Final Verdict for VE on SC V6 ??????

[John_F]

Whats the final verdict on VE tuning for SC 3800 vehicles? I've read all kinds of conflicting information.
1. VE table is only referenced for a MAF failure ??
2. If VE changes are made and we use the MAF the changes are meaningless ??
3. VE changes are referenced even when running the MAF ??
4. I over run the VE table anyways, so should I even bother ??
5. Over running the VE table makes VE table worthless to me ?? or will tuning it for the lower ranges at least help there ??

Help ......

[Bill@HPTuners]

I was able to pick up 7 tenths with tuning alone without touching the ve table and from what I've heard its not used unless the maf fails.

[John_F]

Thanks foff667, thats just what I thought. Now, how about idle ? Would changing the VE table just for idle have any affect ?? I doubt it, but it cant hurt to ask anyways
I usually skew the MAF for that but dont really like doing it unless there's no other way.

Any one else have info to share on VE with SC V6 ?

[Bill@HPTuners]

havent done any cammed v6's yet to be completely honest so im not sure about the best way to adjust idle other then the commanded idle table honestly.

[animuL]

Where does HPT advise to not use VE tuning on a V6?

[animuL]

I haven't been able to find anywhere that HPTuners advises to not tune in VE tables on the V6. Its not uncommon to see fuel trims other than 0% at WOT, and having this not at 0% is especially dangerous on the supercharged 3.8 because of its hypereu-chipped-it pistons. Making sure you have a properly tuned VE table will keep those WOT fuel trims at 0% and keep the pistons whole.

[Bill@HPTuners]

http://www.hptuners.com/forum/showth...&highlight=maf
http://www.hptuners.com/forum/showpo...67&postcount=8

[animuL]

I think Chris is wrong. Simple way to prove it: Reset fuel trims and do a nice log file. Then move all the VE numbers to say 120 and reset fuel trims and do a similar log. If hes right then all the fuel trims and wideband readings will be about the same from one log to the next. If hes wrong then they will differ. Setting them all to 120 would normally command a lot more fuel, but if hes right and it is never used when the MAF is working, then it won't make any difference. I'll try and get out there to put this to rest. Does anyone disagree with the logic of a test like this?

[iGoRa]

No , I think you are right.

[John_F]

Thats exactly why I made this post to begin with. Someone needs to get their S**T together and give us a straight answer.

[animuL]

I'd be happy to test this out, either result is fine with me, it would just be nice to set this to rest. I'll do the test at my next opportunity (hopefully this weekend).

[John_F]

I really hope it does work Tom. With the wideband all I'd have to do is use the AFR Error histogram. Its plug and play basically.
It would be nice to have a somewhat normal looking IFR table and MAF table.

But we've been told that it doesn't work for V6, so I never bothered with it.
Hopefully it does work.

[iGoRa]

I have mine VE dialed in with wideband.

[TheDastardlyDuo]

Not having much experience with the 3800's, I dont know how much this will way in, but I had one car on the dyno (Mustand MD-1100), and the VE table histogram was very rich showing about -9 for the LTFT's across the board. The car had a ported S/C, Cam, Converter, Off road pipe and was seeing about 13psi. Car was also dumping fuel on de acceleration causing it to pop and backfire. Adjusting the VE to get the LTFT's closer to 0- -4, got rid of this. Final resutls were overall better driveability as well.

[Chris@HPTuners]

guys, it works like this in the code:

1. the MAF is used all the time in normal conditions ie. P0101, 102, 103 not set.

2. there is an option thats sets what the PCM uses for airflow if the MAF fails, it has a few different options: Zero, Speed Density or MAF Estimation. Usually this is set to Speed Density. MAF estimation is similar to Alpha-N style tuning.

3. it looks like the VE can be calibrated to be used during transients, but this isn't done in any cals i have seen. Possibly GM has never tested that code or never found a need for it.

A simple test would be to set your VE table to zero and see if the car still runs.

Hope that helps,

Chris...

[slow6]

I have mine VE dialed in with wideband.

are you sure? how did you tune yours?
did you use Gary's writeup? aka devildogg9999

[viper04af]

guys, it works like this in the code:

1. the MAF is used all the time in normal conditions ie. P0101, 102, 103 not set.

2. there is an option thats sets what the PCM uses for airflow if the MAF fails, it has a few different options: Zero, Speed Density or MAF Estimation. Usually this is set to Speed Density. MAF estimation is similar to Alpha-N style tuning.

3. it looks like the VE can be calibrated to be used during transients, but this isn't done in any cals i have seen. Possibly GM has never tested that code or never found a need for it.

A simple test would be to set your VE table to zero and see if the car still runs.

Hope that helps,

Chris...

stock 1997 M5 cars come with 80 in every VE cell so i dont think its used

[animuL]

I set my VE table to 100 and the fuel trims changed significantly on back to back log files that were almost identical to each other and after resetting the fuel trims before each test. As easy as it is to dial in, why not just do it?

[viper04af]

I set my VE table to 100 and the fuel trims changed significantly on back to back log files that were almost identical to each other and after resetting the fuel trims before each test. As easy as it is to dial in, why not just do it?

are you using a WB ?

[iGoRa]

i did