gtpsleeper
New member
probably a stupid question... but should i be paying more attention to my LTFT or the STFT when doing my ve tune?
ve tune
- Thread starter gtpsleeper
- Start date
Juanmiguel
New member
You're supposed to use both for VE tune. I don't recommend doing it though.
gtpsleeper
New member
the more ive read hp tuners the more it makes me wanna ve tune to get comfortable with the tuner... plus since i cant make a "maf" histogram while scanning itll take me alot longer anyway....
im still brand new to this so i dont wanna screw it up...
im still brand new to this so i dont wanna screw it up...
Z34Phoenix
Florida Tuner
if your new to tuning i would stay away from messing with the VE table.
the order i feel people need to experiment with is:
-PE A/F
-MAF table
-PE A/F by time
-Spark table
-VE tune
the thing is as you go down the list the changes become more and more specific. it is like changing from a paint roller down to a small paint brush down to a tooth pick!
when you work down your tune to adjust AF (from a wide band only as the stock narrow band doesnt work well enough) you can go down the list to level the AF out.
the order i feel people need to experiment with is:
-PE A/F
-MAF table
-PE A/F by time
-Spark table
-VE tune
the thing is as you go down the list the changes become more and more specific. it is like changing from a paint roller down to a small paint brush down to a tooth pick!
when you work down your tune to adjust AF (from a wide band only as the stock narrow band doesnt work well enough) you can go down the list to level the AF out.
TheOtherNick
The mod from over yonder
You should fix your maf table first so you lock in a 0 fuel trims WOT. I have never done a Ve tune on my car never saw the point.
Z34Phoenix
Florida Tuner
Yes Maf can get you to have 0% trims. but if your tuning for specific Air Fuel ratio you may have to dive into the VE to make the specific adjustments to get the AFR where you want.
Z34Phoenix
Florida Tuner
it deff works on my 96 Z34 works on my friends 97 Z34 and my other friends 2002 GTP we all use wide bands to get true data. Im not sure your tuning experience 01gpgt01, but i have seen the raw data. It works. the only thing i can say in your defense is that some OSID's respond differently. i havent read up on it lately but we believed it to be something in a table that the powrtuner could not access.
Yes the VE is used when the MAF fails. But that doesnt mean it isnt used as a base line when the MAF is working. MAF covers just air flow not pressure. lets say at 4000rpm you are at a MAF of 6200hz. Depending on pressure outside/temp/pulley/ect you could be at 90kpa or 110kpa both are different cells on the VE table. you could have Kr and be lean at 110 kpa and rich at 90 kpa. you can fine tune your AF by adjusting the VE table to balance this.
If your way works for you and your Happy. GREAT. I have been tuning this way and seen the results for 7 years now. Your not going to sway my point of view. I Feel the OP had a valid question and i am giving valuable information that could help.
I may have gone off topic for him a bit and i apologize. The original question was what to pay attention too...LTFT or STFT during a VE tune. as with all tuning you really need to watch both even when MAF tuning as if the STFT are not 0 or close to it then the LTFT's are not 100% accurate and you should wait till the trims are learned and the STFT are zero.
to go further with the question. A specific VE tune really isnt nessesary unless you have done drastic chagnes to the engine such as a cam, ported blower, TB, headers, rockers. I feel it is very important to do the VE tune because if the MAF were to fail! then your VE better be on point. otherwise one failure will lead to the chance of major damage to the engine.
Yes the VE is used when the MAF fails. But that doesnt mean it isnt used as a base line when the MAF is working. MAF covers just air flow not pressure. lets say at 4000rpm you are at a MAF of 6200hz. Depending on pressure outside/temp/pulley/ect you could be at 90kpa or 110kpa both are different cells on the VE table. you could have Kr and be lean at 110 kpa and rich at 90 kpa. you can fine tune your AF by adjusting the VE table to balance this.
If your way works for you and your Happy. GREAT. I have been tuning this way and seen the results for 7 years now. Your not going to sway my point of view. I Feel the OP had a valid question and i am giving valuable information that could help.
I may have gone off topic for him a bit and i apologize. The original question was what to pay attention too...LTFT or STFT during a VE tune. as with all tuning you really need to watch both even when MAF tuning as if the STFT are not 0 or close to it then the LTFT's are not 100% accurate and you should wait till the trims are learned and the STFT are zero.
to go further with the question. A specific VE tune really isnt nessesary unless you have done drastic chagnes to the engine such as a cam, ported blower, TB, headers, rockers. I feel it is very important to do the VE tune because if the MAF were to fail! then your VE better be on point. otherwise one failure will lead to the chance of major damage to the engine.
01gpgt01
New member
My tuning experience is about 6 years on this platform, Ive owned my GT since 04. 0 out a VE table and tell me what happens? NOTHING lol. I use a wideband, Any one with common sense knows the narrow bands a crap shoot in PE.The maf sensor does a fine job of regulating fueling for different air conditions hence why HZ ratings drop and go up from summer to winter and air density changes. I cant comment on the 3.4's or any other line up, But I do know GP's rather well. Again I must say, dont waste your time on the VE table are the 3.4's even maf and map aswell?
your experience seems based on 3.4's, and one or two recants on the 3800. You will probably be the only one on this board that thinks VE tune does anything. But I wont argue it, Let the original poster learn for himself.
your experience seems based on 3.4's, and one or two recants on the 3800. You will probably be the only one on this board that thinks VE tune does anything. But I wont argue it, Let the original poster learn for himself.
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Z34Phoenix
Florida Tuner
if we are throwing history around... i have had my Z since 2001. i have had my tuner since 2004. I have had a great deal of experience with my 3.4L Yes. but the majority of my tuning has been for people in the florida area near me. like said GTP's riveira and mc's. I have tuned well over 20 different cars with a few of them being friends that i tuned on a regular basis.
If im the only one on the board that "Knows" VE tuning helps then GREAT. Everyone now knows who to bring their tuning questions to. a person that has the experience and understanding to complete a full tune. and not someone that settles with well this is close enough.
if you see no benefit in it great! Some people dont believe in higher education either. how many of these have you even tried anything with the VE? For someone who says they have been tuning for 6 years i am disappointed. one of my good friends has had his for even longer then i have and he still doesn't understand much more then minor maf tuning using eddies program.
and just to stop the bad information going out in this thread. the MAF does nothing to regulate fueling for different air conditions. the only thing it does is calculate Air Flow into the engine. One glance at the Spark Timing table will show that MAP is what is adjusting your car for different conditions.
As a final warning to anyone reading VE is important in making a complete tune. something that just works then dont worry about it. but i feel for the people that spend the time, effort and money into major modifications to these cars it is a major mistake to do an incomplete tune. if your MAF were ever to fail and there isnt an updated VE the engine can have serious KR. and do serious damage. I just dont know why someone would risk that? GM had "fail safes" in place. we have access to adjust these to still work. I say use them.
the information is out there. Jerry note book i believe covered all the reasons behind doing a VE tune. Ah sorry i found it.... it is on the DHP forum. here is the complete quote:
" The important concept to grasp here is that the VE table is used in both open and closed loop modes.
What is not so obvious is that the VE table, when programmed correctly, will result in a 14.7 A/F ratio with no closed loop (LTFT) or open loop correction taking place. In other words, this table provides a baseline that tells the PCM where 14.7 A/F ratio is so that other A/F ratios can be commanded and the PCM will be at the desired AFR. When this table is adjusted correctly, the engine runs the smoothest, not because the engine is running at 14.7 necessarily, but because all other ratios depend on this table being accurate. If this table is off, the closed loop LTFT will correct the A/F ratio back to 14.7 to a degree. If this table is way off, the closed loop LTFT can’t compensate and the engine may not run period." Tuner_Rev_1.0.9h webracin Board Message
Enjoy the Read All
If im the only one on the board that "Knows" VE tuning helps then GREAT. Everyone now knows who to bring their tuning questions to. a person that has the experience and understanding to complete a full tune. and not someone that settles with well this is close enough.
if you see no benefit in it great! Some people dont believe in higher education either. how many of these have you even tried anything with the VE? For someone who says they have been tuning for 6 years i am disappointed. one of my good friends has had his for even longer then i have and he still doesn't understand much more then minor maf tuning using eddies program.
and just to stop the bad information going out in this thread. the MAF does nothing to regulate fueling for different air conditions. the only thing it does is calculate Air Flow into the engine. One glance at the Spark Timing table will show that MAP is what is adjusting your car for different conditions.
As a final warning to anyone reading VE is important in making a complete tune. something that just works then dont worry about it. but i feel for the people that spend the time, effort and money into major modifications to these cars it is a major mistake to do an incomplete tune. if your MAF were ever to fail and there isnt an updated VE the engine can have serious KR. and do serious damage. I just dont know why someone would risk that? GM had "fail safes" in place. we have access to adjust these to still work. I say use them.
the information is out there. Jerry note book i believe covered all the reasons behind doing a VE tune. Ah sorry i found it.... it is on the DHP forum. here is the complete quote:
" The important concept to grasp here is that the VE table is used in both open and closed loop modes.
What is not so obvious is that the VE table, when programmed correctly, will result in a 14.7 A/F ratio with no closed loop (LTFT) or open loop correction taking place. In other words, this table provides a baseline that tells the PCM where 14.7 A/F ratio is so that other A/F ratios can be commanded and the PCM will be at the desired AFR. When this table is adjusted correctly, the engine runs the smoothest, not because the engine is running at 14.7 necessarily, but because all other ratios depend on this table being accurate. If this table is off, the closed loop LTFT will correct the A/F ratio back to 14.7 to a degree. If this table is way off, the closed loop LTFT can’t compensate and the engine may not run period." Tuner_Rev_1.0.9h webracin Board Message
Enjoy the Read All
01gpgt01
New member
The maf does regulate fueling in different conditions. Why is it in the winter people hit higher HZ numbers? Because the airs denser! Denser air is cooler, and it pulls more heat out of the maf hotwire then air of less density. If all your information was true then Maf numbers would be consistent if it didnt make Density adjustments. Sorry its just not true! But hey what ever tickles your pickle. keep wasting everyone's time LOL.
If the table is way off the car wont start? A few years back I flashed my VE table to all zeros as a test, the car ran fine lol
If the table is way off the car wont start? A few years back I flashed my VE table to all zeros as a test, the car ran fine lol
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Z34Phoenix
Florida Tuner
If u were the least bit educated you would know that is a quote from one of the people who first began tuning these cars. Direct from the Powrtuner site. So far I have provided data and quotes supporting my side. What do you have?
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01gpgt01
New member
Atleast bit educated? LOL. Stick to modding 3.4 montes with hardly any mods. Im sure your excellent with them lol. That whole 1 percent you added to maf Hz made all the differance lol. Im educated enough to have knowledge of how the maf works, and not just use other peoples thoughts .Anyone with a Scan gauge or anything that scans can see the changes.
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01gpgt01
New member
QUOTE taken from Mass flow sensor - Wikipedia, the free encyclopedia and another referance http://www.wellsve.com/sft503/Counterpoint3_2.pdf
"If air density increases due to pressure increase or temperature drop, but the air volume remains constant, the denser air will remove more heat from the wire indicating a higher mass airflow. Unlike the vane meter's paddle sensing element, the hot wire responds directly to air density. "
So what have we learned here? Maff responds to density with HZ values. Meaning more denser air more HZ and more fueling. Less dense less fueling. Imagine that lol.
Like I said your Old monte may respond to it. But every single GP ive messed with doesnt. Infact canned tunes, and dyno tunes you will typically come across dont mess with VE tables either. Guess we are all wrong but your right lol :th_eyesrolling: Anyways im done debating. Lets see what the OP's results are if they choose to do a VE tune.......
And to the OP sorry to have taken your post out of context.
"If air density increases due to pressure increase or temperature drop, but the air volume remains constant, the denser air will remove more heat from the wire indicating a higher mass airflow. Unlike the vane meter's paddle sensing element, the hot wire responds directly to air density. "
So what have we learned here? Maff responds to density with HZ values. Meaning more denser air more HZ and more fueling. Less dense less fueling. Imagine that lol.
Like I said your Old monte may respond to it. But every single GP ive messed with doesnt. Infact canned tunes, and dyno tunes you will typically come across dont mess with VE tables either. Guess we are all wrong but your right lol :th_eyesrolling: Anyways im done debating. Lets see what the OP's results are if they choose to do a VE tune.......
And to the OP sorry to have taken your post out of context.
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gtpsleeper
New member
Nick my question has been answered and I have moved on if you wanna lock this....just saying...
Z34Phoenix
Florida Tuner
Wiki. Lol
FoSHO99
youtu.be/xhrBDcQq2DM
Point is, if you really want a VE tune, go ahead and knock yourself out. But for beginners most of the time all it does is confuse them and seem like a really big waste of time after you do it. I've seen multiple local cars that run low 12's that have never VE tuned and still drive well daily. I know experienced tuners for these cars that never do VE tunes. It may help on other applications but here it doesn't do ****.
gtpsleeper
New member
I just wanted a decent one in case my maf ****s out on me for some reason.... rather be safe than sorry... i understand it doesnt do anything while the maf is functioning....