Tuning for headers - B4105 question

[derekf]

Bought a new (to me) LS1 car - 98 Trans Am.

Seller won't respond to questions now that he's got his money, so the only things I know for sure about the engine is that it has LT headers (supposedly Pacesetter) into 3" duals, and it has a giant K&N mostrosity for the filter. Believe the MAF is ported, but I have low expectations as to how well.

Tune compares as identical to the GM tune #19980100 so it doesn't look like anyone's ever done a tune. I've got an LC1, but I haven't installed it yet to do any WB logging.

Using the search, I found several threads that mention that for LT headers, the o2 switch points should be set to more like 450... but {B4105} has different rows for different "CL Modes" and some are above 450 and some are below already. Seems to me that this is something that should probably be set before adjusting other tables; can someone point me at a reference that defines the "CL Modes" or give a pointer as to which rows should be set to 450?

If it matters, my LTFTs are pretty much -10 across the board. Can, of course, get specifics as needed.

[WeathermanShawn]

Hi there..

It gets fairly complicated. For tuning MAF and/or VE utilizing closed-loop, a number of us have had more success utilizing an unilateral mv switch-point reading. Many use 450 mv as that 'equates' to ~14.7 AFR. I occasionally use 550mv. That reading keeps my closed-loop AFR closet to stoich (~14.63 AFR).

I believe the theory is that as you get into higher airflow (CL Modes) the ability of the narrowband to 'cool' increases..hence the differing mv to its respective CL Mode (airflow).

My advice is not to 'sweat the small stuff' too much at this point. Personally, I see no downside to just using 450mv for every CL Mode. The whole process of CL Modes becomes more important if you tune utilizing closed-loop and LTFTBEN's.

It is more of a refinement concept to tuning, than basic. Save it for later would be my advice.

Hope that helps..

[joecar]

Post log and tune files.

[derekf]

Tune is literally the default GM tune 19980100 (98 Trans Am/manual).

No log with me here at work, will post when I am home.

Edit: Are the following the PIDs you'd want to see?

VSS
TP
RPM
DYNCYLAIR or DYNCYLAIR_DMA
DYNAIR
MAF (SAE or GM)
MAP (SAE)
DYNAIRTMP_DMA
IAT
ECT
EQIVRATIO or AFR
SPARKADV
KR
LONGFT1
LONGFT2
HO2S11 (not HO2S12 or HO2S22)
HO2S21 (not HO2S12 or HO2S22)
MFTOTAL

(I don't have the LC-1 installed yet to get WB O2 numbers)

[WeathermanShawn]

If you do not exceed 24 channels, you might try to log MAF Frequency. Perhaps dump Misfire Pid? That way we can compare it against your LTFT's across the MAF Frequency range.

Without starting a huge Internet battle, here are a few points to ponder. Radical air-boxes and filters along with ported MAF's do not always supply more airflow into the engine, but simply disrupt the MAF airflow. And that drives your Trims crazy.

Probably a nice high-flow LS1 Lid and filter along with a stock MAF, will deliver within 5HP of your current setup and be a lot easier to tune. With the headers, the type and location of the narrow-bands will determine how they are switching.

A good log will help.

[derekf]

Couldn't log DYNAIRTMP_DMA - said it wasn't a supported PID.

8587

Not really sure how I should be driving while logging - I don't think I got to full throttle, and I'm sure I didn't break 60mph (too many cops around). Looks like I may have been misremembering the LTFTs as it looks like everything is +10ish rather than -10ish.

[WeathermanShawn]

Derek:

Don't worry about logging and driving. I have logged over 30,000 miles without a ticket or incident. By all means, do not stare at your laptop while driving! If you are using a laptop you can set up audible alarms that will sound when you have KR, ECT too high etc.

Use your drive gears as much as possible. There is no law against safely taking an on-ramp in a spirited manner, but if you don't feel comfortable stick to the track or a dyno.

As far as your log..

1. Need a wideband hooked up (mandatory).
2. Your LTFT's are very high. You need to adjust the MAF and VE Table. (see CALC.VE Tutorial in my sig).
3. Your O2's look like they are switching too slow in spots. How old are they, and where are they located?
4. Way too much KR. Some of low RPM. Are you gunning the engine? Once your fueling is down then you can work on spark.
5. Your IAT's are way too high! You need to log in cooler weather, or get some ambient air in there.

I would read through the CALC.VE Table Tutorial. With a wideband and fresh O2's, it should only take 2-3 logs to go from a questionable tune to a very good one.

Good luck (and do not take my criticism personally). Better to get it right by knowing what needs to be addressed..

[derekf]

I appreciate the feedback, and I don't see anything to take personal.

Wideband probably this weekend.

No idea how old the sensors are, but they're in the collectors of the long-tube headers. Is that the problem or do I need to replace them?

Not sure what you're asking when you ask if I'm gunning the engine.

As for IATs - this is Texas in July, cooler weather will have to wait for October or so - ambient air is 101F today or so :)

[joecar]

+1 NBO2's are switching slowly, less than 2 times/second... good ones will switch faster than 4 times/second.

If the NBO2's are aolder than 60K miles or if they are fouled then they probably should be replaced.

[WeathermanShawn]

I appreciate the feedback, and I don't see anything to take personal.

Wideband probably this weekend.

Good idea!

No idea how old the sensors are, but they're in the collectors of the long-tube headers. Is that the problem or do I need to replace them?

They are switching..they just seemed a little sluggish. New ones can't hurt though.

Not sure what you're asking when you ask if I'm gunning the engine.

Derek..see attachment. On frame 1, you are at 650 Rpm with a TP% of 25% and 5 degrees of KR. I am just trying to understand why?

As for IATs - this is Texas in July, cooler weather will have to wait for October or so - ambient air is 101F today or so :)

No, I understand. Denver hit 101F this week, but I kept my ambient right at 101F. Might look into a Free Air Mod to get it cooler. 136F is heat soak and will really hurt tuning.




Keep at it. There are just a few issues to ponder..

[derekf]

Derek..see attachment. On frame 1, you are at 650 Rpm with a TP% of 25% and 5 degrees of KR. I am just trying to understand why?

Reckon that might explain the bogging/jerking I feel when I first start off from a dead stop. Figured it was just that I didn't quite remember how to drive a standard (been years, just had the car a week or so) but I suppose KR would do it.

So new NBO2s are first up, or the wideband?

Edit: or is there something I need to do about the KR first? This is with high-grade (93 octane, plus all gas in Dallas County is 10% ethanol)

[WeathermanShawn]

Reckon that might explain the bogging/jerking I feel when I first start off from a dead stop. Figured it was just that I didn't quite remember how to drive a standard (been years, just had the car a week or so) but I suppose KR would do it.

Yea, I wasn't sure if you were just spinning your tires, or if ABS (Traction Control) was kicking in. I say that, because it looks like your Spark dropped to 2.5 degrees..:confused:..Very odd..

So new NBO2s are first up, or the wideband?

Wow, I really hope it is not truly an either or. Your narrow-bands probably need replacing, but I would opt for a wideband no matter what. At least you will be able to accurately determine your AFR, both at stoich and WOT.

Edit: or is there something I need to do about the KR first? This is with high-grade (93 octane, plus all gas in Dallas County is 10% ethanol)

1. Get Wideband.
2. Get narrowbands.
3. Get LTFT's/AFR accurate.
4. Work on Spark.



As long as your tune is stock, then at least Spark should drop to Low-Octane as determined by the Adaptive Spark feature. I would never say to not worry about KR, but I think fueling is #1. You could always copy your Low-Octane Spark over to High-octane until you get it figured out..

[derekf]

Here's where the stream of profanity comes in.

I've had a new LC-1 sitting in a box in my garage for five years now. Finally installed it in something... and it doesn't work. Used the instructions at http://www.innovatemotorsports.com/resources/efilive_lc1_tutorial.pdf and it won't do the free air calibration and I can't connect via LM Programmer. I'll be writing a support email next.

However, I also installed new O2 sensors today and took new logs (even though I didn't have a functional wideband, grumble grumble).
8614
8613

Not sure if I'm wasting my time taking new logs, but I suppose at least y'all can verify that the new sensors are working better than the old ones. I did go through the steps in the calc.ve tutorial and I think that I got the PIDs right. It doesn't look like I'm getting the serious KR off-idle that was in the last log, anyway.

(edit: maybe you can't tell me that the new O2 sensors are working better, since the HO2 PIDs aren't in this latest log)

(edit2: GM.DYNAIRTMP_DMA isn't a "valid PID". Is there something I need to be doing to make it valid? Also, somehow I lost MAFFREQ as a PID so it's not logged. Might mean that these logs are completely useless)

[WeathermanShawn]

Sounds like you just need to slow down and try one thing at a time.

There are numerous tuners on this board who can help you with connecting the wideband (not my best talent). Then you probably just need some help in validating your PIDS and selecting the correct ones. You can always verify them prior to logging.

One hint on PIDS, especially DYNAIRTMP.DMA..keep all units in metric. That includes your MAF Airflow..make it g/s. As far as I can tell there is no reason DYNAIRTMP.DMA should not be valid for your OS.

When you take a day off or two, try another log. With your logging of the O2's and MAF Frequency, one can tell a lot. As it is now, you look like your entire MAF Calibration Table will end up being an overall +10%. But, we need more logging.

You might want to start a separate thread for some of your issues. Hope that helps.

[joecar]

derekf,

How is your LC-1 wired up...?

Where do the black and white wires go...?

[joecar]

Logs are always good... don't assume new parts will work (I've had my share of faulty new parts).

Add these pids when you next log:
HO2S11
HO2S21
TP

[derekf]

Black wires go through the button and LED (in parallel) to ground.
White is connected to input D.

Will add those PIDs to next log.

[derekf]

New logs.

WB still not working right (separate thread for that), but I've got the NBs and MAFFREQ in this one.
8619
8618

[WeathermanShawn]

Well, your O2's seem to be switching a little slower than normal, but the amplitude looks fine. Mine are the rear Corvette type..I have them right after the header collector and before the cats.

I posted several attachments as an example.

If you simply copy with labels (MAF vs LTFTBEN MAP) and then paste and multiply with labels against your MAF Calibration Table, you can see how easy it would be to calibrate your MAF. Very easy. See the CALC.VE Tutorial in my signature for more information.

I just looked at your log very briefly. If I see something else I will let you know..

[derekf]

Thanks for all the help, Shawn and Joe.

Should there be anything done with the MAF frequencies less than 2500rpm? Even if I turn off the empty cell hiding, there's no data in that map for thost RPMs.

[WeathermanShawn]

I usually add the average LTFTBEN to frequencies down to 1500 Hz. Even though you have no logged data, if from some reason you go to higher elevation or your Idle Rpm drops you will hit some of those lower frequencies.

I.E., I keep the same MAF slope..in your case I believe it was +10% LTFT average. Note, when you get your wideband up and running, you will have to switch to the AFRBEN for PE Mode and WOT. In PE mode, you are no longer in closed-loop. It is in essence a form of open-loop. If you get stuck on that, just let us know.

When you get your LTFTBENS ironed out and can log DYNAIRTMP.DMA, it will be a cinch to complete your CALC.VE Table.

Let us know how it goes..Good luck!

[derekf]

Even if I "validate PIDs" before I start monitoring/logging, DYNAIRTMP_DMA isn't considered a "valid PID". Is that maybe something that isn't in 19980100? Is there an alterate PID I could use?

[WeathermanShawn]

Its possible that it is not in that OS.

I'll look up an alternative reference..I'll get back to you..

************************************************** ************************************************

I would PM Joecar or do a 'shout-out'. I am not sure why 98's are not supported..

Basically, it will take a Calculated PID that uses a blend of the ECT & IAT or the use of a 'Look-up' Table to replace DYNAIRTMP. I have been plodding along attempting to develop an alternative charge temperature method..I just need to do more work on it.

Hope that helps...

[joecar]

Yes, DYNAIRTMP_DMA may not be defined for 1980x000 OS's...

use the method that Shawn shows, you use the (x,y) values from your IAT/ECT blend table B4901...

Also see posts #17 and 29 here: showthread.php?13217-some-invalidated-pids&p=117959&viewfull=1#post117959 (http://forum.efilive.com/showthread.php?13217-some-invalidated-pids&p=117959&viewfull=1#post117959)

[derekf]

I don't have DYNAIRTMP_DMA to compare against to make sure that the values are comparable, but I'm guessing that I replace GM.DYNAIRTMP_DMA.C in the Calc.VE_Table calculated PID with this new CALC.DYNAIRTMP -- or are there additional changes that are needed to the Calc.VE_Table PID?

[WeathermanShawn]

I believe it should.

I will say it may not be a 'perfect' replacement for the DYNAIRTMP.DMA PID. Sometimes the 'Look-Up Table' method has an interpolation problem at the lowest Airflow Value. I also suffered a 'lag' in the value when I logged it. But, I did it via laptop. BBL may not suffer the same issue.

If you are good with Statistical Analysis, you might be able to mathematically display a factor based on the following (see attachment). The Charge Temperature Factor follows a progression from Low-Airflow to High. So, you could use the 'old' CALC.VE formula and apply a correction factor after the fact.

Thats what I have been working on..:grin:

[derekf]

I don't know that this is right, I must have done something wrong in here - the values I'm seeing in the CALC.VE_Table after a somewhat long log range from about 55 to 82, and it seems more like they should be roughly 1.0 give or take to do the "multiply with labels".

8697

[joecar]

CALC.VE_Table calculates the actual VE (or rather the normalized cylinder airmass)... it is not a multiplier, but the actual VE.

CALC.VE_Table has units of either [%] or [g*K/kPa].

In the tunetool options set the VE units to either of [%] or [g*K/kPa], and then in the scantool use the same units for CALC.VE_Table.

[derekf]

Ok - so this would replace the values I already have?

For example - 20kPa @ 1600 rpm would become 61.9 instead of the existing 49.67?

[joecar]

Yes it replaces existing values.

[WeathermanShawn]

Derek:

Those CALC.VE Table Values you posted seem unusually high..:confused:.

From your log, I am getting a constant DYNAIRTMP of 194.9C. Obviously something is wrong..:confused:

[derekf]

I don't know if the matching of PIDs in a log to the slot# matters; I suppose they do since I shuffled the numbers around and you ain't seeing what I'm seeing... on my end I'm seeing DYNAIRTMP ranging from 38.5 to 70.7.

For me, DYNAIRTMP is CLC-00-003 and the VE_Table is CLC-00-004. I adjusted both the slot definitions and the param reference numbers to match.

Or perhaps I'm looking at things wrong, but it doesn't look like it was constant on my end.

[WeathermanShawn]

Yea, it is probably because my DYNAIRTMP.DMA is a different Calculated PID. I didn't think about that.

Do your CALC.VE Table #'s look 'sane'?

[derekf]

I don't really know how to define "sane"; that was what was confusing me a few posts back - the averages seem to range from about 51 (2800 rpm at 15kPa) to roughly 81 (2400 rpm at 90kPa)?

Stock tune had 40.19 and 73.25 in those same locations, so I suppose both are improved by ~10ish?

Edit: I find myself thinking that the reordering was not needed; the MAP wouldn't select the new DYNAIRTMP and I found myself thinking it was because slot 3 was depending on a variable defined later (it was actually because I hadn't selected the new PID in the PID list)

[joecar]

Post your calc_pids.txt file.

[WeathermanShawn]

Dereck:

Just to clarify..You are still running the stock 98 LS1 Tune, correct? And, your O2 sensors are located opposite each other? I.E. One on Driver's side, and one on Passenger side?

We need to work on these issues separately, but I still do not know if I understand the pattern of your narrowband switching. They almost seem in unison at times.:confused:.

I also see 4 degrees of KR at one point. Looks like you did a WOT at a fairly low RPM. So, I don't know if you are simply bogging the engine and picking up KR, or if it is that Texas heat.

So a few issues. but I guess we can address them one at a time..

[derekf]

Yes - O2 sensors are close to the back ends of LT headers, one on each side.

This is the stock 98 LS tune, except for stoich has been set to 14.12 and we've altered the MAFFREQ table.

As requested, my calc_pids.txt - 8698

If all goes well, I'll be invalidating all this work today; in theory I'm picking up a flowmaster exhaust setup to replace the 3" duals (unless the deal falls through), so there will be quite a bit more backpressure in the system.

[joecar]

Your CALC.DYNAIRTMP graph follows your IAT (I set the °C scale to convert with the 0-240°F scale on my chart, see attached pics)...

why are your IAT's so high...?

I tweaked your calc_pids.txt a little to make VE[g*K/kPa] show up, it seems a little high in places.

Remove the GM.DYNAIRTMP_DMA pid from your pidlist before taking another log.

See if you can hold the throttle steadier for longer, not always possible.