LFX Tuning Questions

[flatpick13]

I was looking at "Manifold Switch Closed", which is zeroed, but appears "Manifold Switch Open" is filled in. I honestly didn't realize that dropdown box for other tables was there... Like I mentioned above, very new to tuning lol.... I've found a video (Goat Rope Garage) on dialing in the MAF by creating a log table showing % difference for MAF error (using frequency) and using logged MAF error % values to do half step adjustment to the Airflow vs. Frequency table, but looks like he's tuning a V8 with an E92 ECM. Is the process with an E39 different? Where do I need to be in VCM editor to do that?

I appreciate the help! I apologize if these are dumb questions, sometimes it takes me a little bit to adjust my headspace and timing to a new concept.

[KillboyPowerhead]

Not sure if the E92 is a Gen V ECU, but the E39 and E39A are Gen V (I think, or at least they seem to function the same from what I can tell), so if looking for tuning info just make sure you're watching/reading Gen V ECU stuff if you can't find something particular about the E39.

Regarding tuning the MAF, you'll want to set up a graph to log STFT (for both banks combined; just type in "STFT" to find whatever is available; or if using two widebands you can create a custom math to average the two); units as percent; and the column axis will be Frequency/Hz, with values the same as your Airflow vs Frequency table (Engine > Airflow > General I think - don't have HP Tuners with me right now). Goat Rope Garage is good for showing how to create the graphs, copying and pasting the columns/rows, etc.

After logging you'll see an average of your STFT at each frequency/column, and then you'll want to copy and paste as percent (or percent half) these values to the Airflow vs. Frequency table. Just make sure the data you're using is from steady state driving, so you'll need to do some filtering to get rid of the data you don't want (like when shifting gears, when accelerating/decelerating, etc.). I found driving on a long, flat highway works well, if you have access to one, and set cruise control to different speeds, and going at each speed in different gears for at least a minute at a time.

Once the MAF is dialed in, like +/- 2% error in each cell, you can make a graph resembling the VVE table and adjust it similarly, but instead of using STFT or widebands just use the MAF Airflow compared to the VE Airflow; so the custom math you'd create is ((MAF - VE)/MAF), and log that vs. RPM and Pressure Ratio. Again, make sure your cams are set to 0 when tuning VVE since you can only adjust the 0/0 table directly. I'd set the cams to 0 when adjusting just the MAF too, just in case there's a difference (maybe reversion at lower RPMs?). Once the VVE is dialed in you can set the cams back to normal/whatever you want and recheck the MAF, but shouldn't make a difference.

[SiriusC1024]

I was looking at "Manifold Switch Closed", which is zeroed, but appears "Manifold Switch Open" is filled in. I honestly didn't realize that dropdown box for other tables was there... Like I mentioned above, very new to tuning lol.... I've found a video (Goat Rope Garage) on dialing in the MAF by creating a log table showing % difference for MAF error (using frequency) and using logged MAF error % values to do half step adjustment to the Airflow vs. Frequency table, but looks like he's tuning a V8 with an E92 ECM. Is the process with an E39 different? Where do I need to be in VCM editor to do that?

I appreciate the help! I apologize if these are dumb questions, sometimes it takes me a little bit to adjust my headspace and timing to a new concept.

Post a log with the mentioned channels of the tune with the MAF settings. I'll show you what to do with it.

[SiriusC1024]

Open the tune and find the MAF table. Copy the column labels.
column labels.png

Create a table in Scanner that references LTFT+STFT. Assign the column axis units. Paste the column labels.
scanner LTFT+STFT.png

Copy the scanner trims (results shown above). Paste-special into the tune MAF table.
paste special MAF.png

Extrapolate to the upper and lower bounds. I used 1.05 for top and 1.02 for bottom, based on the tail end averages.
extrapolate.png

Then smooth it out by hand or with the smoothing tool.

When you load the tune you have to go into VCM Scanner to clear LTFT's so the previous trims don't interfere.

Repeat the process until fuel trims are close.

[[email protected]]

I'm still playing with Cam Phasing and MAF adjustment...
So far I haven't seen any need with the OEM cams to vary the cam phase with barometric pressure, so all three tables are identical for each cam, and the tables have the same phase angle down each column...

Looking at the cringer (silversurfer77 on youtube) VVE-assistant, I don't see why you can't set all the cam angles to not modify the 0,0 map and then just tune the 0,0 map to your motor. Am I missing something?

Going into the tuning of this motor I was anticipating that all fueling was done in VVE, now that I've been tuning MAF I'm starting to wonder what benefit can come from touching VVE!!
Has anyone seen an improvement with tuning the VVE??

[KillboyPowerhead]

Not sure what you mean by "I don't see why you can't set all the cam angles to not modify the 0,0 map and then just tune the 0,0 map to your motor."? Haven't used Cringer's program so don't have any input there.

Even with my MAF dialed in very close (+/- 2% everywhere, if not closer to +/- 1%), if I adjusted my VVE manually by interpolating areas/zones adjacent to the ones I was more focused on (the ones hit during normal driving) in an effort to create what I thought would be smoother transitions, the engine acted kinda funky at times, mainly at lower RPM's, below 1500 or so; noticeable when accelerating from a stop, felt like there was a minor hesitation, and especially if driving at ~1400 - 1500 RPM and then relatively quickly going to > 50% throttle (more so in 3rd hear or higher), felt like the engine was lugging, and if I kept pushing the pedal the RPMs would suddenly jump up and the throttle would quickly open a bunch more. After readjusting the VVE using logged data and just calculating coefficients, no manual intervention, the engine acted much more smoothly. Seems as if the VVE has an effect on some torque calculations (throttle operation), not to mention the fuel delivery during transients/throttle changes.

So whether or not you need to change the VVE of the stock tune with just minor mods, or maybe even Mace cams, not sure, but if done correctly I can't see it hurting anything, and at the moment my engine seems to run pretty smooth. Also makes me feel better when I see that my MAF Airflow is within a few % of VE Airflow, compared to over 20% difference like it was after I initially installed the Mace cams There's definitely a noticeable effect if adjusted improperly

[[email protected]]

thanks for the feedback!

[flatpick13]

@SiriusC1024 Thank you! Just set up the tables, will run some logs as soon as I get a chance (likely this evening) and start incrementing the tune. The step by step with pictures is very helpful!

[[email protected]]

Alright, here's what I was referring to...
The VVE table is generated from a bunch of constants, these constants in the "Speed Density" tab are 2D-quadratic curve fitting coefficients.... Which doesn't mean much other than to say that you can't directly modify the values in the VVE Table, you can change values in the VVE table, press the "calculate coefficients" button, the new coefficients are written into the Speed Density tab and the VVE table now represents the curve fit of these new coefficients....

Daniel (cringer, silversurfer77) has written a tool to calculate these coefficients and view the changes. His tool can handle tuning at varying positions of both cams, but the amount of data logging required to accomplish this is mind boggling, I can't see that anyone could do this without lots of time on a mustang dyno.

I confirmed last night that if you make every coefficient table with the word "cam" zeroed out, you will end up with the 0,0 cam position table being replicated for every combination of intake and exhaust cam
001-VVE.png
002-VVE.png

For me with the OEM cams I'm not finding any need to modify the cam phasing with respect to load or barometric pressure, so having the VVE remain constant no matter the cam position should work fine, the 0,0 VVE table simply represents the VE of my motor.
This is what my cam phasing looks like:
003-VVE.png
If the MACE cams need to have a wider LSA at low barometric pressure for example, you could still accomplish this. You should be able to zero out the VVE cam coefficients, tune VVE at 0,0 cam position in the zones that will vary with barometric pressure, then change to the low barometric pressure cam positions, tune those, and repeat at the high barometric pressure positions by using Daniel's tool tune the calculate the coefficients in the zones where the cam angle differs with barometric pressure.... This will probably be even more difficult in the real world than it sounds.

I'll load up this configuration with the VVE coefficients and see how it runs, then I'll start figuring out how to tune the VVE and move on to that.

[KillboyPowerhead]

I'm assuming when you say load you're referring to pressure ratio, or do you mean airmass? And by barometric pressure you mean the low/med/high tables?

I don't understand the reason for different baro tables either, although where I live I'm always in the high table so I haven't thought about it much. The idea behind adjusting the cams is to reduce pumping losses for fuel economy and create an EGR effect (and consequently eliminate the EGR valve) to reduce emissions at cruising; and maximize airflow/volumetric efficiency/power for high demand driving/performance throughout the whole RPM range; but not sure how atmospheric pressure affects any of these - if at a given air pressure/density you're achieving maximum volumetric efficiency, for example (let's say your cams are set perfectly), wouldn't you still be achieving max volumetric efficiency at a different air pressure/density?

Regarding adjusting cams for airmass, I too don't see the reason to have different cam settings for different airmasses other than what I mentioned earlier (for fuel economy at your normal cruising RPMs/airmasses, and for performance elsewhere, blending/smoothing the two sections together), because if you adjust the cams and airflow/airmass increases, for example, and now the ECU is looking at the next row, you'd still want to be at that particular cam setting.

Having a different VVE table for every cam position combo makes sense though. Each cell/number in the VVE table represents the amount of air in mg, and by changing the cams you'll get more or less air for a given pressure ratio/throttle position at a given RPM. Regarding adjusting a given VVE table, my plan was to get the base table dialed in with both cams set to 0; figure out what cam settings work best for cruising (figured I'd go by Injector Flow Rate to see what settings use the least fuel); figure out the best settings for WOT using MAF airflow/cylinder airmass; then check/recheck the accuracy of the VVE table for those cam positions; so only dealing with a few different combos rather than hundreds, modifying them directly via the constants if needed. To dial in the VVE table I found it best to just dial in the MAF and then make VE Airflow match MAF Airflow, so will do this once the cams are where I want them, just like I did/am doing with the cams at 0.

[[email protected]]

I'm assuming when you say load you're referring to pressure ratio, or do you mean airmass? And by barometric pressure you mean the low/med/high tables?

Yes, and yes.
Pressure ratio and air mass are different concepts describing the same thing. The airmass perspective makes fueling easier to rationalize, but pressure gives more granularity to spark mapping.

I don't understand the reason for different baro tables either, although where I live I'm always in the high table so I haven't thought about it much. The idea behind adjusting the cams is to reduce pumping losses for fuel economy and create an EGR effect (and consequently eliminate the EGR valve) to reduce emissions at cruising; and maximize airflow/volumetric efficiency/power for high demand driving/performance throughout the whole RPM range; but not sure how atmospheric pressure affects any of these - if at a given air pressure/density you're achieving maximum volumetric efficiency, for example (let's say your cams are set perfectly), wouldn't you still be achieving max volumetric efficiency at a different air pressure/density?

You make a great point, I assumed this meant manifold pressure, but I think you're right, it probably does mean elevation. The medium threshold lines up with denver's elevation.
It's not all about VE though, MAF double counting during overlap can artificially inflate VE, dynamic compression plays into both power and efficiency as does expansion ratio.
The right way to optimize is on the dyno. Give the motor a voice and listen to what it wants.....

Regarding adjusting cams for airmass, I too don't see the reason to have different cam settings for different airmasses other than what I mentioned earlier (for fuel economy at your normal cruising RPMs/airmasses, and for performance elsewhere, blending/smoothing the two sections together), because if you adjust the cams and airflow/airmass increases, for example, and now the ECU is looking at the next row, you'd still want to be at that particular cam setting.

I think it's an emissions requirement. In my experience with a Gen V LT and this LFX, best fuel economy is achieved at the best performing cam setting.
The best performing setting has been worlds different than the OEM setting.

Having a different VVE table for every cam position combo makes sense though. Each cell/number in the VVE table represents the amount of air in mg, and by changing the cams you'll get more or less air for a given pressure ratio/throttle position at a given RPM. Regarding adjusting a given VVE table, my plan was to get the base table dialed in with both cams set to 0; figure out what cam settings work best for cruising (figured I'd go by Injector Flow Rate to see what settings use the least fuel); figure out the best settings for WOT using MAF airflow/cylinder airmass; then check/recheck the accuracy of the VVE table for those cam positions; so only dealing with a few different combos rather than hundreds, modifying them directly via the constants if needed. To dial in the VVE table I found it best to just dial in the MAF and then make VE Airflow match MAF Airflow, so will do this once the cams are where I want them, just like I did/am doing with the cams at 0.

Sounds interesting, please report back.

[[email protected]]

Went for a quick drive with the coefficients zereod to make all VVE the same, what a difference for the better!
Shift points went back to where they should be, so clearly the transmission shift points look at VVE to determine load and the whacky VVEs (many are negative) outside of 0,0 is what was causing the short-shifting that I've been noticing lately.
Transients also seem to be much snappier, but this will need some more time to confirm.

Now I'll have to figure out how to setup logging and get started with tuning VVE...

[SiriusC1024]

Transmission logic references the torque model, that references dynamic airflow, which consists of MAF and VVE, and commanded spark compared to MBT.

Tune the torque model.

[[email protected]]

Tune the torque model.

Can you suggest a reference on how to tune the torque model?

[KillboyPowerhead]

I'd also be interested in some sort of guide on tuning Virtual Torque. Found these two threads:

https://forum.hptuners.com/showthrea...virtual+torque
https://forum.hptuners.com/showthrea...-torque-tables

Looks like you're just logging Delivered Engine Torque and setting up tables to replicate the VT tables, and making the VT tables the same as Delivered Engine Torque. But this is about as much detail as I have found on the subject.

[flatpick13]

@SiriusC1024 I did a few increments on the MAF vs. Output Freq, I attached the last run's log, fuel trims look closer but are still pretty far off on the outside, primarily higher RPM. I tried to do logs from steady state as much as possible during cruising, but not a lot of straight/flat roads near me. Do I need to do more runs across the whole RPM range for the MAF, or should I just stick with cruises and use smoothing then tune top-end WOT type driving with Speed Density? I also didn't understand the instruction on extrapolating between 1.02 and 1.05... Not sure if I missed something in updating these tunes but saved them in steps if I need to redo anything. I'm still getting throttle hang, although this seems to be helping a little, should I move to tuning Speed Density after MAF?

Thanks again for the help!

[gtstorey]

You need to set up filters to remove any data that isn't valid and do longer drives.

[SiriusC1024]

Don't really need filters with fuel trims.

Post the tune that log came from.

[flatpick13]

You need to set up filters to remove any data that isn't valid and do longer drives.

How do I set up filters and what data isn't valid...? The log is from a short stint in a longer drive, per comments above I was trying to get to an area I could stay relatively steady state cruising. I do have several logs from longer drives that include start/stop, gear changes, etc. from the same tune if those are more helpful. I'm new to this so happy for any tips that help me get to a better running engine.

Don't really need filters with fuel trims.

Post the tune that log came from.

Attached the tune.

[SiriusC1024]

Do more varied throttle movements on the next log. Not more rapid, though.

Clear LTFT's.