Normal for VVE to be so far off?

[sixt9stang]

I have been working on the tune on my car again with the WB sensor and went through the MAF and it was also pretty rich down low. After going through the MAF a bit it is definitely running better than the last time I tuned the MAF with just STFT+LTFT. Now I am working on the VVE and this is from my first scan.
vve_OL_1.png

For reference this is a G8 6.0 without DOD and has cam (219/223 112 LSA), also has long tubes. Kind of just looking for a sanity check since I was under the impression that I would be running more lean, not rich after the cam and long tubes.

Here is the scan too but it is kind of long.
vve_OL1.hpl

[Kfred 513]

I recently started working on my tune after installing headers. My car was a few percent lean after the header install. I needed to richen up most of the table. Are you on E85 and maybe the ethanol content is lower now than when it was the first time you tuned?

Edit: Just realized you have 14.68 set to stoich so i guess you arent on E85. Not sure what would cause it to be rich in that case.

[sixt9stang]

See that is what I thought also. That I would be more lean. I did what I considered a final VVE tune tonight with the following for my averages:
VVE_OL_Avg.png

I smoothed the graph a bit but didn't touch it too much. So that was the Average EQ error.

This is the high, or leanest that it was:
VVE_High.png

So I was starting to wonder if I should call it good and turn back on the MAF and O2 sensors or if I should actually richen everything up.

And yes. Just normal gas. I have been running the 92 octane premium from Costco.


Edit: was going to attach the log from today but it was too large. I will have to look at my other log that is attached to the first post but I am trying to figure out why the car would go rich at something like 3200 rpm. Here is a screenshot. Any ideas?
VVE_Richat3200.png
On the Chart you can see that it has been at 3200 RPM for a few seconds and then all of a sudden it goes rich. Looks like it coincides when I start to let off the gas. Maybe I should change my filter more to filter out that more. Right now the filter is: [2111.156.slope(200)]<5 AND [2111.156.slope(-200)]<5 for controlling throttle changes and plus this: [6310]<7 OR ([6310]<15 AND [6310]>7) for the Fuel trim cells.

[DGS]

i see o2 inputs even though you are in open loop. I think you still need to disable o2's in your tune.your charts show eq error. i don't believe you should be correcting for error. the wideband needs no correction. can't see any of your charts and how the are set up or a log or a tune.

[sixt9stang]

There is an initial log in the first post and here is another one.
vve_OL2.hpl


I also notice that the O2 sensors are reading but the Fuel System status is OL so it should be in Open Loop.

Here is the tune that I made after this run: VVE_OL_2.hpt

I am using the EQ error to correct the VVE table. I am not trying to correct the wideband. Maybe I misunderstood your question though.

For the EQ Err graph I am using this filter:
[13.114]>1 AND [2111.156.slope(200)]<5 AND [2111.156.slope(-200)]<5 AND [6310]<7 OR ([6310]<15 AND [6310]>7)

Thanks for looking!

[sixt9stang]

Do you think even though I have the tune in Open Loop that changes are still being made from the STFT's? Should I max out the O2 Readiness ECT to disable STFT?

[DGS]

Yes, you don't want any o2/trim inputs. If there is activity on the charts, it's altering the results. Also fully warmed up and reset fuel trims before logging.

[BBA]

With a cam, VVE will be way off. Most tuners cheat doing the VVE tuning by simply lowering the dynamic airflow rpm to a below idle rpm, that way you basically run a maf only tune. (The right way is to actually tune VVE).

[sixt9stang]

I will do it again after making changes to the tune to completely disable the O2 values.

With a cam, VVE will be way off. Most tuners cheat doing the VVE tuning by simply lowering the dynamic airflow rpm to a below idle rpm, that way you basically run a maf only tune. (The right way is to actually tune VVE).

I know it would be off. I just thought it would be off the other way. That I would be running more lean since I would be bringing in more air. I know a lot of people tune MAF only but I like learning and wanted to do both. I am going to try the VVE some more with the STFT's not running and see what happens. If that makes a change I am probably going to do the MAF vs EQ error with the STFT's also disabled.

Hoping to make another run today and will post results.

[sixt9stang]

Had a chance to go for a drive after disabling the STFT's and this is my EQ error now:
vve_no_stft.png

Looks like I have some work to do. I may put the VVE back to stock and then start over from there.

Here is the log. vve_ol_nostft1.hpl

Thanks for the help and suggestions. STFT's must have been still making changes.

[sevinn]

Consider the fact that a larger cam is less efficient down low meaning the engine is a less efficient air pump in that same range. Without touching fueling from stock it will be rich.

If your maf is dialed in and it drives fine, you can back calculate vve based off of dynamic airflow or maf airflow to get it in the ballpark.

[sixt9stang]

I was starting to wonder about it just not being as efficient in the lower rpm range too. How do you calculate the vve from dynamic airflow or maf? Sounds like that might be a quick way to get the vve close. Thanks!

[sevinn]

Check this post out. You may have to correct some of the variables for newer versions of HPT but the gist is the same. You just need to create a math parameter and log the correct pids.

https://forum.hptuners.com/showthrea...l=1#post449664

[sixt9stang]

I have seen that thread before but it was over my head. I now understand how the math and pids work so I should be able to figure it out. Only question would be do I just plot one of the math parameters on the same graph that I have been plotting the EQ error? Also, I am guessing that I do not need to be running an SD tune in order to do it this way? Sorry for all the questions.

[sevinn]

If you use dynamic airflow or maf airflow you can have the vehicle running maf only while logging this it doesn't matter, and yes you would just log the math parameter over the same rpm and kpa range that you'd be logging eq error or fuel trims via VVE with.

[sixt9stang]

Awesome! Thanks for the help! I love learning this stuff.