[Tony Shepherd]

Thanks tony... so lets say I have 0s across the board with the exception of a few .1s and .2s.... should I try advancing the whole thing and then pulling timing until get approximately .1-.2 knock? (Is OBD1 capable of correcting in the other direction?)
.


No no. That is not what you want to do. The idea is to get the most power with the correct timing without knock. But if you have .1 or .3...etc it is fine. Do not try to raise timing up to that point of having slight knock because more than likely it will not be gaining power with the raised timing anyways. Also it will not go in the other direction. It will stay at the preset timing until it senses knock then it pulls out appropriately.

[Twisted Z]

While you are tuning do this.

Zero out ALL the low Octain tables. You will find a new car to tune on. the LTx PCM works different then the LSx system in that one you get a hard knock it kicks into low octain and trows you for a huge curve. This is also why Hooker headers used to be such a huge problem. They 'rang' at a freq that the Knock sensor would set off Low Oct. mode ;)

Try it the results might suprise you :D

BTW the reason it is such a PITA is it is not a real table it starts running a multiplier of the main Spark tables

[MEAN LT1]

While you are tuning do this.

Zero out ALL the low Octain tables. You will find a new car to tune on. the LTx PCM works different then the LSx system in that one you get a hard knock it kicks into low octain and trows you for a huge curve. This is also why Hooker headers used to be such a huge problem. They 'rang' at a freq that the Knock sensor would set off Low Oct. mode ;)

Try it the results might suprise you :D

BTW the reason it is such a PITA is it is not a real table it starts running a multiplier of the main Spark tables

I never thought about doing this. I figured if I ever accedently put 89 or bad gas that table would be a safety net of sorts.

[JoeliusZ28]

While you are tuning do this.

Zero out ALL the low Octain tables. You will find a new car to tune on. the LTx PCM works different then the LSx system in that one you get a hard knock it kicks into low octain and trows you for a huge curve. This is also why Hooker headers used to be such a huge problem. They 'rang' at a freq that the Knock sensor would set off Low Oct. mode ;)

Try it the results might suprise you :D

BTW the reason it is such a PITA is it is not a real table it starts running a multiplier of the main Spark tables
wow i dont think you realize how much grief that saves me. I have been making adjustments at the assumption there was no multiplier like that. That makes perfect sense and its things like that you only learn with experience!

I hope i get a chance to try some of this stuff before the snow flies.