Virtual VE tuning

[Mark-HD]

I like this forum much better than the HPT forum, most won't respond there....

[robertway]

I just started tinkering with tuning the VE Table in my LS3 this past week, have most of the LTFTs under 4000 rpms in the =/-3% range. The real question I have is what is the definitive answer as to when the MAF is used for fueling and when the VE is. What settings in the tune determine when one is active and the other not during normal operation. I know by default as soon as you go above 4000rpms it is all MAF but what about at other times. I would like to run with both, GM has them both in there from the factory so I am assuming there is a reason for that. My MAF calibration is pretty solid with +/-2% LTFT up to about 7000hz, I haven't done WOT MAF calibration yet after starting from scratch last week.

My VE seems pretty good so far but I am having problems with cold starts that started this morning, she sounded like she had a big bump stick in her until she warmed up a little bit and the car went into closed loop.

HAs anyone here gotten the Virtual VE Tuned by either a shop or themselves?

[DSteck]

You have to fail out the MAF completely before you tune the VE table, and you can't just unplug the MAF to do that. You also need to disable VE completely before tuning the MAF. I'm not going into detail on what you need to do for accomplishing this because the answers are out there in plain daylight, and I've been traveling all day... and am consequently tired as hell!

As far as when is which one used... below 4000rpm, or whatever the high speed mode enabler is set to, both are used in conjunction with one another. Steady state operation tends to bias towards the MAF while transient operation biases towards the VE. I could say more, but bah... I want to sleep.

[robertway]

Thanks DSteck, I know how to fail each one out to be able to tune the other, MAF by setting the fail frequency to 0 and VE by setting the disable rpm real low to 200. I know some folks are running MAF only and I was for a week or so but I was noticing a lean spike and some knock during tip-in for partial throttle acceleration when cruising so I was guessing that the VE table was used under more dynamic conditions and the MAF didn't respond as well to the transient fueling needed during tip-in... hence the "Dynamic Airflow" section in HPTuners. The lean spike and the reason for it is just a guess on my part right now.

[Slowhawk]

I'm not a fan of MAF only.When the VE is tuned in right it is the best for response ect.

[DSteck]

Originally Posted by Slowhawk

I'm not a fan of MAF only.When the VE is tuned in right it is the best for response ect.

+1

It is very easy to do pure MAF in a pinch though.

[playadam]

Originally Posted by 2Tightwads

Skip the VE tune crap and run MAF only. Eliminate the VE table imo. Yes the software works to tune the virtual VE but its still alot of extra un-needed work. LS3 sensors are terribly accurate and can handle ALOT of boost!

Why take away free insurance? Look running on ve alone is blindfolding your engine and running on maf alone is like not having a spare tire...


Tune both, use both. thats why they are there.

[Josh @ Spartan LSX]

Originally Posted by 2Tightwads

Skip the VE tune crap and run MAF only. Eliminate the VE table imo. Yes the software works to tune the virtual VE but its still alot of extra un-needed work. LS3 sensors are terribly accurate and can handle ALOT of boost!

People like this guy are the reason the internet can be a bad source for information sometimes.

I highly recommend dialing in VE tables. I get cars coming in from all over the country that have been previously "tuned", but don't run the way they should. Over 50% of them just needed a VE touch-up and the car ran perfect. It's more important than a lot of people give it credit for.

[FrankT]

I re-tuned my single turbo car after finding issues with the tune by a shop in FL. IFR and PE tables were all over the place. I couldn't drive it two miles without the check engine light coming on. Also, Ford GT 500 injectors were used. Had my stock injectors opened up to 70lbs. and rescaled the stock injector table. Tuned the VE table. Then, reenabled the MAF and STFT's. Car runs great now. I used EFI Live.

[Josh @ Spartan LSX]

Originally Posted by FrankT

I re-tuned my single turbo car after finding issues with the tune by a shop in FL. IFR and PE tables were all over the place. I couldn't drive it two miles without the check engine light coming on. Also, Ford GT 500 injectors were used. Had my stock injectors opened up to 70lbs. and rescaled the stock injector table. Tuned the VE table. Then, reenabled the MAF and STFT's. Car runs great now. I used EFI Live.

Let me guess.........


Norris?

[FrankT]

Originally Posted by Damian

Let me guess.........


Norris?

Justin at J&J Performance... there I said it! Out of the three Camaro's turbo'd and tuned, mine is the only one running with the original engine. I can't believe what some shops pass off as tunes these days. If you can read and comprehend, the info is out there to do it right. That being said, I know there are quite a few good shops/ tuners out there. I just wanted to fix mine myself.

[Mike Norris]

Originally Posted by Damian

Let me guess.........


Norris?

If there is some issue, you are more then welcome to call and discuss it.

Mike Norris

[toehead93]

Do the tuners using handheld tuners do virtual PE tuning?

[camaro1]

Originally Posted by toehead93

Do the tuners using handheld tuners do virtual PE tuning?

hand held units dont do in depth tuning