LTRIM adjust for new Procharger setup
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On The Tree
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From: Stalking the streets of Maryland
LTRIM adjust for new Procharger setup Quick overview:
2000 Firehawk M6
ATI D1-SC Procharger (8# tuner kit)
Walbro GSS340 Intank pump
Billet fuel rails and new -6AN braided fuel line
Aeromotive Boost referenced FPR
FLP LT headers w/ off-road pipes
42# SVO injecters
Current IFR is set to flat 5.51 across the board.
After doing some logging on ATAP I'm finding that at Idle my Ltrms are at about (-5.5) - (-12.7) but tend to hover around (-11.7). In doing partial throttle runs I tried to keep my TPS as close to 18% as possible. My ltrms tend to be in the 0.8 - 4.7 but tend to hover around 2.3.
So what do I need to do to correct these ltrms?
Thanks guys,
BH
2000 Firehawk M6
ATI D1-SC Procharger (8# tuner kit)
Walbro GSS340 Intank pump
Billet fuel rails and new -6AN braided fuel line
Aeromotive Boost referenced FPR
FLP LT headers w/ off-road pipes
42# SVO injecters
Current IFR is set to flat 5.51 across the board.
After doing some logging on ATAP I'm finding that at Idle my Ltrms are at about (-5.5) - (-12.7) but tend to hover around (-11.7). In doing partial throttle runs I tried to keep my TPS as close to 18% as possible. My ltrms tend to be in the 0.8 - 4.7 but tend to hover around 2.3.
So what do I need to do to correct these ltrms?
Thanks guys,
BH
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From: Richmond, VA Where fast cars, well......are hard to come by.
Re: LTRIM adjust for new Procharger setup If it correlates exactly with maf freq, then you can adjust the maf table accordingly. If it follows the map then you can adjust the ifr table. The ifr table is vacuum referened though, so for the 25-30kpa at idle you'll change the 75-70 cells in edit.
Dd you have your ltrims set before putting it on? I noticed a 10% increase in ltrims at part throttle, due to the pcv setup.
Dd you have your ltrims set before putting it on? I noticed a 10% increase in ltrims at part throttle, due to the pcv setup.
Thread Starter
On The Tree
Joined: Dec 2002
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From: Stalking the streets of Maryland
Re: LTRIM adjust for new Procharger setup No my ltrms were not perfect before the swap. I was running slightly positive. It didn't seem to be as drastic a change between idle and partial throttle though as I'm seeing now. How do I view individual cells? I've heard people refer to cell numbers but am not sure how to view them.
BH
BH
Thread Starter
On The Tree
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From: Stalking the streets of Maryland
Re: LTRIM adjust for new Procharger setup Casey,
Someone mentioned that I shouldn't mess with the MAF table if I have a stock MAF. I ditched the GMAF, and descreened my stocker and am using that with the new Prochrager setup.
I would think descreening the stock MAF wouldn't throw it too far out of whack. Or is it something else all together? Let me know what you think.
BH
Someone mentioned that I shouldn't mess with the MAF table if I have a stock MAF. I ditched the GMAF, and descreened my stocker and am using that with the new Prochrager setup.
I would think descreening the stock MAF wouldn't throw it too far out of whack. Or is it something else all together? Let me know what you think.
BH
Moderator
Joined: Nov 2001
Posts: 3,048
Likes: 12
From: Raleigh, NC
Re: LTRIM adjust for new Procharger setup Go to http://www.BlackLs1TA.com
Click on the "Tech" Section.
I have written it up at link item:
"9. My Approach to Fuel Tuning with LS1-Edit"
I just had to type something similar out one too many times.
Differing views are welcome.
Click on the "Tech" Section.
I have written it up at link item:
"9. My Approach to Fuel Tuning with LS1-Edit"
I just had to type something similar out one too many times.
Differing views are welcome.
Thread Starter
On The Tree
Joined: Dec 2002
Posts: 189
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From: Stalking the streets of Maryland
Re: LTRIM adjust for new Procharger setup Great write up man. I was actually listening to what you were saying about the 18% TPS when I started ATAPing my car. But how do I get my idle LTRMs closer to my partial throttle LTRMs? Or when you are talking LTRMs do you suggest I just average out all my LTRMs and go off of that value?
BH
BH
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Joined: Nov 2001
Posts: 3,048
Likes: 12
From: Raleigh, NC
Re: LTRIM adjust for new Procharger setup This is what Al Hanna on the LS1-Edit Email List says he does.
I average LTFT's for each fuel trim cell. Given that level of detail, you
have to decide which fuel trim cell to base your change on (each has a
different purpose and is selected by rpm & load). Since, as you point out,
the fuel trim cells that invoke PE (3, 7, 11, 12, 13, 14, 15, & 22), will go
to zero if LTFT's are negative, using average values in those cells would
misrepresent the LTFT prior to PE mode.
Since we are after high load performance, I based my tuning on using the
highest load non-PE cell (cell 10), so I knew the averages would be solid.
Follow-up measurements and dyno have satisfied me that the approach was
sound.
On the few cars I've measured, I've seen no / low load cells (0, 1, 2, 3, 4)that are overly rich after that change, and in my case, I felt some mild
surging while transitioning to these cells...
I average LTFT's for each fuel trim cell. Given that level of detail, you
have to decide which fuel trim cell to base your change on (each has a
different purpose and is selected by rpm & load). Since, as you point out,
the fuel trim cells that invoke PE (3, 7, 11, 12, 13, 14, 15, & 22), will go
to zero if LTFT's are negative, using average values in those cells would
misrepresent the LTFT prior to PE mode.
Since we are after high load performance, I based my tuning on using the
highest load non-PE cell (cell 10), so I knew the averages would be solid.
Follow-up measurements and dyno have satisfied me that the approach was
sound.
On the few cars I've measured, I've seen no / low load cells (0, 1, 2, 3, 4)that are overly rich after that change, and in my case, I felt some mild
surging while transitioning to these cells...
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Re: LTRIM adjust for new Procharger setup If I were you I wouldn't even bother changing it. As long as you are negative, there is no effect on WOT, and you are well within the parameters of the PCM maximum adjust of -25. If it aint's broke, don't fix it!
-Geoff
-Geoff
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Joined: Nov 2001
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From: South Jersey
Re: LTRIM adjust for new Procharger setup Mike,
Thanks for the good info. I was going to send my PCM out for supercharger tuning, but after looking at your web page I feel more confident to try it myself
Den
Thanks for the good info. I was going to send my PCM out for supercharger tuning, but after looking at your web page I feel more confident to try it myself
Den
