Easiest A/F adjust w/edit
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Launching!
Joined: May 2002
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From: Evans GA
Easiest A/F adjust w/edit I have atap and edit now, so what would be the easiest way to determine and set the right A/F ratio with edit. I dont have cats so i am probably going to turn the COT off too. What would be a dangerous timing adjustment too?
Re: Easiest A/F adjust w/edit Assuming you are NA.
The easiest way to determine your WOT a/f ratio is to check your front O2's at WOT. They should level off around .9, but anything between .85 and .95 is fine. To get a better reading of your a/f ratio you will have to go to a wideband dyno.
The best way to set the a/f ratio at WOT is using the PE (power enrichment tables). Don't go too nutz. Small changes in the table make big changes to the a/f ratio.
If your running NA without NOS, there really isn't a dangerous timing adjustment for you. If your car see's Knock up top, it will just pull the timing itself. The object is not to have any KR though.
Most cars can take 29 to 30 deg of advance at WOT. Some cars, like mine, suck and can't.
Your a/f ratio at part-throttle conditions will automatically be controlled by the LTerm adjustments. Being you have the CATs pulled, and will be turning off the COT protection, ensure that your LTerms at part-throttle are around -2 at all times. This will make your WOT tuning much more consistant.
To adjust Lterms, adjustments can be made to the MAF transfer function table (HZ to g/sec) or the Injector Deliver Tables.
Good Luck
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The easiest way to determine your WOT a/f ratio is to check your front O2's at WOT. They should level off around .9, but anything between .85 and .95 is fine. To get a better reading of your a/f ratio you will have to go to a wideband dyno.
The best way to set the a/f ratio at WOT is using the PE (power enrichment tables). Don't go too nutz. Small changes in the table make big changes to the a/f ratio.
If your running NA without NOS, there really isn't a dangerous timing adjustment for you. If your car see's Knock up top, it will just pull the timing itself. The object is not to have any KR though.
Most cars can take 29 to 30 deg of advance at WOT. Some cars, like mine, suck and can't.
Your a/f ratio at part-throttle conditions will automatically be controlled by the LTerm adjustments. Being you have the CATs pulled, and will be turning off the COT protection, ensure that your LTerms at part-throttle are around -2 at all times. This will make your WOT tuning much more consistant.
To adjust Lterms, adjustments can be made to the MAF transfer function table (HZ to g/sec) or the Injector Deliver Tables.
Good Luck
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Thread Starter
Launching!
Joined: May 2002
Posts: 287
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From: Evans GA
Re: Easiest A/F adjust w/edit Here are some Atap generalizations from a recent log:
these are WOT readings
O2s hung around .880 to .900
Fuel trim cell: saw alot of 15, 21, 22
Mass air freq: max was around 8800
LTRMs were anywhere from 12-18
for normal driving the I saw the LTRMs as anywhere from 5 to 15.
Any advice for editing?
these are WOT readings
O2s hung around .880 to .900
Fuel trim cell: saw alot of 15, 21, 22
Mass air freq: max was around 8800
LTRMs were anywhere from 12-18
for normal driving the I saw the LTRMs as anywhere from 5 to 15.
Any advice for editing?
Re: Easiest A/F adjust w/edit Given your LTerms, it looks as though you are running slightly lean.
Multiply your entire MAF transfer function table by 107%. This should drop your LTerms to hang around 0 a little more.
Your WOT O2's look like they are within the acceptable range .85 to .95.
What was your WOT timing. Was there any Knock Retard. These are things that you will want to watch as well. KR at WOT can sometimes indicate an excessivly lean condition.
Multiply your entire MAF transfer function table by 107%. This should drop your LTerms to hang around 0 a little more.
Your WOT O2's look like they are within the acceptable range .85 to .95.
What was your WOT timing. Was there any Knock Retard. These are things that you will want to watch as well. KR at WOT can sometimes indicate an excessivly lean condition.
TECH Regular
Joined: Apr 2002
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From: LS1.chat
Re: Easiest A/F adjust w/edit </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>
Multiply your entire MAF transfer function table by 107%. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
NO!
<strong>
Multiply your entire MAF transfer function table by 107%. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
NO!
Re: Easiest A/F adjust w/edit </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by JAS:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>
Multiply your entire MAF transfer function table by 107%. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
NO!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>
Multiply your entire MAF transfer function table by 107%. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
NO!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
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Thread Starter
Launching!
Joined: May 2002
Posts: 287
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From: Evans GA
Re: Easiest A/F adjust w/edit The wot timing was around 32 i think and there was knock retard of about 3 degrees on some runs but not very consistant (ie value would only occupy one excell cell per wot run and wouldnt occur every run) plus my y pipe plays the jamacain steel drums on the floor board, so i am not worried too much about kr at this time, as i should have the y pipe stablized in the near future.
What to the strms do and would they hold any authority for tuning?
<small>[ September 23, 2002, 02:46 PM: Message edited by: Zshark ]</small>
What to the strms do and would they hold any authority for tuning?
<small>[ September 23, 2002, 02:46 PM: Message edited by: Zshark ]</small>
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Verdad Gallardo Re: Easiest A/F adjust w/edit Sterms are the short term adjustment calculation that the computer makes to determine how it is going to correct your a/f ratio
Lterms are the long term adjustment calculations that the computer makes, in accordance with the Sterm calculation, to determine how it is going to correct the a/f ratio
For example:
STerms: The PCM calculates your relative a/f ratio every cycle (I am guessing once every ~250 millisec). The results are stored in the PCM active memory (the stuff that goes away every time your car is turned off).
LTerms: The PCM, using a compilation of the STerm data, calculates LTerms (ie addition / subtraction of fuel) for specific points of engine Rpm and Load. The LTerm results go through some magical calculation and are stored in the PCM passive memory (stuff that stays after you turn off the ignition) so as to slowly dial in the proper a/f ratio of your car over time.
In regards to tuning, STerms are of relatively little importance unless your car cannot work its way down to near zero LTerms on its own. Then you have to see what the deal is with your STerms and why they are providing funky values for you LTerms.
LTerms are the result of Sterms, and really do the majority of dictating how fuel is going to be adjusted. Soooo, we all look at Lterms, and ignore Sterms.
Good Luck
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
Lterms are the long term adjustment calculations that the computer makes, in accordance with the Sterm calculation, to determine how it is going to correct the a/f ratio
For example:
STerms: The PCM calculates your relative a/f ratio every cycle (I am guessing once every ~250 millisec). The results are stored in the PCM active memory (the stuff that goes away every time your car is turned off).
LTerms: The PCM, using a compilation of the STerm data, calculates LTerms (ie addition / subtraction of fuel) for specific points of engine Rpm and Load. The LTerm results go through some magical calculation and are stored in the PCM passive memory (stuff that stays after you turn off the ignition) so as to slowly dial in the proper a/f ratio of your car over time.
In regards to tuning, STerms are of relatively little importance unless your car cannot work its way down to near zero LTerms on its own. Then you have to see what the deal is with your STerms and why they are providing funky values for you LTerms.
LTerms are the result of Sterms, and really do the majority of dictating how fuel is going to be adjusted. Soooo, we all look at Lterms, and ignore Sterms.
Good Luck
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Teching In
Joined: Apr 2002
Posts: 33
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From: Blue Springs, MO (KC suburb)
Re: Easiest A/F adjust w/edit I would like to know why JAS says NO to multiplying the MAF by 107%
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
<small>[ September 27, 2002, 09:37 AM: Message edited by: Jim Shearer ]</small>
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
<small>[ September 27, 2002, 09:37 AM: Message edited by: Jim Shearer ]</small>
Re: Easiest A/F adjust w/edit I think what JAS is getting at, is that we are basically fooking with the MAF transfer function. The MAF's from the factory are callibrated, and very accurate, our "adjustments" are basically putting them out of whack.
Most cars if you leave them alone will work their way down to around 0 LTerms. Mine will do it, but it takes around 2000 miles to get it done.
I don't have time to wait 2000 miles in between dyno pulls, so I have made adjustmets to my MAF to have the LTerms right around -2 as soon as I put in a new program.
I have also made adjustments to my timing table and PE curves (on the dyno) to compensate for this though.
That, or JAS has no idea what we are talking about and is just a *****.
Most cars if you leave them alone will work their way down to around 0 LTerms. Mine will do it, but it takes around 2000 miles to get it done.
I don't have time to wait 2000 miles in between dyno pulls, so I have made adjustmets to my MAF to have the LTerms right around -2 as soon as I put in a new program.
I have also made adjustments to my timing table and PE curves (on the dyno) to compensate for this though.
That, or JAS has no idea what we are talking about and is just a *****.