Spark Advance Questions - $8D Specific
Thread Starter
Cruising
Joined: Mar 2005
Posts: 12
Likes: 0
Spark Advance Questions - $8D Specific
I have done a great deal of searching in this forum and it appears that TunerCat is the choice of editor. However, I am using TunerPro RT and the Super_8dm2 ECU (both available at Mark Mansur's website). The Super_8dm2 ECU items for TunerPro and the ECU items in TunerCat seem to be very similar (descriptions), so hopefully I can get some help here.
With the Super_8dm2 ECU, there are a lot of ECU items that I have no clue what they mean. What does it control? How will a change up or down affect the operating parameters of the system/engine? Is it related to another table, or constant? How much of a change is considered normal? Trying to read a hack is all the more confusing (at least for me).
In compiling answers to my questions, I decided to organize stuff on a web page. You can see the start of my project here . This will not be an exhaustive manual, just general definitions and functions. I will use a stock AUJP bin as the baseline for discussions. It will also include screenshots of the various charts and tables. But I must be sure that what I include is accurate.
I would like to start with some of the many spark related items:
First, I must say that the following thread I found at Corvetteforum.com is probably the best SA discussion I have found to date. http://forums.corvetteforum.com/showthread.php?t=926171 Between it and the referenced links, my understanding on how the spark advance for the $8D mask is controlled is growing.
Total (Desired) Timing = Main SA Table (WYSIWYD (desire), which includes base timing) + PE SA (or HM SA), depending on throttle position & MAP readings. Knock retard subtracts timing from the Desired Timing. Idle SA is controlled by the closed throttle table (which also includes base timing), but is adjusted by RPM and MAP error tables as discussed here: http://forums.corvetteforum.com/showthread.php?t=556467 However, I still have a few unanswered spark related questions. Any help would be appreciated.
Constants:
Spark Advance Base Temp. Correction Table Bias – Does this control the “Spark Advance Temp. Correction vs. Load vs. RPM” table? The stock AUJP bin is set at 20.04* C (68* F). If so, would raising the temp. delay activation of that table?
Spark Advance Cold Disable Temp. – Does this control when the “Spark Advance Startup vs. Temp” table is no longer used to add or control timing? The stock AUJP bin is set at 44.75* C (113* F).
Spark Retard Hot Disable Temp. – Does this disable knock retard below the specified temp? The stock AUJP bin is set at 44.75* C (113* F).
Tables:
Spark Advance Startup Vs. Temp. – Do the degrees listed here add advance to Desired Timing, or override it completely? The stock AUJP bin lists between 5*-6* in this table, which leads me to believe it is added.
Spark Advance Temp. Correction vs. Load vs. RPM - Does this add to or subtract from the Desired Timing, or override it completely (similar to “SA Closed Throttle vs. RPM”)?
It seems like if you are not careful, you can make changes to your main SA table, yet not see the results because of other constants and/or tables. I am especially concerned about the effect that “Spark Advance Temp. Correction vs. Load vs. RPM” will have on my Desired Timing.
If you have the time and feel compelled to help me build this $8D manual, please E-mail me. Thanks, Ed
With the Super_8dm2 ECU, there are a lot of ECU items that I have no clue what they mean. What does it control? How will a change up or down affect the operating parameters of the system/engine? Is it related to another table, or constant? How much of a change is considered normal? Trying to read a hack is all the more confusing (at least for me).
In compiling answers to my questions, I decided to organize stuff on a web page. You can see the start of my project here . This will not be an exhaustive manual, just general definitions and functions. I will use a stock AUJP bin as the baseline for discussions. It will also include screenshots of the various charts and tables. But I must be sure that what I include is accurate.
I would like to start with some of the many spark related items:
First, I must say that the following thread I found at Corvetteforum.com is probably the best SA discussion I have found to date. http://forums.corvetteforum.com/showthread.php?t=926171 Between it and the referenced links, my understanding on how the spark advance for the $8D mask is controlled is growing.
Total (Desired) Timing = Main SA Table (WYSIWYD (desire), which includes base timing) + PE SA (or HM SA), depending on throttle position & MAP readings. Knock retard subtracts timing from the Desired Timing. Idle SA is controlled by the closed throttle table (which also includes base timing), but is adjusted by RPM and MAP error tables as discussed here: http://forums.corvetteforum.com/showthread.php?t=556467 However, I still have a few unanswered spark related questions. Any help would be appreciated.
Constants:
Spark Advance Base Temp. Correction Table Bias – Does this control the “Spark Advance Temp. Correction vs. Load vs. RPM” table? The stock AUJP bin is set at 20.04* C (68* F). If so, would raising the temp. delay activation of that table?
Spark Advance Cold Disable Temp. – Does this control when the “Spark Advance Startup vs. Temp” table is no longer used to add or control timing? The stock AUJP bin is set at 44.75* C (113* F).
Spark Retard Hot Disable Temp. – Does this disable knock retard below the specified temp? The stock AUJP bin is set at 44.75* C (113* F).
Tables:
Spark Advance Startup Vs. Temp. – Do the degrees listed here add advance to Desired Timing, or override it completely? The stock AUJP bin lists between 5*-6* in this table, which leads me to believe it is added.
Spark Advance Temp. Correction vs. Load vs. RPM - Does this add to or subtract from the Desired Timing, or override it completely (similar to “SA Closed Throttle vs. RPM”)?
It seems like if you are not careful, you can make changes to your main SA table, yet not see the results because of other constants and/or tables. I am especially concerned about the effect that “Spark Advance Temp. Correction vs. Load vs. RPM” will have on my Desired Timing.
If you have the time and feel compelled to help me build this $8D manual, please E-mail me. Thanks, Ed
Burning Brakes
Joined: May 1999
Posts: 760
Likes: 1
From: Greenwich, CT
I think I saw your site before - aren't you converting a truck from TBI to TPI?
If so, that was a very well-organized piece of HTML work. My compliments
on it.
You are right - that SA thread was beautifully written! But how do you know
it's correct?
Just so we are clear, I am not (and never will be) a certified
GM programmer, nor do I recommend using any of my information in any car
except mine.
With respect to technical writing by people that actually know something, the
'How to 3-D Table' thread was contributed by 'SuperSportX2' (Ken C).
He then went on to create his own (team) disassembly of the LS1 code - that's
the editing package sold at http://www.hptuners.com/ . He's VERY impressive
with code work; there is a discussion board at that site for the newer PCM's.
Ken left a few threads on other boards (some of which are hilarious) but
nothing much else on 8D.
Other 8D info that might be useful:
A brief narrative of fuel metering was placed here a year or so ago:
http://forums.corvetteforum.com/showthread.php?t=689344
There is some description of HEI ignition design & some DIY tuning tools on
my CF web page(s).
After that, IMHO the TGO board is your best bet for factual 8D program info.
A couple of the people there (RBob, Saturn5) have actual engineering
backgrounds; and the European guy that wrote the recent 'How to Disassemble
a Bin' seems to understand Assembly pretty well. The rest should probably
be taken with a grain of salt (or two).
As for your Q's, most of those tables or constants are ones I have not had to
use tuning a Y car. I generally don't change something unless there is a
demonstrable reason for it.
Spark Advance Temp. Correction vs. Load vs. RPM - IIRC is an adder
to the base timing tables, used mostly for engine warm-up. I couldn't improve
on GM's work, though I played around with it some.
Anything labeled 'Table Correction Bias' is usually a fixed reference
value somewhere in the code. Any change to it is typically global; they need
to be treated with great care.
For the others you should probably ask the TunerPro guys what definitions
they used.
Good luck with your project.
DrJ
If so, that was a very well-organized piece of HTML work. My compliments
on it.
You are right - that SA thread was beautifully written! But how do you know
it's correct?
Just so we are clear, I am not (and never will be) a certified GM programmer, nor do I recommend using any of my information in any car
except mine.
With respect to technical writing by people that actually know something, the
'How to 3-D Table' thread was contributed by 'SuperSportX2' (Ken C).
He then went on to create his own (team) disassembly of the LS1 code - that's
the editing package sold at http://www.hptuners.com/ . He's VERY impressive
with code work; there is a discussion board at that site for the newer PCM's.
Ken left a few threads on other boards (some of which are hilarious) but
nothing much else on 8D.
Other 8D info that might be useful:
A brief narrative of fuel metering was placed here a year or so ago:
http://forums.corvetteforum.com/showthread.php?t=689344
There is some description of HEI ignition design & some DIY tuning tools on
my CF web page(s).
After that, IMHO the TGO board is your best bet for factual 8D program info.
A couple of the people there (RBob, Saturn5) have actual engineering
backgrounds; and the European guy that wrote the recent 'How to Disassemble
a Bin' seems to understand Assembly pretty well. The rest should probably
be taken with a grain of salt (or two).
As for your Q's, most of those tables or constants are ones I have not had to
use tuning a Y car. I generally don't change something unless there is a
demonstrable reason for it.
Spark Advance Temp. Correction vs. Load vs. RPM - IIRC is an adder
to the base timing tables, used mostly for engine warm-up. I couldn't improve
on GM's work, though I played around with it some.
Anything labeled 'Table Correction Bias' is usually a fixed reference
value somewhere in the code. Any change to it is typically global; they need
to be treated with great care.
For the others you should probably ask the TunerPro guys what definitions
they used.
Good luck with your project.
DrJ
Thread Starter
Cruising
Joined: Mar 2005
Posts: 12
Likes: 0
Doctor J:
Thank you for the response and the links. I was hoping that you would respond. I had already posted these questions over at TGO, but only got one response that the main SA table is the advance you want (including base), plus PE spark or HM spark. So I feel good that my total (desired) timing statement is correct. Plus, I field verified this. I set PE to zero and verified my spark advance at WOT. It matches what I command in the main SA table for those particular RPM and load values. But the other parts I posted here did not get any response at TGO, and searches there turn up empty. Maybe I will PM RBob seeking his help.
Yes, that is my TBI to TPI Suburban conversion website . Thanks for the compliment on the site, but I actually use FrontPage 2003 and it is pretty easy to use. If you can use Microsoft Word to type a letter, you can build a professional looking website with little effort. FP 2003 is only about $100 anymore.
I like documenting my experiences on the internet because eventually someone else will benefit from it. Thanks again, Ed
Thank you for the response and the links. I was hoping that you would respond. I had already posted these questions over at TGO, but only got one response that the main SA table is the advance you want (including base), plus PE spark or HM spark. So I feel good that my total (desired) timing statement is correct. Plus, I field verified this. I set PE to zero and verified my spark advance at WOT. It matches what I command in the main SA table for those particular RPM and load values. But the other parts I posted here did not get any response at TGO, and searches there turn up empty. Maybe I will PM RBob seeking his help.
Yes, that is my TBI to TPI Suburban conversion website . Thanks for the compliment on the site, but I actually use FrontPage 2003 and it is pretty easy to use. If you can use Microsoft Word to type a letter, you can build a professional looking website with little effort. FP 2003 is only about $100 anymore.
I like documenting my experiences on the internet because eventually someone else will benefit from it. Thanks again, Ed
Instructor
Joined: Aug 2004
Posts: 108
Likes: 0
Spark Advance Base Temp. Correction Table Bias – Does this control the “Spark Advance Temp. Correction vs. Load vs. RPM” table? The stock AUJP bin is set at 20.04* C (68* F). If so, would raising the temp. delay activation of that table?
Spark Advance Cold Disable Temp. – Does this control when the “Spark Advance Startup vs. Temp” table is no longer used to add or control timing? The stock AUJP bin is set at 44.75* C (113* F).
Spark Advance Startup Vs. Temp. – Do the degrees listed here add advance to Desired Timing, or override it completely? The stock AUJP bin lists between 5*-6* in this table, which leads me to believe it is added.
Spark Retard Hot Disable Temp. – Does this disable knock retard below the specified temp? The stock AUJP bin is set at 44.75* C (113* F).
May I ask you a question? The ECU file you are using, have you had a closer look at it? I compared my ECU file with the anth_hac and the datastream for my L98, I cannot say they agree. Perhaps you found a better one?
