VE tables the best way to tune?
07-11-2004, 09:54 PM
#1
VE tables the best way to tune? hello, i was wondoring what the best way to tune was. my buddy wants to mess with edit but all he's used it the PMS on his and a few other quick stangs running around. they all us percentages so he was wondoring how to take the VE's and turn them into a percentage
also- will i need to drill a hole in the TB with a 224/228 563/571 113 cam inside an M6 car?
also- will i need to drill a hole in the TB with a 224/228 563/571 113 cam inside an M6 car?
07-11-2004, 10:11 PM
#3
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I have been silent about this subject lately, because I have seen some confusing things while I have been tuning my car. I made excellent progress using the VE tables to smooth out my LTFTs after I got my trims negative using the IFR table. I went back to a stock tune (with stock IFR table that made my LTFTs 10-12%positive) and tried tuning the VE table only, and it doesn't seem to want to cooperate. I am still working on it though. I wish I had more insight into what the table actually does...
07-11-2004, 10:25 PM
#4
Originally Posted by Another_User
I wish I had more insight into what the table actually does...
AMEN! something alil more simple to tune ls1's would be GREAT
"more fuel at 2.2k.. less at 2.5...... more at 4k.... more timing thru the entire curve" - that kind of thing
07-11-2004, 10:27 PM
#5
There are some that contridict this but.......
When your car figures out the LTerms there are two things that it has to determine, 1) What a/f it is at, 2) What adjustment needs to be made to bring the a/f back into specs (or STerm as we see them).
This is a tricky calculation because both results are largely influenced off of the same input, the input air flow. At unsteady MAP conditions, the condition that most modified cars run at in the lower RPM, the VE table takes a much larger role in determining what airflow is entering the engine. If the VE table is incorrect, not only will it bring the car off target on the a/f to begin with, but it will also effect what correction the car 'thinks' it has to apply.
If you get too far off with the VE table, closed loop capability of the car breaks down. You'll still have your LTerms reporting, but the car will begin to stumble, being that the actual a/f the car is still not correct even after the supposed 'correction'.
With an accurate VE table, everything falls into place. The LTerms are correct and the supporting corrections to the LTerms (STerms) are correct. You can mark a good VE table by seeing that not only are the LTerm near zero, but more importantly the STerms remain near zero.
Basically, what I am saying is don't use the LTerms to adjust the VE table. Get a wideband, or a good MAF with a calculator. If you do insist on using the stock O2's to determine the VE table, kick the car to open loop, and back-calculate the O2 voltage to the predicted a/f. Once finished with the VE, kick the car back to closed loop and ignore what the LTerms are.
Good Luck
When your car figures out the LTerms there are two things that it has to determine, 1) What a/f it is at, 2) What adjustment needs to be made to bring the a/f back into specs (or STerm as we see them).
This is a tricky calculation because both results are largely influenced off of the same input, the input air flow. At unsteady MAP conditions, the condition that most modified cars run at in the lower RPM, the VE table takes a much larger role in determining what airflow is entering the engine. If the VE table is incorrect, not only will it bring the car off target on the a/f to begin with, but it will also effect what correction the car 'thinks' it has to apply.
If you get too far off with the VE table, closed loop capability of the car breaks down. You'll still have your LTerms reporting, but the car will begin to stumble, being that the actual a/f the car is still not correct even after the supposed 'correction'.
With an accurate VE table, everything falls into place. The LTerms are correct and the supporting corrections to the LTerms (STerms) are correct. You can mark a good VE table by seeing that not only are the LTerm near zero, but more importantly the STerms remain near zero.
Basically, what I am saying is don't use the LTerms to adjust the VE table. Get a wideband, or a good MAF with a calculator. If you do insist on using the stock O2's to determine the VE table, kick the car to open loop, and back-calculate the O2 voltage to the predicted a/f. Once finished with the VE, kick the car back to closed loop and ignore what the LTerms are.
Good Luck
07-12-2004, 04:17 PM
#6
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Originally Posted by NoGo
There are some that contridict this but.......
When your car figures out the LTerms there are two things that it has to determine, 1) What a/f it is at, 2) What adjustment needs to be made to bring the a/f back into specs (or STerm as we see them).
This is a tricky calculation because both results are largely influenced off of the same input, the input air flow. At unsteady MAP conditions, the condition that most modified cars run at in the lower RPM, the VE table takes a much larger role in determining what airflow is entering the engine. If the VE table is incorrect, not only will it bring the car off target on the a/f to begin with, but it will also effect what correction the car 'thinks' it has to apply.
If you get too far off with the VE table, closed loop capability of the car breaks down. You'll still have your LTerms reporting, but the car will begin to stumble, being that the actual a/f the car is still not correct even after the supposed 'correction'.
With an accurate VE table, everything falls into place. The LTerms are correct and the supporting corrections to the LTerms (STerms) are correct. You can mark a good VE table by seeing that not only are the LTerm near zero, but more importantly the STerms remain near zero.
Basically, what I am saying is don't use the LTerms to adjust the VE table. Get a wideband, or a good MAF with a calculator. If you do insist on using the stock O2's to determine the VE table, kick the car to open loop, and back-calculate the O2 voltage to the predicted a/f. Once finished with the VE, kick the car back to closed loop and ignore what the LTerms are.
Good Luck
When your car figures out the LTerms there are two things that it has to determine, 1) What a/f it is at, 2) What adjustment needs to be made to bring the a/f back into specs (or STerm as we see them).
This is a tricky calculation because both results are largely influenced off of the same input, the input air flow. At unsteady MAP conditions, the condition that most modified cars run at in the lower RPM, the VE table takes a much larger role in determining what airflow is entering the engine. If the VE table is incorrect, not only will it bring the car off target on the a/f to begin with, but it will also effect what correction the car 'thinks' it has to apply.
If you get too far off with the VE table, closed loop capability of the car breaks down. You'll still have your LTerms reporting, but the car will begin to stumble, being that the actual a/f the car is still not correct even after the supposed 'correction'.
With an accurate VE table, everything falls into place. The LTerms are correct and the supporting corrections to the LTerms (STerms) are correct. You can mark a good VE table by seeing that not only are the LTerm near zero, but more importantly the STerms remain near zero.
Basically, what I am saying is don't use the LTerms to adjust the VE table. Get a wideband, or a good MAF with a calculator. If you do insist on using the stock O2's to determine the VE table, kick the car to open loop, and back-calculate the O2 voltage to the predicted a/f. Once finished with the VE, kick the car back to closed loop and ignore what the LTerms are.
Good Luck
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07-12-2004, 06:49 PM
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Originally Posted by HumpinSS
Another_user do you have an AIM account or msn
Yep...I got one now. MSN
Last edited by Another_User; 07-12-2004 at 07:07 PM.
07-12-2004, 07:59 PM
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Originally Posted by HumpinSS
07-13-2004, 08:18 AM
#12
The VE table is the right place to tune if you've modded the engine in such a way that you've altered it's volumetric efficiency. Cam, exhaust, intake manifold are the common ones in this area. These affect cylinder filling and charge dilution, which in turn affect the chemical reaction (burn) and resulting discharge (HC, O2).
The IFR table is the right place to tune if you've changed injectors, or changed delivery pressure. It's a convenient and mostly effective place to tune for VE changes, but not the right place. Joe Overton argued this one here a while back, do a search for the info that resulted.
The MAF table is the right place to tune if you've changed the MAF sensor.
The IFR table is the right place to tune if you've changed injectors, or changed delivery pressure. It's a convenient and mostly effective place to tune for VE changes, but not the right place. Joe Overton argued this one here a while back, do a search for the info that resulted.
The MAF table is the right place to tune if you've changed the MAF sensor.
07-14-2004, 09:05 AM
#15
As long as you're still running 58psi fuel pressure at the rail, you've made no change to fuel delivery...it's all about the VE table.
I'll admit I used my IFR table to make one global adjustment in the fuel delivery, which I will back out later. I had +5 to +10% LTFTs everywhere when the engine initially went in. Rather than jack the entire VE table at the time, I bumped the IFR table to move things close to zero. When I started getting LTFTs straddling zero...some negative, some positive, I hit the VE table and started recurving.
My plans for this Winter are to aggregate all the EFILive data I've captured and mathematically derive an accurate VE table.
I'll admit I used my IFR table to make one global adjustment in the fuel delivery, which I will back out later. I had +5 to +10% LTFTs everywhere when the engine initially went in. Rather than jack the entire VE table at the time, I bumped the IFR table to move things close to zero. When I started getting LTFTs straddling zero...some negative, some positive, I hit the VE table and started recurving.
My plans for this Winter are to aggregate all the EFILive data I've captured and mathematically derive an accurate VE table.
07-14-2004, 04:08 PM
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Originally Posted by crainholio
As long as you're still running 58psi fuel pressure at the rail, you've made no change to fuel delivery...it's all about the VE table.
I'll admit I used my IFR table to make one global adjustment in the fuel delivery, which I will back out later. I had +5 to +10% LTFTs everywhere when the engine initially went in. Rather than jack the entire VE table at the time, I bumped the IFR table to move things close to zero. When I started getting LTFTs straddling zero...some negative, some positive, I hit the VE table and started recurving.
My plans for this Winter are to aggregate all the EFILive data I've captured and mathematically derive an accurate VE table.
I'll admit I used my IFR table to make one global adjustment in the fuel delivery, which I will back out later. I had +5 to +10% LTFTs everywhere when the engine initially went in. Rather than jack the entire VE table at the time, I bumped the IFR table to move things close to zero. When I started getting LTFTs straddling zero...some negative, some positive, I hit the VE table and started recurving.
My plans for this Winter are to aggregate all the EFILive data I've captured and mathematically derive an accurate VE table.
07-14-2004, 05:16 PM
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Originally Posted by HumpinSS
Anoter_User check this thread out http://www.hptuners.com/forum/YaBB.p...00;start=20#20
:in best Cartman voice: GM.......I hate you guys.
07-14-2004, 05:19 PM
#19
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because the whole PCM is driven by map,rpm and g/cyl
. Well after fooling around withe secondary ve table the trims are finally starting to move after a week or so of fooling around with it
. Well after fooling around withe secondary ve table the trims are finally starting to move after a week or so of fooling around with it
07-14-2004, 06:40 PM
#20
"It makes absolutely NO sense why changing you VE would change where you are in the spark tables, other than if your fueling is more or less accurate you would be running better or worse and pulling less vacuum seen by your MAP sensor."
You've answered it yourself
. VE is a grams/cyl table- with MAP and RPM axes. So if you change g/cyl for a particular cell you are changing the referenced Timing. Timing tables have axes of g/cyl and RPM.
You've answered it yourself
. VE is a grams/cyl table- with MAP and RPM axes. So if you change g/cyl for a particular cell you are changing the referenced Timing. Timing tables have axes of g/cyl and RPM.