Migrating from an LS1-Edit tune

[JimMueller]

Is it safe to just download my current LS1-Edit tune and continue from there like the calibration was stock?

I've altered timing, VE, fuel, PE, etc. I seem to recall some are recommending leaving the IFR stock to accurately reflect stock injectors - and make the changes directly in Main VE.

For instance, the process of monitoring the LTFT/STFT histograms and changing the VE in the matching cell. Which values do I use in the histograms to base my alterations upon (last, min, max, avg)? If my LTFT @ 55x0.8 is +6, and the STFT is +0, then my final % learned is 6%.

So I guess my initial questions are:

1. Do I modify my IFR, leave it as is, or return it to stock (for my stock injectors)?

2. If my VE in that above cell is 45, is the calculation (45+6) or (45*1.06)?

3. What are the benefits of being able to alter the LTFT boundaries?

4. Should I disconnect the MAF to tune the VE table with my LM-1, or force closed loop and just use trims?

5. What's the easiest way to force closed loop?

6. What are the general steps to follow: i.e., tune VE via LTFT's, then tune PE via my LM-1, then achive max timing w/o KR in Main .

HPT is a lot more robust and "I don't wanna die for lack of shootin' "

[jimmyblue]

Is it safe to just download my current LS1-Edit tune and continue from there like the calibration was stock?

Yes, HPTuners just works with what it finds. It makes no
changes without you directing.

I've altered timing, VE, fuel, PE, etc. I seem to recall some are recommending leaving the IFR stock to accurately reflect stock injectors - and make the changes directly in Main VE.

All years have the Primary VE table. Earlier years have a
Secondary that is used under fault conditions (like an unplugged MAF).
So on the early-years cars when working in SD you have to work in the
Secondary table, then propagate your changes to the Primary, fill in
the "missing" rows and then that table will be used when / if you plug
the MAF back in.

For instance, the process of monitoring the LTFT/STFT histograms and changing the VE in the matching cell. Which values do I use in the histograms to base my alterations upon (last, min, max, avg)? If my LTFT @ 55x0.8 is +6, and the STFT is +0, then my final % learned is 6%.

So I guess my initial questions are:

1. Do I modify my IFR, leave it as is, or return it to stock (for my stock injectors)?

I recommend returning IFR to stock. Remember the change amount
because this is what {something} wants, to be right.

2. If my VE in that above cell is 45, is the calculation (45+6) or (45*1.06)?

45+6, but remember the IFR table? What enrichment baseline
did that represent? Might be more needed.

3. What are the benefits of being able to alter the LTFT boundaries?

Cleaner trimming by segmenting the actual closed loop load
space more finely, where it counts. Easier to figure out what
actors are most relevant (VE at low RPM, MAF at high RMP,
etc and see changes' effects with less "random" drift (really
from very different corrections applied at, say, 600RPM and
2499 RPM due to very different engine operating point &
airflow calculation mode).


4. Should I disconnect the MAF to tune the VE table with my LM-1, or force closed loop and just use trims?

Hard to trim VE cleanly when some of the airflow calc
and some of the trim is MAF based. Taking out the MAF will force
speed density mode, not open/closed loop. If you also force open
loop then you can use the O2s as rich/lean indicators. If you enable
closed loop then the trims are what you'd go by. Don't know if you
can "force" closed loop. More like, enable (= not forcing open loop).
Closed loop is "fragile", needs O2s working, temperature met, etc.


5. What's the easiest way to force closed loop?

6. What are the general steps to follow: i.e., tune VE via LTFT's, then tune PE via my LM-1, then achive max timing w/o KR in Main .

HPT is a lot more robust and "I don't wanna die for lack of shootin' " [/quote]

[Screamn03]

1. Do I modify my IFR, leave it as is, or return it to stock (for my stock injectors)?

IMO, leave it alone if you have stock injectors. Stock Injectors=Stock IFR

2. If my VE in that above cell is 45, is the calculation (45+6) or (45*1.06)?

I get good results by adding or subtracting the difference, in your case +6.

3. What are the benefits of being able to alter the LTFT boundaries?

As per the great word of Jimmyblue:

Many models seem to have stock fuel trim cell
boundaries that are "kooky" - they make the car
trim using only 8 of the possible 16 cells, and I
believe this contributes to the difficulty some
folks have with tuning the VE table and getting
good stable fuel trims.

The relative weighting of the MAF airflow value in
the mass air calculation "slides" from 0 at low RPM
to 100% by 4000RPM. If your car (like mine) has the
FTC RPM boundaries at 2500, 6502, 6503 then FTC
0, 4, 8, 12 are all having to hold trim across a region
where not only is the VE table very variable, but the
weight given to SD vs MAF as well (not to mention
the O2s' heat which is a prime idle-messer-upper).

Setting the boundaries to 1000, 2000, 4000 is what
I picked for my car. Just-above-idle, {split-the-difference},
MAF-takes-over.

Similarly for the MAP boundaries there is not much use
in having all 3 boundaries lie below your idle and cruise
MAP normal value. Now if you have an idle that's way up
but MAP comes down with RPM a bit, you don't want the
boundaries to be all about idle. And I suspect there is
little or no point to having the lower two boundaries
above PE enable threshold; throw away no more than
one row on open loop cells and one row on idle. Using
the LTFT histogram as a guide you can draw the lines
wherever it mayes sense to your eye, given the realities
of how the MAD/SD blending works and where you find
your closed loop operation really lies (check the PE MAP
and TPS thresholds; zero your trim table and find the
points where, for your setup, you are really running
closed loop by where you find trims updating quickly).
Then "shrink the boundaries to fit" so you are "wasting"
no more than the lowest row (RPM) and rightmost column
(MAP) of the FTC matrix on non-closed-loop operation.

How this all plays with cars that have crazy high idle MAP
is something I haven't doped out yet, but the basic idea
is to divvy up the space that matters to closed loop, as
finely as possible so that one trim value better represents
the area it covers (by the area not being insanely broad
and variable in mixture). This reduces how much the trim
jitters around based on recent driving history, and makes
the effect of VE or MAF cal changes more clear and direct.

It doesn't affect performance any, just offers some
straightening-out of the tune/trim situation.

4. Should I disconnect the MAF to tune the VE table with my LM-1, or force closed loop and just use trims?

I did mine with the MAF disconnected because I didn't have the LM-1 at the time nor the EIO interface or V1.5.0. If you do disconnect the MAF the engine will operate in the Low Octane spark table. Copy the High Octane map into the Low octane map while you have the MAF disconnected.

5. What's the easiest way to force closed loop?

I don't understand why you would have to force closed loop. I think you mean force open loop so the computer will never go into closed loop. If that's the case then you want to set the closed loop enable temp to something the motor will never see, like 260*F.

6. What are the general steps to follow: i.e., tune VE via LTFT's, then tune PE via my LM-1, then achive max timing w/o KR in Main .

WS6snake-eater came up with this:
Step by Step for SD tuning:

1: Unplug and replace MAF with a strait bellows (less airflow dispruption creates a better VE)
2: Disable MAF codes (No check engine light) EDIT:Skip this step, see post by WS6snakereater elsewhere in this thread
3: Change all points from 122* and greater to 1.13 in the Open Loop F/A vs ECT vs MAP table (commands AFR of 13.0)
4: Change all points in the Closed Loop Enable Coolant Temp vs IAT table to 250* (Disables closed loop)
5: Copy High Octane table to the Low Octane Table (computer reverts to low octane table when MAF is unplugged, this assure optimal timing)
6: Change all points in the Power Enrich Fuel Multiplier vs RPM table to 1.0 (disables PE mode)
7: Use wideband to verify AFR of 13.0
8: Make adjustments to the VE table accordingly to dial in a 13.0 AFR (a lot of driving or dyno time)
9: Hand smooth VE as described by Magnus (a smooth VE results in crisper throttle response)
10: Change all points in Open Loop F/A vs ECT vs MAP table back to stock (re-enable stoich commanded AFR)
11: Change all points in the Closed Loop Enable Coolant Temp vs IAT table back to stock (re-enables closed loop operation and fuel trim leaning)
12: Change all points in the Power Enrich Fuel Mulitiplier vs RPM table back to stock (re-enables PE mode)
13: Use wideband and PE table to dial in desired WOT AFR. (optimum HP at WOT)



-Mike


EDIT:WS6snake-Eater created a thread just about VE tuning, see it here:

[JimMueller]

1) OK, so I'll revert to stock IFR. If I am to keep track of the differences between my current IFR and stock, where do I apply those differences which I'm tracking?

2) This may be part of #1; so if my IFR @ 70KPa is currently 27, and stock is 31, what do I do with the difference of '4', and where do I use it? Won't the histogram tell me what it's supposed to be without tracking the difference manually? And if I get the histogram where it's supposed to be on STFT/LTFT's, my LTFT's should lock at 0 in PE, right?

3) Can you make any recommendations on values to set them at during the course of this process?

4) Yes, my bad. I meant keep it in open loop. So I can just disable LTFT Enable, change my CL enable to 260* from IAT 14*+ and it won't go into CL, correct? So what's quicker to fix VE - using both the LTFT & STFT histograms, or just the STFT histogram?

[JimMueller]

SD Tuning: If you're planning to keep the MAF, wouldn't you leave it in place and just disable the codes to get an accurate VE? Everything else I can follow.

LTFT Boundaries: Defining new MAP boundaries sounds like a pain. Can I get by with just setting the RPM boundaries? Do I need to keep moving the RPM boundaries around to isolate other sections of the tables? Do I need to move it back to stock when done?

Dang, maybe I should just take a 3-hour drive south to visit Jimmy. What are you doing tomorrow? ;D

[Screamn03]

SD Tuning: If you're planning to keep the MAF, wouldn't you leave it in place and just disable the codes to get an accurate VE? Everything else I can follow.

Something bad happens if you do that but I forget what it was. Quick answer is NO.

[Screamn03]

Jim,
Can you also create a signature with your car type and modification that way we know what you're working with? You can do that by clicking on the profile button at the very top of the page right underneith the black WS6.

[JimMueller]

Whoops. I put in the basics. No room for the suspension stuff, etc.

[Screamn03]

LTFT Boundaries: Defining new MAP boundaries sounds like a pain. Can I get by with just setting the RPM boundaries? Do I need to keep moving the RPM boundaries around to isolate other sections of the tables? Do I need to move it back to stock when done?

With the cam you have where does it idle as far as MAP values?

[JimMueller]

Hmm, actually, can I just force both closed loop and Fuel trim learn off in the VCM Controls, reset the fuel trims, and begin logging? When do these controls revert back to normal? Closing the window, ignition off, etc?

MAP @ idle is ~7-8kPa. I have a ~20 min CSV from driving home with the default PID's if you care to look. *shrug*

[Screamn03]

MAP @ idle is ~7-8kPa.

Do you mean 70-80kPa? You loggs are in in/hg or psi or something. I think you mean 48-55kPa.

[JimMueller]

The log file column Manifold Absolute Pressure (SAE) kPa says it's 7.x at idle. Is that the wrong PID?

[Screamn03]

The log file column Manifold Absolute Pressure (SAE) kPa says it's 7.x at idle. Is that the wrong PID?

No you have to convert that to kPa using the tools->unit conversion in the editor.

[JimMueller]

Hmm, so why does the scanner say it's in kPa when it's really in PSI?

So I guess it's really ~48-55kPa, which you've already guessed.

[Screamn03]

Hmm, so why does the scanner say it's in kPa when it's really in PSI?

So I guess it's really ~48-55kPa, which you've already guessed.

The scanner says psi,kpa so I think you need to right click on that peticular PID and select metric that way it will logg kpa instead of PSI. This is a new feature of V1.5.0 that I wasn't aware of until now. Thanks


BTW:I accidentally started to edit your post, my bad, I didn't know I could do that :-[.

[JimMueller]

I re-opened the default.cfg (modified 10/19/04), and when I right-click on it, Metric is already checked. ???

So do I need to alter my MAP boundaries?

[JimMueller]

OK, so it looks like the PCM is vacuum referenced while the tables are absolute referenced. Why not use common units between the scanner and editor?

[Screamn03]

So do I need to alter my MAP boundaries?

I would and this is an example why:

Stock FTC Boundries
2500 rpm low
6502 rpm mid
6503 rpm high
32 map low
57 map mid
77 map high

My FTC Boundries
1000 rpm low
2000 rpm mid
4000 rpm high
42 map low
60 map mid
80 map high

I did this based off of Jimmyblues post that I quoted above.

because...
my car idles at 38-40 kpa so with the stock setting of 32 I would never see that. Idle to 2500 rpm is where alot of normal driving is done so that's why I have the rpm set the way I do. I figure why not have a dedicated FTC for just idle that way that cell only has to concentrate on that and not idle, part throttle take off, and cruise. All it does is just break up the "work load" of each FTC by utilizeing more of them.

[Screamn03]

Hmm, so why does the scanner say it's in kPa when it's really in PSI?

OK, so it looks like the PCM is vacuum referenced while the tables are absolute referenced. Why not use common units between the scanner and editor?

I have no idea ???

[JimMueller]

According to a stock 1998 tune I pulled off Horist's site, mine were originally (and were up until now):

Stock FTC Boundaries
900 rpm low
1400 rpm mid
2200 rpm high
37 map low
57 map mid
77 map high

My idle is 850, but my idle can be as high as 1100 depending upon temp. I also am entering PE at lower than stock TPS.

Proposed FTC Boundaries
1200 rpm low
2400 rpm mid
4000 rpm high
60 map low [idle map is 48-55]
?? map mid
?? map high

How do I determine the upper limit for mid- and high-map? My highest logged absolute map during my 20-minute drive home in bad traffic was ~99kPa, between 2500-5400 RPM. I guess I'll set the high to 105, and the mid to 80 {just about half way}.