VVE Tuning

[momotunes]

Hello -

Question. I'm trying to tune my VVE tables. I've tuned the MAF by logging MAF hrtz with my LC-2 wideband "EQ Ratio Error (Math). So I thought I could do the same for VVE. What I did was set up a table to match my VVE. RPM on top with MAP sensor on side both have same values as VVE and selected the parameter "EQ Ratio Error (Math)". I failed my MAF sensor, disabled long term fuel trims, DFCO, and cats overheat, disabled, copied spark tables into low spark table, and went driving. Once my engine warmed up I commanded open loop with the scanner and started logging. I'd get errors from plus 8 to -10. Id copy the data, paste special/muliply to VVE and hit that coefficients (think that's what it's called.) Then I would copy and paste that table to the other three in the drop down. I've went through this about 10 times and at this point I think I'm doing something wrong or going at this entirely wrong as nothing is improving. Maybe a percent or three if that. When I did this with MAF, about 5 drive cycles and it was perfect.

Truck I'm tunning is a 09 Silverado.

Any help would be greatly appreciated.

Thanks!

[Higgs Boson]

delete maf from scanner channel list

disable closed loop in the tune, not the scanner

raise the Count needed to hit a cell so the data gets more accurate

tune it slowly, slow pedal, 4th gear as much as possible, etc VVE takes time which is why lots of big shops set it to maf only and let it go.

[momotunes]

Thank you kindly. So looking at my tune, I can disable closed loop by raising all cells in the tab named "ECT vs. Startup ECT"? This is located in Engine - fuel - oxygen sensor - Feedback - Closed Loop Enable.
Also, under "Open Loop/ Base there is a chart named "IVT Gain Gas". Should I change all cells to "1.0"?

Lastly, is "EQ Ratio Error [Math]" the correct parameter to log in my table?

Lots of questions I know however I really appreciate the advice.

[Higgs Boson]

yes there is a table or field you can change to keep it from going into closed loop, the specific one varies depending on the OS/vehicle, you could post your tune and I/we could confirm.

EQ Ratio Error is correct if you are logging Commanded and Actual (from your wideband) and both are in lambda.

you don't need to change open loop gains, just watch commanded is at 1.0 in the scanner, but regardless, it is an error off commanded so it doesn't matter what is commanded (stoich or PE), as long as actual matches commanded then you apply the difference to airflow tables (MAF or VE)

[momotunes]

Hi -

My file is attached. I appreciate this a ton!.

Thank you,

[Higgs Boson]

yes use that table to disable, set it to 300

set your dynamic airflow to 8000 disable and 7800 re-enable

[momotunes]

Thank you! I definitely owe you for the help. I'll get started on it in the AM.

[HawkZ28]

Why 4th gear? Is it easier to hit more/wider range of cells?

[Higgs Boson]

Why 4th gear? Is it easier to hit more/wider range of cells?

or whichever is 1:1

just for consistency in your logs, mostly

[momotunes]

yes use that table to disable, set it to 300

set your dynamic airflow to 8000 disable and 7800 re-enable

Hello,

Well that didn't work:-(. It's still making short term adjustments. My understanding is that I want ltft and stft disabled correct?

Also, another dumb question. What do you think of my timing? I noticed that I'm never logging any knock but I swear I can hear it. Maybe not an I'm just noticing noisy valve train since I put on long tube headers.

[h2.4]

Why 4th gear? Is it easier to hit more/wider range of cells?

Also, with a car that is boosted, or has drag radials, or makes a decent amount of power, you can get wheel slip. The higher gears work better for me also. Slows everything down, not so touchy, and you can manipulate the throttle a little easier.

[Higgs Boson]

make sure to clear fuel trims in the scanner in case any are still hanging around in there
make sure there is not a drop down option called STFT during open loop Enabled which I didn't look for before.

[HawkZ28]

Did you set the O2 etc value to 492 or whatever the max is? There's another that comes to mind, but they're O2 readiness parameters.

I always thought more data, and steady state data the better. I've always used my 50 mile commute or a 2 lane blacktop "route" with a lot of hills and flat straights where I could fill as many cells as possible in the histo. Usually I'm ranging from 25-85 mph, changing gears, and rolling in and out of throttle up and down the hills.

[jpierro79]

you cant have your maf tuned first and you cant have a lower flow rate at a higher frequency!!! it will buck jerk everytime you hit that frequncy go lean knock ect and your losing power!!! reset your maf to stock you cant have less air at a higher frequency reading the ecu cant calculate that get your VVE inline first !!! at 7200 hertz youve got 1020lbhr and at7350 hrtz your have 816. that 20 percent drop on fuel. You need to bring up your VVE chart at whatever WOT rpm so that you dont do this. like this this is how compensate on a supercharged car for ve flow or any car with extra airflow. here first not the other way around

[Higgs Boson]

you cant have your maf tuned first and you cant have a lower flow rate at a higher frequency!!! it will buck jerk everytime you hit that frequncy go lean knock ect and your losing power!!! reset your maf to stock you cant have less air at a higher frequency reading the ecu cant calculate that get your VVE inline first !!! at 7200 hertz youve got 1020lbhr and at7350 hrtz your have 816. that 20 percent drop on fuel. You need to bring up your VVE chart at whatever WOT rpm so that you dont do this. like this this is how compensate on a supercharged car for ve flow or any car with extra airflow. here first not the other way around

i tune the MAF first on every car I tune, there is nothing wrong with that. tons of shops don't even tune the VVE at all. his maf curve looks like that if all he has tuned is part throttle and has yet to adjust WOT, but let's not make assumptions....

[momotunes]

Okay, I should start from stock tune and log lamda error to tune VVE to 2500 RPM. After I tune MAF for 2500 and up only? Do I disable VVE when doing this or do I just lower PE to 2500? Sorry for all of the dumb questions.

[momotunes]

i tune the MAF first on every car I tune, there is nothing wrong with that. tons of shops don't even tune the VVE at all. his maf curve looks like that if all he has tuned is part throttle and has yet to adjust WOT, but let's not make assumptions....

Correct. I tuned MAF only for part throttle. Honestly a little worried trying to tune WOT. The VVE is new to me so I've held back a little. Thanks for everyone's help.

[RobZL1]

You can tune maf first without issue. Just disable dynamic while tuning maf, and disable maf while tuning vve.

Make sure you change o2 readiness table as mentioned above and in both cases, or it won't go open loop.

Depending on mods, you may want to multiply your entire VVE by 15% (edit for clarity: multiply by 1.15) or so and recalculate coefficients. That will ensure you don't start out super lean if you have significantly increased airflow. Tuning part throttle will also give you some indication of how far off WOT might be, to give you an idea if you need to raise WOT areas by 10%, 15%, 20%, etc.

I would tune MAF all the way from idle to WOT, and do the same for VVE, although I think it's more important to get MAF correct for WOT.

[jpierro79]

Here's the reason i tune maf second.Its that there is chart that is called intake valve temperature multiplier and it has to to due with the intake valve temps at x rpm and you can have 2 different rpm values and two different intake valve airflow multipliers so if you tune maf first its not correct only making your vve harder to tune.
Example say at 3200 your intake valve temp read 285 degrees with a multiplier of 1.1 and you have 1/8 throttle but at 2200 rpm 1/4 throttle your intake valve temps are 245 with a multiplier of 1.2 you can have the same exact airflow with about 10 percent difference in required fuel. its just a persay example but airflow DOES NOT DICTATE CORRECT AFR you have to take into account heat and other factors. WOT yes TUNE away with maf but part throttle try to touch it as least as possible and I assure you it takes longer is more complicated but with factory like results. Also heres other thing that stinks is any time you change injectors your intake air temp multiplier is changed and so many shops tunes during summer can run lean or rich during winter. There is no simple way to tune but if you just car about max power ignore me if you want a factory drivable car please listen

[HawkZ28]

Circling back on the consistency aspect.

Wouldn't a longer highway/interstate datalog be 'better' data (assuming speeds and gear changes allow you to fill the RPM and MAP ranges from say 1200-3200 and 25-97.5kpa) with it being more data, more steady state, and the ability to roll in and out of throttle, or would a 15-20 minute drive through town with stop and go, lots of accelerating and stopping, but filling the same amount of cells with less hits and less steady state be more desirable?

Reason I ask is I can do 2 logs as mentioned, same tune, and have completely different 'pictures' of what's going on.