Hey 12secSS are you around?

[Firebirdjones]

I have some timing questions on HPtuner. I was looking at the main timing table and notice the numbers are rather low, especially at the higher rpm/load areas I only see 19 degrees set on the table.
Is there another timing table added to this main table? Maybe base timing added somewhere? I ask because 19 degrees for total timing is very low,,,most of my older cars I run anywhere from 30-36 degrees total.
I understand efficient cumbustion chambers that don't require alot of timing but 19 degrees? There has to be another table added that I don't know about. Care to explain how the table works or maybe give a little insight on what kind of total timing you or anyone has had luck with?
One other question,,,If I log the knock retard in the histograms, and I get a couple degrees here and there,,,does it work like the other histograms,,I can copy and paste over the main timing table and it will pull out timing in the appropriate areas? Thanks for any help, please enlighten me. Larry.

[foff667]

generally no...but you also need to know what cell your in as that 19* cell might be higher then you'll see G/cyl so it might not even be affecting you.

LS1 does not equal old school SBC...ls1's are far more efficient & generally require much less timing.

[foff667]

oh as far as KR...just use our copy-paste special features

only time & reading will learn you all the tricks. Check out the two get started guides in the sticky in the getting started section of hpt...they go over alot of the tricks

[Firebirdjones]

Ya I am aware the LS1 has a more efficient combustion chamber, but I am pretty sure this engine still requires more than the 19 degrees of total timing that I see in the main timing table. Other programs I have used on late 80's and early 90's vehicles always had another table that you had to remember to add to the main timing table for a total timing number.
I am guessing this is the same way?

[Firebirdjones]

Just to add, unless I am missing something, I have pretty much covered the stickies on HPtuners site and here,,,,and I haven't really seen alot that covers the timing aspect of things. Is it hidden somewhere?

[foff667]

there are adder & multiplyer tables but they are usually 0'd out in the areas you'll be in for your drive. And like I said you need to find what cells you'll be in at wot.

[Firebirdjones]

So I need to take a log with the timing histogram running and see where it's at? I guess I need to find out whats added and/or subtracted and where.
Does the Histogram show the total timing result after all the adding/subtracting is done? I mean the timing the engine is actually seeing? Or is there some math needed with the histogram to get a total timing figure?

[Firebirdjones]

You are up awfull early to be answering my questions

[Firebirdjones]

Well I checked one of my datalogs where a full throttle run was done.
At full throttle the engine is in the .76 to .80 g/cyl area in my histogram and it shows a total of 19 degrees of timing. Checking the knock retard histogram there is nothing.
I checked the timing tables, the IAT and ECT retard areas are all 0's right where the engine temp was running (178 degrees) (and the IAT was 72 degrees) so no timing is being pulled out that I know of.
Yet the main timing table shows as much as 21-22 degrees of timing around 5,000 rpms and up at .76 and .80 g/cyl. So I am missing a couple degrees somewhere.
Still this sounds very low to me. I have never seen an engine on the dyno even with the most modern cylinder head not like at least 30 degrees of total timing.
Something else that puzzles me is the "minimum TPS" table just below the main spark table. It says it's to disable the main spark table when ever this throttle position is reached (which is 1.2% on my stock tune) Why would you want to disable the main spark table? This doesn't make any sense and I can't find a good explaination of this stuff anywhere. Any insight on this? Thanks, Larry.

[12secSS]

The general like sto error on the safe side of things. Yes, most stock calibrations are set around 19 degrees of timing at 6000 while at .80g/cyl. I have founf that on most stock-to-bolt on setup, the ideal timing is between 24-29 degrees, with an AFR of 12.8. I would also log Knock Learn Factor, this will allow you to see if the ECM is using a blend of the High and Low Octane tables.

[Firebirdjones]

Thats very interesting, thank you. How do I go about logging the knock learn factor? I was wondering if that low octane table comes into play at some point? Can you stop that from happening?
I always run 94 octane in mine and don't plan to run anything less.

How quick do you have the total timing starting? I notice it doesn't peak until very high rpm like you said, but the engine barely spends any time up there. I usually set my older cars up to have total coming in as fast as 2,200 rpms and sometimes at 2,600 rpms depending on how the car reacts.
Would it be safe to say have total timing come in around 3,000 or 3,200 and go from there? Log knock retard and adjust accordingly? Can I start by possibly bumping the entire board 2 degrees and log from there? Or is that a bad idea? Sorry for all the Q's,,but that low octane table and the knock learn factor has just got me stumped. How does that work exactly while driving? Larry.

[12secSS]

To log Knock Learn Factor, just go into your scanner and insert-engine-spark retard-knock learn factor. To disable this you simply copy the high octane to the low octane, I try and steer away from this practice. Reason being is that if you get a batch of bad gas (happens) the ECM can at least tone down the timing to prevent any further knock from happening. Keeps the knock sensors from reducing your timing to what the low would have been without detonation. On all my cars (less the race car) I have tuned them to run on 87 - 91 octane. What I noticed is that the ECM will sometime command 28 degrees at WOT when I use 87. The computer is constantly using a blend of both the High and Low Octane tables, based on the knock (or lack there of) that the engine is experiencing. I try and have the timing be 28 straight across (from 2000-8000 and from .68 g/cyl to 1.20 g/cyl) if I do not have a dyno available (to extract every last once of power).

[Firebirdjones]

Awsome information I appreciate that. I was thinking the same thing about copying the high table to the low table, and figured it was probably common practice for some tuners.
Ya I am a little bit leary about that myself, but might do it temporarily until I get the high table dialed in where it needs to be, I thought it might be easier so the low table is not skewing my numbers while I log and stuff like that. Then re-enable it when I am done and see what that does.

So you have 28 degrees coming in as soon as 2,000 rpms? I might start a little lower and work my way up watching the knock retard. That is going to wake this car up tremendously, as my total isn't anything close to that stock right now. And I kinda thought this engine is a little on the lazy side, and looking at the timing table tells me alot of that lazyness is right there.

Did you find or experiment with adding anything in the lower cruise and idle tables? I thought 2-3 degrees here and there might help with part throttle response and maybe pick up a slight amount of gas mileage as well.

Thanks again this is a big help. Cheers. Larry

[12secSS]

Larry,

Yes, I found that worked best (28 @ around 2000 rpms) for my cars, while using 91 octane. And yes, as you mentioned ... start off low like around 22-24 degrees and work your way up. You may find that you will need to add more fuel to keep the AFR from leaning out too much. Trucks are notorious for having low timing, as little as -10 degrees in the part throttle areas ... yes I said negative. Bringing that table back to the positive side really wakes them up a lot!

[Firebirdjones]

Wow -10? Sheeeesh. Thats crazy. I thought 19 degrees total was low but thats unreal. I can't even imagine putting only 19 degrees in my chevelle or firebird, it would more than likely pop through the carb and die,,,lol. I will play with the timing a little when I get time and see how it affects the AFR. I am hoping to find some speed in this thing.
I noticed an improvement playing with the fuel, since all my fuel trims were in the +10 area I now have most everything -1 to -4. Throttle response has gotten slightly better, and I just checked my mileage on this tank after the fuel changes, and it's right at or a little better than it was before, after adding some fuel to it,,,so thats a good sign. I want to do another datalog (LTFT) again when the weather warms up just to double check everything, then I'll play with timing. Thanks, you've been a big help. I'll let you know how it's coming along, I may have more questions if I get stuck on something. Larry.