maf tune/no open loop nice flat 12.5 fuel trim

[mstrfdsstr]

Is this a problem running in maf tune only?

[mstrfdsstr]

Turned off the ve table all of a sudden i have plenty of top end the maf was tuned by a pro oyea no more fluttering at 2100 rpm and other part trottel.I would imagine this will cange ahd I will need speed density with a cam and nitrous.

[E85LSX]

There's no problem running MAF only, Ive been doing it for a while to. Some people believe that the car has more response with both VE and MAF working but thats debatable.

[mstrfdsstr]

definatly not more responsive with the ve table ran a 12.6@111 1.95 on drag radials if only I could get off the line 12.2 possable

[Alvin@PCMofNC]

I prefer both the VE and MAF be tune in conjunction whenever is possible. A member Bluecat released a very powerful tool for VE tuning on HPtuners forum. We use it almost daily.

[2Tightwads]

Ve tuning is wasted extra work on the LS3 that is not neccesary. Run MAF only. Go read up more on it on HpTuners.com/forum.

[JANNETTYRACING]

Originally Posted by 2Tightwads

Ve tuning is wasted extra work on the LS3 that is not neccesary. Run MAF only. Go read up more on it on HpTuners.com/forum.

I mean you no personal disrespect, but This comment sounds foolish to anyone who has any real experience tuning GM Cars for the simple fact the the maf is used during steady state and the computer uses VE for throttle transitions.

If they are both tuned properly the car will run better than ever.

The VE table is a very important part of the tune.

I will also note that VE tables can usually be left alone as long as the engine has not been altered with bigger heads and Camshaft or Supercharger, but when these are changed out, VE tuning is necessary.

Take the information for what it is worth.

[E85LSX]

Originally Posted by JANNETTYRACING

I mean you no personal disrespect, but This comment sounds foolish to anyone who has any real experience tuning GM Cars for the simple fact the the maf is used during steady state and the computer uses VE for throttle transitions.

I have to respectfully disagree with this statement. The MAF is not only used in steady state and the VE is not used to determine fueling during throttle transitions. Both the MAF and VE do the same thing, they estimate the airflow entering the engine, the VE is usually checking the the values from the MAF so there is some redundancy in the system in case the MAF were to fail. On the stock tune the VE is ignored above 4,000RPM and it uses MAF only. Do you believe that when above 4,000 rpm there is no longer a need for any transient fueling due to throttle transitions? or maybe there is another set of parameters that account for throttle transitions.

During throttle transitions the transient fuel calculations account for the changing impact factors and evaporation of fuel from the intake and valves. There is always a film of fuel on the intake valve since the injectors spray the back of the intake valves to keep them cool, the trick is keeping this film constant through changing pressures and air velocitys in orded to keep fuel delivery precise. It is the transient fuel calculations job to handle this not the VE tables.


I'm not sure if the car will run better with both the MAF and SD determining the total airflow but I am planning to experiment with this myself and I will definitely post my findings. Supposedly this used to be the case with older less sensitive MAF sensors and slower computers but today the MAF sensors and computers are so accurate it makes no difference. We'll see. . .

[JANNETTYRACING]

Originally Posted by E85LSX

I have to respectfully disagree with this statement. The MAF is not only used in steady state and the VE is not used to determine fueling during throttle transitions. Both the MAF and VE do the same thing, they estimate the airflow entering the engine, the VE is usually checking the the values from the MAF so there is some redundancy in the system in case the MAF were to fail. On the stock tune the VE is ignored above 4,000RPM and it uses MAF only. Do you believe that when above 4,000 rpm there is no longer a need for any transient fueling due to throttle transitions? or maybe there is another set of parameters that account for throttle transitions.

During throttle transitions the transient fuel calculations account for the changing impact factors and evaporation of fuel from the intake and valves. There is always a film of fuel on the intake valve since the injectors spray the back of the intake valves to keep them cool, the trick is keeping this film constant through changing pressures and air velocitys in orded to keep fuel delivery precise. It is the transient fuel calculations job to handle this not the VE tables.


I'm not sure if the car will run better with both the MAF and SD determining the total airflow but I am planning to experiment with this myself and I will definitely post my findings. Supposedly this used to be the case with older less sensitive MAF sensors and slower computers but today the MAF sensors and computers are so accurate it makes no difference. We'll see. . .

I guess my point was overlooked, I just tried to keep it simple, the Maf is most active and VE is referenced during quick throttle transitions, especially at engine speeds below 4000 rpm, because of the what I call the slinky affect.

I did not want to get in to trasinent fueling too complicated to explain.

The point was VE tuning is necessary when a change to Hard parts affect VE.

I have tuned all different ways, you can get good results either way for most apps, but aren't we here to find Perfection?

I do agree with your technical explaination.

[99-LS1-SS]

I'm running MAF only on my G8 GXP (LS3) and I haven't had any issues.

[Camar0wn3d]

Originally Posted by JANNETTYRACING

I guess my point was overlooked, I just tried to keep it simple, the Maf is most active and VE is referenced during quick throttle transitions, especially at engine speeds below 4000 rpm, because of the what I call the slinky affect.

I did not want to get in to trasinent fueling too complicated to explain.

The point was VE tuning is necessary when a change to Hard parts affect VE.

I have tuned all different ways, you can get good results either way for most apps, but aren't we here to find Perfection?

I do agree with your technical explaination.

So do you think MAF-only tuning would be okay without touching the VE if my only mods are gonna be the Vararam Tune-only Intake and Headers? Sounds like MAF only tuning is the way for me to go until I get a cam.

Also, for HPTuners, what should I scan to see the feedback? (I'm guessing create a histogram with MAF Frequency vs. LTFT?)

[E85LSX]

Originally Posted by wh0rsep0wer

So do you think MAF-only tuning would be okay without touching the VE if my only mods are gonna be the Vararam Tune-only Intake and Headers? Sounds like MAF only tuning is the way for me to go until I get a cam.

Also, for HPTuners, what should I scan to see the feedback? (I'm guessing create a histogram with MAF Frequency vs. LTFT?)

MAF only will work great with those two mods. The size of the cam will dictate whether or not VE tunning will be nessacary. A very large cam will be hard to tune MAF only. With that being said I just tuned my car MAF only after installing a cam, the specs are 230's duration on a 112lsa.

[JANNETTYRACING]

Originally Posted by wh0rsep0wer

So do you think MAF-only tuning would be okay without touching the VE if my only mods are gonna be the Vararam Tune-only Intake and Headers? Sounds like MAF only tuning is the way for me to go until I get a cam.

Also, for HPTuners, what should I scan to see the feedback? (I'm guessing create a histogram with MAF Frequency vs. LTFT?)

In most cases Maf tuning works fantastic.

Ted.

[Meister@Torq]

Turning off the VE table is fine. Tuning the MAF is much better