: What is Tuning? By Definition



AJxtcman
12-16-08, 02:37 PM
What is tuning a PCM?

In my opinion it is recalibrating a .bin file or a calibration file.

This could be a simple as segment swapping or total control over all the paramaters.

Not 1 single aftermarket tuning software company allows you to have control over all the parameters.

Example of Basis Tuning

different injector size
Aftermarket MAF
Cam swaps
gear ratio changes
DTC delete
Adjusting Fuel trims to 0
Adjusting timing to a preset limit
Adjusting Shift points
Adjusting TCC engagement


Examples of more Advanced Tuning

Adjusting the AFR and fuel Trims for max performance
Adjusting Timing for max performance
Adjusting shift points for max performance
Adjusting Trans Line Pressure
Adjusting the EGR parameters
Adjusting Knock Retard and Sensitivity


I know you can do a ton more, but lets see what you think.

AJxtcman
12-16-08, 02:53 PM
This is HP tuners list of GM Parameters

GM Parameters (http://www.hptuners.com/help/vcm_editor_parameters_gm.htm)

AJxtcman
12-16-08, 03:12 PM
LS1-Edit User Guide (http://www.omnituner.com/DesktopModules/YetAnotherForumDotNet/resource.ashx?a=77)

N0DIH
12-16-08, 03:25 PM
For a great many years now, Tuning, either via a speed shop or a tuner, or racer, would change the way his/her vehicle would operate, differently from what the manufacturer designed. Either to improve on the conservative approach that say GM, etc set the car/truck up originally.

For Example:
My 1980 Turbo T/A
I added a shift kit (comp mode, B&M) to improve the THM350.
I changed the ignition timing from 24 degrees MAX timing to something more suitable
I added HD Rancho GTIII Sway Bars
I remove the turbo wastegate cruise mode bypass to speedup boost
I remove the coolant under the turbo plenum
I did some Q-Jet mods
I ran 14.21@97.3 mph.... Up from an advertised 16.0-17.0 by the major mags.... (probably was close)
And so on.... I tuned it. I read up in a LOT of magazines things that would help and did them. I had Midwest 4WD nearby to buy my goodies from (Home of Bigfoot...). Ask MANY of 5.0L Mustangs in the mid to late 80's, they HATED me! 0-40 we were tied, 40-100 they saw taillights.... I was a dead match for a 86 Vette 55-135 mph.... It wasn't bad for a 4030 lb car with 3.08's....

In all honesty it doesn't matter HOW you change it, either hard parts, software, combo of the 2, changing it to something that better matches the car/truck's needs or the drivers needs, is tuning. At least IMNASHO... (In My Not Always So Humble Opinion)

If you knew the hot rod industry, for some, especially the big names in it, as as crooked as the Illinois Governor's charges...... The catch is, they are often as slippery.... I know some, it is a MESSED UP industry when they get into big business....

Submariner409
12-16-08, 03:55 PM
"In tune" or the verb "tune" implies that something is restored to its original state or frequency.

"Tune", as now applied to automotive engine systems and sometimes suspension, is a bastardized verb meaning "to alter original operating specification(s) in order to gain (maybe......) enhanced performance".

N0DIH
12-16-08, 04:58 PM
Or to correct for changes in the engine. Example: Cam change, adding base timing to the calibration.

Calibration is probably the best term to use. If something is calibrated, it is set to operate at a certain parameter. So changing the calibration changes the parameters...

So for a cam swap, the cyl pressure in the lower rpm region is lower and must be restored (compression or timing), to restore the throttle response and performance.

AJxtcman
12-16-08, 05:15 PM
In my opinion TunerCat has the best software and support. I would say EFILive is #2

If you want something added that you heard about TC will add it with no problems. TC will build a custom one on one VDF for you. With TC you could have 100% control.

AJxtcman
12-16-08, 08:10 PM
In my opinion TunerCat has the best software and support. I would say EFILive is #2

If you want something added that you heard about TC will add it with no problems. TC will build a custom one on one VDF for you. With TC you could have 100% control.

I got pulled away from this post.

What do you think is in a Hand held tuner like Hypertech or a Superchips?

97EldoCoupe
12-16-08, 10:38 PM
AJ I'm no expert like you are in this field but I would say all those tuners consist of is something that communicates with the vehicles PCM and changes some values in the bin file in the PCM to that of which the user chooses, user input being from a keypad and a GUI to display info to the user.

Raze
12-17-08, 10:58 PM
AJ I have a new product for you to look at since it's been used on a 2003 OEM PCM N*, auto trans that was swapped into a replica 1948 Tucker: Power Perfect SMT6 or the NEW SMT8. You can contact Bob Ida of Ida Automotive since he tuned the twin turbo'd N* w/an SMT6 on an OEM PCM/wiring harness/sensors. It's a piggyback but for the price it seems fair, $470 for an SMT8, cheaper for the 6, and for $70-100 they'll give you a wiring diagram if you need it (I wouldn't but for people who don't know what someting like a MAF sensor is it'd be helpful) and they have a tuning shop in NJ and have tuned very a many Ford GTs, and other 'big dollar' cars. I found the info very interesting...

AJxtcman
01-22-09, 08:22 PM
:want: Bump because i am tiered of seeing all the people whining about head gaskets.:rant2:

I have something to post also :yawn:

AJxtcman
01-23-09, 08:21 AM
This is a link to HPTuners Help Reference guide
VCM Suite Online Help (http://www.hptuners.com/help/index.html?page=introduction_customersupport.htm)

This is the GM Parameters that you can change.
Parameters - GM (http://www.hptuners.com/help/vcm_editor_parameters_gm.htm)

This is the How To section
Tuning How To Section (http://www.hptuners.com/help/vcm_editor_tuning_how_to.htm)

In the Tuning How to you will find Basic and Advanced

Basics

Rear Gear/Tire Ratio (http://www.hptuners.com/help/vcm_editor_tuning_how_to_basics_gear_tire.htm)

Shift Points (http://www.hptuners.com/help/vcm_editor_tuning_how_to_basics_shift_points.htm)

Timing Advance (http://www.hptuners.com/help/vcm_editor_tuning_how_to_basics_advance.htm)

Air/Fuel Ratio (http://www.hptuners.com/help/vcm_editor_tuning_how_to_basics_afr.htm)

Injectors (http://www.hptuners.com/help/vcm_editor_tuning_how_to_basics_injectors.htm)

RPM Limiters (http://www.hptuners.com/help/vcm_editor_tuning_how_to_basics_rpm_limiters.htm)

AJxtcman
01-23-09, 08:30 AM
Just so we all understand! :rant2:

I can change the following on a Northstar PCM as described by HPTuners Definitions

Gear Ratio
Shift Points
Air/Fuel Ratio
RPM Limiters
Timing Advance


The Timing Advance I need to spend more time on. I think I need to look for a 3rd table. I never thought about a 3rd table until another member posted some info on Octane Level Displayed
Take a look at this
GM > Engine > Spark Control > Spark Advance (http://www.hptuners.com/help/vcm_editor_parameters_gm_eng_spark_advance.htm)

AJxtcman
01-24-09, 12:22 PM
Just so we all understand! :rant2:

I can change the following on a Northstar PCM as described by HPTuners Definitions

Gear Ratio
Shift Points
Air/Fuel Ratio
RPM Limiters
Timing Advance


The Timing Advance I need to spend more time on. I think I need to look for a 3rd table. I never thought about a 3rd table until another member posted some info on Octane Level Displayed
Take a look at this
GM > Engine > Spark Control > Spark Advance (http://www.hptuners.com/help/vcm_editor_parameters_gm_eng_spark_advance.htm)


What if I skewed the MAF reading? Would it do all the above?

I have not done that! REPEAT I have not done that!!

I just want you to think about Tuning and what 1 adjustment could do!!!!!!!!!!!!!!!!!!!!

I have seen this done by big name tuners. cough

N0DIH
01-25-09, 01:06 AM
It is in the LS1 and 3100/3400/3800 too, Adaptive Spark Multiplier. It is in %, but it is a % between the low octane and high octane table. Contrary to most belief's the high/low octane table makes up a 3D map, and the Adaptive Spark Multiplier makes up a new "3D map", as it tries to keep towards the high octane "upper limit" and the low octane is the "lower limit" of this virtual adaptive table.

I think Cadillac did it differently, a Calculated Octane Number IIRC. Then probably fed the ASM or it was the ASM.

Is that what you were talking about?



Just so we all understand! :rant2:

I can change the following on a Northstar PCM as described by HPTuners Definitions

Gear Ratio
Shift Points
Air/Fuel Ratio
RPM Limiters
Timing Advance


The Timing Advance I need to spend more time on. I think I need to look for a 3rd table. I never thought about a 3rd table until another member posted some info on Octane Level Displayed
Take a look at this
GM > Engine > Spark Control > Spark Advance (http://www.hptuners.com/help/vcm_editor_parameters_gm_eng_spark_advance.htm)

AJxtcman
01-25-09, 10:19 AM
It is in the LS1 and 3100/3400/3800 too, Adaptive Spark Multiplier. It is in %, but it is a % between the low octane and high octane table. Contrary to most belief's the high/low octane table makes up a 3D map, and the Adaptive Spark Multiplier makes up a new "3D map", as it tries to keep towards the high octane "upper limit" and the low octane is the "lower limit" of this virtual adaptive table.

I think Cadillac did it differently, a Calculated Octane Number IIRC. Then probably fed the ASM or it was the ASM.

Is that what you were talking about?

I think someone told me about these 3D maps when they had some knock on a 3800 SC :hmm:

Maybe I should think about posting that map.

Submariner409
01-25-09, 12:40 PM
AJ, For a 2002 STS VIN 9 F55 PCM are you able to add 3 - 5 degrees of basic timing advance and remove the 130 speed limiter ??

N0DIH
01-25-09, 03:40 PM
wonder who messes with them v6's? Most are wrong wheel drive....:bouncy:


I think someone told me about these 3D maps when they had some knock on a 3800 SC :hmm:

Maybe I should think about posting that map.

AJxtcman
01-25-09, 10:42 PM
AJ, For a 2002 STS VIN 9 F55 PCM are you able to add 3 - 5 degrees of basic timing advance and remove the 130 speed limiter ??

The spark has been an issue with me currently.

When I change spark in the table it doesn't produce the same amount of effect. OK I change the spark in the low octane and the same thing happens.

Can you tell me what TPS, MAP, MAF, RPM you would like it done at?
I don't need all of them, but what RPM and Load are you looking at?

This is from HPTuners web site

Main Spark Tables
The VCM constantly looks up both High Octane and Low Octane spark tables and interpolates a value between the two tables based on the current Knock Learn factor. If the engine has been operating for a moderate time without any Knock Retard then Knock Learn is zero and the interpolation favors the High Octane table, if Knock has been detected then the interpolation will move towards the Low Octane table. During MAF failure the Knock Learn is set to maximum and the Low Octane table is used (HP Tuners speed density enhancements allow both spark tables to function).


Note: Excessive spark advance will cause knock (detonation, pinging) and lead to severe engine damage. Do NOT rely on knock sensors as the only source of detecting knock during tuning.




High Octane: This is the High Octane spark advance versus RPM and Cylinder Airmass.
Low Octane: This is the Low Octane spark advance versus RPM and Cylinder Airmass.



High Octane vs. MAP vs. RPM: This is the High Octane spark advance versus MAP and RPM (some I4/5/6 vehicles).
Low Octane vs. MAP vs. RPM: This is the Low Octane spark advance versus MAP and RPM (some I4/5/6 vehicles).
High Octane vs. MAP vs. RPM (Alcohol): This is the High Octane spark advance versus MAP and RPM when running alcohol fuel (some I4/5/6 vehicles).
Low Octane vs. MAP vs. RPM (Alcohol): This is the Low Octane spark advance versus MAP and RPM when running alcohol fuel (some I4/5/6 vehicles).



High Octane PE Spark vs. MAP vs. RPM: This is the High Octane spark advance used during PE mode versus MAP and RPM (some I4/5/6 vehicles).
Low Octane PE Spark vs. MAP vs. RPM: This is the Low Octane spark advance used during PE mode versus MAP and RPM (some I4/5/6 vehicles).
High Octane PE Spark vs. MAP vs. RPM (Alcohol): This is the High Octane spark advance used during PE mode versus MAP and RPM when running alcohol fuel (some I4/5/6 vehicles).
Low Octane PE Spark vs. MAP vs. RPM (Alcohol): This is the Low Octane spark advance used during PE mode versus MAP and RPM when running alcohol fuel (some I4/5/6 vehicles).



Main Spark - Intake Min, Exhaust Min: Main Spark when intake camshaft is at minimum and exhaust camshaft is at minimum.
Main Spark - Intake Min, Exhaust Max: Main Spark when intake camshaft is at minimum and exhaust camshaft is at maximum.
Main Spark - Intake Max, Exhaust Min: Main Spark when intake camshaft is at maximum and exhaust camshaft is at minimum.
Main Spark - Intake Max, Exhaust Max: Main Spark when intake camshaft is at maximum and exhaust camshaft is at maximum.



Cranking Spark: This table is used to define the spark during engine cranking.

Main Spark Table Selects
If either of these TPS or MPH values is exceeded the VCM will select the Main Spark tables, otherwise the Base Spark tables are used. The value minus the hysteresis is required to revert back to the Base table from the Main tables.

TPS: This value is the Throttle Position required to disable the Main Spark tables
TPS Hysteresis: This value is added to the value above as the threshold to activate Main Spark table in relation to TPS.
Speed: This value is the Speed required to disable the Main Spark tables
Speed Hysteresis: This value is added to the value above as the threshold to activate Main Spark table in relation to speed.

Base Spark Tables


Base Spark vs. Airflow vs. RPM Closed Throttle, In Drive: This is the base spark used predominantly at idle with selector in gear.
Base Spark vs. Airflow vs. RPM Closed Throttle, In Park: This is the base spark used predominantly at idle with selector in Park or Neutral.

Idle Spark Advance


Base: This is the base spark used predominantly at idle.
Coastdown: This is the base spark used predominantly while the vehicle in in coastdown.
Idle Spark Adder (P/N): This adds to the current idle spark while in Park/Neutral.
Idle Spark Adder (In Gear): This adds to the current idle spark while in Gear.
Idle Spark Mult vs. Baro: This modifies the idle spark in relation to barometic pressure.



Base vs. MAP: This is the base spark used predominantly at idle (some I4/5/6 vehicles).
Base vs. MAP (Alcohol): This is the base spark used predominantly at idle when running alcohol fuel (some I4/5/6 vehicles).

Spark Correction
The VCM incorporates a number of corrections to the spark advance depending on current engine operating conditions.

AFR Spark Advance Correction - Add: This table is used to modify spark advance based on the current commanded AFR value (Fuel/Air multiplier). It is used during lean cruise mode and adds to the current spark advance.
AFR Spark Advance Correction - Mult: The multiplier table is used to proportionally enable or disable this feature in relation to MAP.
AFR Spark Advance Correction - Gas: These values are added to the spark advance in relation to EQ Ratio. It is used in the various enrichments modes (PE, COT, etc.)
AFR Spark Advance Correction - Alcohol: These values are added to the spark advance in relation to EQ Ratio. It is used in the various enrichments modes (PE, COT, etc.)
AFR Spark Advance Mult vs. Fuel Composition: The multiplier table is used to modify the spark value based on fuel composition (flex fuel only).
AFR Spark Advance Correction Mult vs. MAP: The multiplier table is used to proportionally enable or disable this feature in relation to MAP.



IAT Spark Advance Correction - Add (Base): This table is used to modify spark advance based on inlet air temperature. It adds to the current spark advance.
IAT Spark Advance Correction - Mult: The multiplier is used to proportionally enable or disable this feature.
IAT Spark Advance Correction - Mult 2: The multiplier is used to proportionally enable or disable this feature.



ECT Spark Advance Correction - Add (Base): This table is used to modify spark advance based on engine coolant temperature. It adds to the current spark advance.
ECT Spark Advance Correction - Mult: The multiplier is used to proportionally enable or disable this feature.



Lightoff Spark (Normal): Catalytic converter lightoff (warmup) spark table. Used to modify timing during startup to heat the cats faster.
Lightoff Spark (Coast): Catalytic converter lightoff (warmup) spark table. Used to modify timing during startup to heat the cats faster during coastdown.
Lightoff Spark Idle (P/N): Catalytic converter lightoff (warmup) spark table. Used to modify timing during startup to heat the cats faster during idle in Park/Neutral.
Lightoff Spark Idle (Gear): Catalytic converter lightoff (warmup) spark table. Used to modify timing during startup to heat the cats faster during idle in Gear.



Launch Spark: Base launch spark table. Used to modify timing during cold start takeoffs.



Piston Slap Spark: This table is used to modify spark advance to reduce piston slap (noise) during warmup.



Startup Spark Correction: During the first 80 seconds of engine operation the VCM has the ability to modify the spark advance based on cylinder air and time. Generally this is used to assist in cold start low speed drivability. This value adds to the spark advance.
Startup Spark Correction Mult vs. Startup ECT: The Multiplier table is used to enable and disable startup spark correction based on coolant temperature it is a proportional value between 0 and 1.



EGR Spark Advance Correction - Add: This table is used to modify spark advance based on EGR operating conditions. It adds to the current spark advance.



Startup Flare Control: This table is used to adjust timing to attempt to control RPM flaring during startup.
Startup Flare Control - Mult: The multiplier table is used to proportionally enable or disable this feature in relation to ECT.




Idle Adaptive Spark Control

Overspeed: Amount of spark adjustment in response to an idle overspeed condition.
Underspeed: Amount of spark adjustment in response to an idle underspeed condition.



Overspeed (P/N): Amount of spark adjustment in response to an idle overspeed condition in Park/Neutral.
Overspeed (Gear): Amount of spark adjustment in response to an idle overspeed condition in Gear.
Overspeed (Coast): Amount of spark adjustment in response to an idle overspeed condition in coastdown.
Underspeed (P/N): Amount of spark adjustment in response to an idle underspeed condition in Park/Neutral.
Underspeed (Gear): Amount of spark adjustment in response to an idle underspeed condition in Gear.
Underspeed (Coast): Amount of spark adjustment in response to an idle underspeed condition in coastdown.

Mean Best Timing

Max Torque Timing vs. RPM vs. Cyl Air: Theoretical spark advance that delivers maximum torque. PCM torque calculation routines reference this table when estimating current engine torque output relative to theoretical maximum. We do not recommend modifying this table.

AC Torque Spark

AC Bump Torque Spark: Enables/Disables spark adjustment when AC cycle on/off.
AC Bump Torque Idle Spark: Enables/Disables spark adjustment when AC cycle on/off at idle if AC Bump Torque Spark is enabled.

Ur7x
01-26-09, 12:34 AM
AJ, For a 2002 STS VIN 9 F55 PCM are you able to add 3 - 5 degrees of basic timing advance and remove the 130 speed limiter ??


The spark has been an issue with me currently.

When I change spark in the table it doesn't produce the same amount of effect. OK I change the spark in the low octane and the same thing happens.



The short answer on the spark curve is that he can't.... and even if he could he has no idea if it will make things better.

Let me explain. In the early days of distributors (pre 1980) the distributor used 2 inputs to determine the advance... RPM and Load (engine vacuum) it used those two things to mechanically determine the advance...

Then around 1980 along came the CCC system, and it replaced the vacuum canister with a MAP sensor but basically it did the same thing and this resulted in the "3D spark map" that AJ was wondering about 3 or 4 posts ago... This was the "hey day" for "chipers" since you could make a change confident that you know what you were going to get and it was easy to test your results...

The equation was simple and it was easy to measure the results...

Then in 1985 (or so) they started to add knock sensors and speed limiters and tranny shift delay algorithms and the 3D chart became a mind blowing 9D and beyond chart. To the point were you had almost no idea what a change to the main spark table might do... Often, especially if the engine was on the edge of detonation, it would have NO effect AT ALL. Or worse a change that should add 5 or six horse power would run into some other "control variable" and the car would run a 10th slower in the quarter (and we have never seen that ;) )

Moving ahead with the advent of OBDII things only got worse... As AJ's quote from HP tuners shows now there are DOZENS and DOZENS of inputs that the PCM considers when it sets timing and fuel delivery.

There is a speed table, a knock attack table, a knock retard table, a highway "constant speed" table, a egr table, a cold start table, a hot start table, a overheat table, a traction control table, a transmission protection factor, a max spark table, min spark table, bla bla bla.. There are dozens these chips started out as 1Kilo Byte babies and now they are Mega Byte monsters.

A good place to start is with this:
http://www.geocities.com/ecmguy.geo/bruce/prog_101.html

And that was for a PCM from 19 years AGO... We have come along way from there.

The PCM takes inputs from all over the car and engine, adds some, subtracts some, compares some, truncates a few and based on over a dozen or so inputs it determines fuel requirements and spark advance.

To tune a PCM you need to know and understand two things
1) the location of each and every table, AND just as important,
2) the logic the PCM uses to manipulate those tables to calculate the final spark advance.

If you don't know both of those...and I mean REALLY know them...
Then you are basically forced to make a change, run the car, see if the change made things better and the move on from there... Of course this becomes more and more difficult as the change could (and usually does) have undesirable side effects.... Or as we have seen has no change what so ever.

If you are unwilling to do the enormous effort of test, run, repeat, repeat, repeat and repeat some more... Then you are forced to just take a stock PCM that you know works the best and swap that in...

Which is not at all bad... lots of tuners do that... You take a stock tune from the best motor the they made in your family of motors and you build a motor like that one (custom tunes are useless without custom engine work) and then you use that tune... GM created a ton of excitement for example with the ZZ4 chips the offered with the HO350 swap kit they sold for 82-86 Camaro's... Lots of guys used that tune to swap 350's into EVERYTHING. and have the motor run as well as the ZZ4 in the Camaro swap... Of course running the ZZ4 Chip in a LG4 305 Camaro had a car that ran WAY too rich and produced less power, bad millage and even worse emissions.

What is tuning?
That would be building a custom PCM that matches the CUSTOM ENGINE MODIFICATIONS that you have done...
If your car is stock, it will work best with a stock PCM.

AJxtcman
01-26-09, 08:10 AM
That is not what this thread is about.

Submariner409
01-26-09, 11:33 AM
Actually, Ur7x' reply is exactly what this thread is about. TUNING. I knew full well before I posted my "basic timing advance" question that there is no way on earth to perform a PCM tweak similar to twisting a distributor 2 degrees + or -. I shudder to think how many basic Delco points and HEI distributors I have assembled over the years.....hundreds. Fun and games, and with a handful of springs and weights and an old Sun machine you can dial in any advance curve you want. Adjustable vacuum cans were another luxury. Pertronix and Mallory were another yet...

Not so in our Northstar 2000 - 2004 world. Watching the PCM advance/retard performance while driving bears no relation to "the old days". If I think I have a handle on a particular load/advance reading, that observation is impossible to duplicate under what should be the same conditions. It's as HPT and Ur7x state: There are so many variables in the stew pot that meaningful ignition tuning is damn near impossible in the 2000 - 2004 series of GM PCM's. The ultimate trick would be to leave the existing PCM to run the body and transmission and adapt a stand-alone ICM to the engine.

AJxtcman
01-26-09, 01:30 PM
Sub I typed out a long post and then Deleted it. I was going to post it in the Tuning thread, but decided not to.

This thread is ment to clear up what Tuning IS!
I didn't want to cluter it up. OK?

I will post over in the Tuning thread in a few days on your question.



Actually, Ur7x' reply is exactly what this thread is about. TUNING. I knew full well before I posted my "basic timing advance" question that there is no way on earth to perform a PCM tweak similar to twisting a distributor 2 degrees + or -. I shudder to think how many basic Delco points and HEI distributors I have assembled over the years.....hundreds. Fun and games, and with a handful of springs and weights and an old Sun machine you can dial in any advance curve you want. Adjustable vacuum cans were another luxury. Pertronix and Mallory were another yet...

Not so in our Northstar 2000 - 2004 world. Watching the PCM advance/retard performance while driving bears no relation to "the old days". If I think I have a handle on a particular load/advance reading, that observation is impossible to duplicate under what should be the same conditions. It's as HPT and Ur7x state: There are so many variables in the stew pot that meaningful ignition tuning is damn near impossible in the 2000 - 2004 series of GM PCM's. The ultimate trick would be to leave the existing PCM to run the body and transmission and adapt a stand-alone ICM to the engine.

Ur7x
01-26-09, 02:14 PM
This thread is ment to clear up what Tuning IS!
I didn't want to cluter it up. OK?


Let me repost the last three lines of my cluter...


What is tuning?
That would be building a custom PCM that matches the CUSTOM ENGINE MODIFICATIONS that you have done...
If your car is stock, it will work best with a stock PCM.

I could not make it more clear.

BTW the cluter nicely documents how hard this is and why most "tuned chips" on stock motors yeild so-so results...

There is no magic bullet, there is no quick fix..

Pete1996
08-21-09, 10:04 PM
Quote:Originally Posted by Ur7x
"What is tuning?
That would be building a custom PCM that matches the CUSTOM ENGINE MODIFICATIONS that you have done...
If your car is stock, it will work best with a stock PCM.

I could not make it more clear.

BTW the cluter nicely documents how hard this is and why most "tuned chips" on stock motors yeild so-so results...

There is no magic bullet, there is no quick fix.."
End Quote: by Ur7x

=======================================
I'm new here, so first let me mention that I am an analog/digital/systems hardware engineer with an emphasis on computers, and communications systems. I'm also mechanically inclined and have worked on cars since I was a kid.

Let me draw an analogy. In electronics when we do a chip design we build in margin so that nearly every chip off the line that does not have a gross defect works in the system. We call it PVT margin for process, voltage, and temperature. The chemical processes used to fabricate chips are not exact, they vary causing speed, voltage threshold shifts etc., the supply voltage is not exact, nothing is, so we allow for 5% variation, 10% often for Military designs. Temperature - depending on ambient, and how hard the system is working we have a very wide range of junction temperature - speed and thresholds are also dependent on temperature. I take it you all have heard of overclocking PCs? These are the main reasons why it works - not that I recommend it for the average user.

I would expect the stock PCM program to be _very_ conservative with a lot of margin, when properly designed - meaning bug free, to allow for aging of the engine parts, poor maintenance habits, etc. Many here seem to want to take old cars and get more performance, unfortunately - I think we are loosing margin in an old engine, but there is probably room for significant gains in a newer engine. I would think that the top end of the Norhstar could easily do 7500 RPM when new, without vavle float and probably with good breathing. But I doubt if the average Cadillac customer wants to hear their motor reving to 7500 RPM. It currently rev limits, might not have the fuel supply or timing to provide increased horsepower up to those revs, but this would be the simple way to get significantly more power from the stock motor. It would not be recommended, obviously for an old motor with weak valve springs and who knows what else that is near end of life.

Obviously, we want some margin on the rev limit, does anyone know where the valves float, or lifters pump up, on a stock new Northstar? Anyone know the design margin on the rev limit for the Northstar? How about the bottom end, at what RPM does it blow up? You want to look at linear piston velocity versus RPM. Is there a technical paper on the Northstar design with some of these parameters?

I would think that pushing the rev limit up by say 500 RPM for a mild performance tune, and 1000 for a hot tune would be doable. New fuel, and timing curves would be required. However, as has been stated extensive testing would be required to be sure that everything was right. I would probably limit these higher states of tune to kick in only under optimum conditions; this is an advantage of having PCM control - you don't have to provide the gain when the car is misused and so you can fall back on the factory program. If I was an independent doing such tuning, I'd say use it at your own risk.

More RPM is the way to power with an engine that breathes and does not have the capacity like a 6+ liter motor.

Pete

Pete1996
08-21-09, 10:17 PM
Actually, Ur7x' reply is exactly what this thread is about. TUNING. I knew full well before I posted my "basic timing advance" question that there is no way on earth to perform a PCM tweak similar to twisting a distributor 2 degrees + or -. I shudder to think how many basic Delco points and HEI distributors I have assembled over the years.....hundreds. Fun and games, and with a handful of springs and weights and an old Sun machine you can dial in any advance curve you want. Adjustable vacuum cans were another luxury. Pertronix and Mallory were another yet...

Not so in our Northstar 2000 - 2004 world. Watching the PCM advance/retard performance while driving bears no relation to "the old days". If I think I have a handle on a particular load/advance reading, that observation is impossible to duplicate under what should be the same conditions. It's as HPT and Ur7x state: There are so many variables in the stew pot that meaningful ignition tuning is damn near impossible in the 2000 - 2004 series of GM PCM's. The ultimate trick would be to leave the existing PCM to run the body and transmission and adapt a stand-alone ICM to the engine.


The real question is why would you want this? Let's assume you want it for a primative old style racing engine. You'd take the base normal operating table and copy it into all the others after adding your advance. Then no matter which table the adaptive control tried to switch to, you'd get an emulation of your old dumb distributor with a single curve. You asked for it - that is one way to get it, not exactly sure why you would want it. It demonstrates the power of table driven software, consider the alternative, a single base table with algorithmic adaptation, you'd have to understand all the algorithms and their interactions. We have learned that often the designer can't keep track of the complexity, and what if the person leaves the project? Tables are easy, what you get is what you put in the table.

Another solution to your question, make the crankshaft position sensor lie (alter the cal table), who knows what else that would screw up, lol!

Pete

I don't know why several here seem to assume that it is impossible for this to be done. Yes, obviously it is not easy.
Yes there might be bugs, or mistakes, but AJxtcman is getting there and making progress so let the man do his work.

Pete1996
08-21-09, 11:52 PM
Found the Northstar Overview for the second generation engine and noticed that the valves have some sort of electronic control for the lifters - have no idea how that might impact the rev limit. The paper does not discuss margin in the design.

Pete

Submariner409
08-30-09, 11:29 AM
Pete, My post - your quote in #26 - was rhetorically aimed specifically at those who believe there is some magical way to tune a late Northstar FWD PCM for significant gains in power and "speed".

How many times have you answered a question in here or another forum, an answer based on experience and study, and been told "You're full of crap ! I know better !" If the OP "knows better", then why was the question asked in the first place? Because the OP is looking for reinforcement for an idea that has not or will not work to give him the magic power gains he "knows" have been hidden by devious engineers. Black magic.

We fully understand that modern PCM spark tables are a constantly changing dynamic and therefore a "tuning" regression to load/mechanical ignition control is going back to 1930. 55 years of engine building and racing have taught me that there's more to "tuning" than black magic (although sometimes it helps........).

AJxtcman
08-30-09, 11:56 AM
Actually I have been thinking about PE mode more and more.

Think about this SUB.

PE (Power Enrichment) has several parameters. Some are delays and some are adders.

Lets go back a few years.
What throttle angle would you like your secondaries to kick in at?

I have found 80% on some of these!

I think 40% to 50% would be just fine. for the most part if you are in the throttle 40% you want to go.

Now for the delay or quadrabog
This is the length of delay before PE kicks in.
5 seconds is a long time

The second part of the Delay is RPM. LS1's used 1 RPM setting. Like 5000, so below 5000 has delay before it kick in and above skips over the delay time.

Now the Northstars have a table for delay RPM vs TPS

AJxtcman
08-30-09, 12:38 PM
This is from a Northstar PCM. Not the LS1 PCM setup.

Power Enrich Enable Delay Time Vs. TPS
TPS Seconds
0% 5.00
5% 5.00
10% 5.00
15% 5.00
20% 5.00
25% 5.00
30% 5.00
35% 5.00
40% 5.00
45% 5.00
50% 5.00
55% 5.00
60% 5.00
65% 5.00
70% 5.00
75% 5.00
80% 3.00
85% 1.00
90% 0.00
95% 0.00
100% 0.00



Power Enrich Enable % TPS Vs RPM
RPM TPS %
0% 75.00
400 75.00
800 75.00
1200 75.00
1600 75.00
2000 75.00
2400 75.00
2800 67.50
3200 60.00
3600 60.00
4000 60.00
4400 60.00
4800 60.00
5200 60.00
5600 60.00
6000 60.00
6400 60.00

AJxtcman
08-30-09, 01:15 PM
those who believe there is some magical way to tune a late Northstar FWD PCM for significant gains in power and "speed".


I have tried a read on a 2003 STS but I get denied access. Security access denied invalid authorization code when the type of car comes up it will tell me that it is a 2006 DTS it was unknown before my last update I think. It will tell me it is a 06 DTS on the scanner too


Nope, if our software won't read it its likely because we don't support the pcm and haven't written the bootloaders for it yet.


I have the ability to Recalibrate Northstar PCM's. I am working on unlocking more functions and a program to let people do it with a laptop.

As I have said all along I use TIS and a Tech II for Northstar's

Another conversation


do you have access to TIS and a Tech II or a MDI?


Yes, TIS2WEB (ACDelco TDS) plus a Mongoose and TechII.


Great I will send you an email on a process I use to flash custom tune with TIS.
Maybe you already know how.


Thanks but I really have no need, I have a feeling I know what you do though as all TIS files that get flashed are cached on the PC

As you can see from these conversations the main issue is the communication with the Cable and the PCM.
The way around that is the Tech II and TIS and I am not the only one that knows how to do that!!!!!!!!!!!!!!! :rant2:

Submariner409
08-31-09, 05:23 PM
:highfive: Good ol" Quadrabog - mostly brought on by those who fooled with the secondary air valve spring wrap, causing a big midrange stumble.

Most QJ secondaries (the mechanical linkage throttle butterflies) start at about 50% to 60% BUT the upper secondary air valve will not move until there's sufficient engine rpm and vacuum to begin to push them open, and secondary enrichment comes from the secondary air valve cam and hanger lifting the metering rods as the air valve rotates. If the engine does not have the cubic inches and air volume demand, the secondary air valve will never fully open regardless of the carb's CFM rating, so a QJ self-adjusts its airflow to each engine it is installed on. (Holley uses a somewhat similar self-metering approach with vacuum secondaries, you change to light secondary diaphragm springs and BINGO ! - midrange stumble.)

Not sure what those PCM enrichment tables are saying, but they are NOT saying that enrichment lags TPS by 5 seconds. Maybe 5 milliseconds, but not 5 seconds - that's enough time to hole a piston from lean burn at high rpm.

AJxtcman
08-31-09, 08:10 PM
Power Enrich Fuel
Power enrichment tables are used when the VCM detects wide open throttle (WOT) operation and provides extra enrichment to achieve maximum power.



Power Enrich Mode Delay
This constant specifies the amount of time (in seconds) the power enrichment is delayed after all the power enrichment enable conditions have been met.
Power Enrich Mode Delay Bypass RPM
If the engine RPM is above this threshold the Power Enrich Mode Delay will be bypassed. Above this RPM power enrichment will be enabled immediately after all the enable conditions have been satisfied.



This is from a 99 Chevy Truck 5.7L 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEDelay350truck.jpg

This is from a 2004 SSR truck with a 5.3L 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEDelaySSR.jpg

This is from a 2004 Silverado SS 6.0L 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEDelaySSSilverado.jpg

This is from a 2002 Carmaro LS1 Z28 with a 5.7 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEdelay5.jpg

This is from a 2003 3800 Bonnie 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEdelay3800.jpg

This is from a a 2000 car with a 5 second delay just like a Northstar 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEDelay5second.jpg

N0DIH
08-31-09, 08:18 PM
Like my 454, setup for HD towing, is 60 seconds! And the bypass rpm is set to 4900 rpm, redline is set to 4500! So you will never see it.

So that means when you are towing that 10K trailer through the pass on I70 in Colorado west of Denver, you are towing heavy @ 14.7:1

http://i159.photobucket.com/albums/t142/mompower/Tom/PCMTuning/PEMode454.jpg

So even if you back off for more than 0.2 seconds it will reset the PE Mode timer and you will have to wait again for 60 seconds to get enrichment back.

And people wonder why the 454's were dogs. This is why. ALL 2500 and 3500 trucks/vans are setup this way, 100%, Ford and GM even. Ford V10, LQ4 6.0L, L29 454, L31 350. All with a 60 sec delay. 1500's didn't get the 60 sec delay, but the 2500/3500's did.

Submariner409
09-01-09, 06:43 PM
OK - I missed the rapidly decreasing delay times at 80%+ throttle opening - and the PCM also delays timing quite a bit at part-throttle acceleration.

Looks like on a 2000+ Northstar, if you stick your foot in the firewall, enrichment comes immediately.

AJxtcman
09-01-09, 08:43 PM
It isn't the same for all of them.

Exports with RPO K29 PCM or R1X Noise Control have a 2 second delay before the car downshifts. This is a very common export RPO. That means German Export cars suck.

Now this is a Factory Hot Rod
This is from a 2004 Silverado SS 6.0L 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEDelaySSSilverado.jpg

Now this is a Stock 6.0L PE Delay from a Burb
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/Daves6.jpg

This is a Stock 02 GMC Denali 6.0L PE Delay
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/02Denali6.jpg

This is a Stock 02 GMC Truck 6.0L PE Delay
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/02GMC6.jpg

This is a Stock 02 Escalade 6.0L PE Delay
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/02Escalade6.jpg


Now not all of the other PE parameters are the same on the ones with 0.00 second delay and the same goes for the ones with a 60 second delay.

GM has this stuff all over the board

N0DIH
09-01-09, 09:24 PM
Some do, you would think the HD trucks that have the huge delay in PE mode would eat pistons or something, but they don't. I think it relys on Piston Protection Mode and/or Cat Converter Over Temp (COT) mode to enrichen, but it is typically VERY rich, like 10.5 - 11:1. So it goes whacko in fueling.

I am guessing that it the >8600 GVW Emissions Cert that covers the pathetic things they do.

It will help mpg some by keeping you out of PE so easily, like my 454 has a stock PE Mode table (and how much it adds, think EQ Ratio as the Stoich - EQ Ratio = Commanded AFR) like this:

But as you can see, on a 454, yes, the vaunted 454, PE mode is forever cursed @ 60 seconds! Even if you flatten your foot on the firewall for the whole quarter mile or more! Or imagine with a trailer in tow, 10K worth trying to move into traffic and never get the extra power from PE Mode.

What good is a good engine if you can never use the power from it? And to make matters worse, GM installed the cam on the 454's 6-9 degrees retarded!

http://i159.photobucket.com/albums/t142/mompower/Tom/PCMTuning/PEMode454-1.jpg



OK - I missed the rapidly decreasing delay times at 80%+ throttle opening - and the PCM also delays timing quite a bit at part-throttle acceleration.

Looks like on a 2000+ Northstar, if you stick your foot in the firewall, enrichment comes immediately.

N0DIH
09-01-09, 09:29 PM
Yup, what I have noticed is LQ4's are never put in 1500's, so they get the cursed 60 sec PE mode timer, but the LQ9's are only put in 1500's and they do NOT get the PE Mode timer set to 60 seconds....




It isn't the same for all of them.

Exports with RPO K29 PCM or R1X Noise Control have a 2 second delay before the car downshifts. This is a very common export RPO. That means German Export cars suck.

Now this is a Factory Hot Rod
This is from a 2004 Silverado SS 6.0L 100% stock tune
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/PEDelaySSSilverado.jpg

Now this is a Stock 6.0L PE Delay from a Burb
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/Daves6.jpg

This is a Stock 02 GMC Denali 6.0L PE Delay
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/02Denali6.jpg

This is a Stock 02 GMC Truck 6.0L PE Delay
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/02GMC6.jpg

This is a Stock 02 Escalade 6.0L PE Delay
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/02Escalade6.jpg


Now not all of the other PE parameters are the same on the ones with 0.00 second delay and the same goes for the ones with a 60 second delay.

GM has this stuff all over the board

Submariner409
09-01-09, 11:44 PM
N0DIH, Your observation that most GM 454 cams are retarded is spot on. Even in the marine engine realm, we find that the engines are running with a log tied to them: cam timing.

Retard the cam and the power band moves higher in the rpm range, costing midrange torque and power. Advance the cam (4 degrees) when you stab it in and the power band moves down a tad, giving a midrange lift in torque and power: the cam "comes in" faster. Allowing for chain stretch and age, the cam will still be in timing specs tens of thousands of miles (or hundreds of hours) out............Many cams are purposely ground with about 2 degrees of advance for just that reason.

(Kicker is that we're fooling with Northstars and not 454's or any other non-Northstar engine, so all the above non-Northstar tables are moot and serve no purpose other than to add to the confusion.)

N0DIH
09-01-09, 11:56 PM
Agreed, I was showing what GM does on the engines, we have found on nearly all have the PE Delay in some sort. Performance engines often have none, and non have several seconds to as long as a minute....




(Kicker is that we're fooling with Northstars and not 454's or any other non-Northstar engine, so all the above non-Northstar tables are moot and serve no purpose other than to add to the confusion.)

Submariner409
09-02-09, 12:19 AM
What's the rationale for holding off on power enrichment for such lengths of time ? Emissions ? Efficiency ?

A well-tuned QJ or Holley, allowing almost immediate enrichment at any point in the throttle opening, can be an incredibly clean burning carburetor. Why the electronic delays - when an electronically adjusted fuel delivery is much faster in response than a mechanical system ?

N0DIH
09-02-09, 12:30 AM
My guess on the heavy trucks is towing they would be in PE mode a lot and aside from mpg, the emissions could be "bad" or out of 14.7 as that is the only place the cat converter is efficient at would be "turned off" essentially the whole time and the converter also would cool down. So it keeps emissions better on average at the sacrifice of power.

AJxtcman
09-02-09, 07:20 AM
This is from a Northstar PCM. Not the LS1 PCM setup.

Power Enrich Enable Delay Time Vs. TPS
TPS Seconds
0% 5.00
5% 5.00
10% 5.00
15% 5.00
20% 5.00
25% 5.00
30% 5.00
35% 5.00
40% 5.00
45% 5.00
50% 5.00
55% 5.00
60% 5.00
65% 5.00
70% 5.00
75% 5.00
80% 3.00
85% 1.00
90% 0.00
95% 0.00
100% 0.00



Power Enrich Enable % TPS Vs RPM
RPM TPS %
0% 75.00
400 75.00
800 75.00
1200 75.00
1600 75.00
2000 75.00
2400 75.00
2800 67.50
3200 60.00
3600 60.00
4000 60.00
4400 60.00
4800 60.00
5200 60.00
5600 60.00
6000 60.00
6400 60.00


N0DIH, Your observation that most GM 454 cams are retarded is spot on. Even in the marine engine realm, we find that the engines are running with a log tied to them: cam timing.

Retard the cam and the power band moves higher in the rpm range, costing midrange torque and power. Advance the cam (4 degrees) when you stab it in and the power band moves down a tad, giving a midrange lift in torque and power: the cam "comes in" faster. Allowing for chain stretch and age, the cam will still be in timing specs tens of thousands of miles (or hundreds of hours) out............Many cams are purposely ground with about 2 degrees of advance for just that reason.

(Kicker is that we're fooling with Northstars and not 454's or any other non-Northstar engine, so all the above non-Northstar tables are moot and serve no purpose other than to add to the confusion.)

The thing is the code above is an 2000 to 2003 Northstar!!!!!!!!!!!!!

This is a 2006 DTS PE
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/06DTSPE.jpg


This is a 07 XLR PE.
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Tables/07XLR.jpg

AJxtcman
01-24-11, 06:04 PM
Would anyone purchase HP Tuners if they supported Northstars? What if it cost $750 per car?