Where's the torque?
07-26-2004, 10:21 PM
#1
Where's the torque? Dyno post
Given the above, am I doing something wrong in the tuning which would kill my torque, or is it just the cam?
Since the dyno, I've dropped my LTFT's from an average of -7 to an average of -3. I also leaned out my PE by 103% from 2400-8000, and leaned it out a bit more at (hmm, was it 5600 or 6000, I forget). At any rate, I'm a bit miffed at the loss of torque. What will I gain back by fixing the AFR? I haven't messed with the timing, other than getting rid of knock. Might decreasing timing help the torque?
Given the above, am I doing something wrong in the tuning which would kill my torque, or is it just the cam?
Since the dyno, I've dropped my LTFT's from an average of -7 to an average of -3. I also leaned out my PE by 103% from 2400-8000, and leaned it out a bit more at (hmm, was it 5600 or 6000, I forget). At any rate, I'm a bit miffed at the loss of torque. What will I gain back by fixing the AFR? I haven't messed with the timing, other than getting rid of knock. Might decreasing timing help the torque?
07-27-2004, 08:33 AM
#2
You typically want the A/F a little fat at max torque and leaning out as you move to max hp. Did you have to pull timing down low? I would have suggested adding timing. If you are losing a lot of timing to KR, maybe TR6 plugs might help since you have a 11.2 CR.
07-27-2004, 09:10 PM
#5
1) Multiplied entire IFR by 102%
2) Multiplied PE 2400-5200 by 98%
3) Multiplied PE 6000-7200 by 98%
4) Looks like I fubar'ed the PE 5600 entry. Looks like in my attempt to fix that dip to 11.2:1 between 5800-5900, I multiplied by 98%, but then multiplied by 104% instead of another 96%. Not even sure if that's the correct fix here, correct RPM(s) to modify and/or maybe it's COT kicking in.
5) Timing was completely stock on the dyno.
6) After dyno I added 2* 3200-4400 x 0.4-0.48gms/cyl, 2400-2800 x .52-.72gms/cyl, and 3200-8000 x 0.52-1.0gms/cyl, then pulled timing as needed to remove KR in the specific cells.
7) After modifying the IFR & PE, the car is bucking more in a wide RPM range at cruise. Before it was very smooth with the modified VE table.
Does raising the IFR 2% and reducing PE by 2% effectively lean out the car 4%, or should I lean it out more?
2) Multiplied PE 2400-5200 by 98%
3) Multiplied PE 6000-7200 by 98%
4) Looks like I fubar'ed the PE 5600 entry. Looks like in my attempt to fix that dip to 11.2:1 between 5800-5900, I multiplied by 98%, but then multiplied by 104% instead of another 96%. Not even sure if that's the correct fix here, correct RPM(s) to modify and/or maybe it's COT kicking in.
5) Timing was completely stock on the dyno.
6) After dyno I added 2* 3200-4400 x 0.4-0.48gms/cyl, 2400-2800 x .52-.72gms/cyl, and 3200-8000 x 0.52-1.0gms/cyl, then pulled timing as needed to remove KR in the specific cells.
7) After modifying the IFR & PE, the car is bucking more in a wide RPM range at cruise. Before it was very smooth with the modified VE table.
Does raising the IFR 2% and reducing PE by 2% effectively lean out the car 4%, or should I lean it out more?
Code:
PE PE RPM Dyno Post-dyno 0000 1.1676 1.1676 0400 1.1560 1.1560 0800 1.1676 1.1676 1200 1.1667 1.1667 1600 1.2074 1.2074 2000 1.2258 1.2258 2400 1.2016 1.1773 2800 1.2132 1.1890 3200 1.2190 1.1948 3600 1.2016 1.1773 4000 1.1783 1.1550 4400 1.1841 1.1609 4800 1.2016 1.1773 5200 1.2074 1.1831 5600 1.1676 1.1860 6000 1.2132 1.1890 6400 1.1676 1.1444 6800 1.1793 1.1560 7200 1.1793 1.1560
07-27-2004, 10:00 PM
#6
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1.IFR*1.02 will lean out the mixture.
2. The pe values are moving in the lean direction.
4. your 5600 entry is actually 2% richer. Turn off you COT it will only make things harder to tune when it kicks in. The afr you are trying to acheive will have it kicking in all the time.
Raising the IFR by 2% leans it out all the way acroos the board and then reducing the PE by 2% will lean you even more and that is probably why you picked up some kr
A more effective trackable method woud be to fool around with the ve table instead of the IFR table. You scaling the IFR table applies blanket fueling even where you dont want it. Specifcally at WOT
2. The pe values are moving in the lean direction.
4. your 5600 entry is actually 2% richer. Turn off you COT it will only make things harder to tune when it kicks in. The afr you are trying to acheive will have it kicking in all the time.
Raising the IFR by 2% leans it out all the way acroos the board and then reducing the PE by 2% will lean you even more and that is probably why you picked up some kr
A more effective trackable method woud be to fool around with the ve table instead of the IFR table. You scaling the IFR table applies blanket fueling even where you dont want it. Specifcally at WOT
07-27-2004, 10:07 PM
#7
But I have cat's and I have no intention on removing them. Can I desensitize the COT table, or somehow not totally delete the COT but reduce it's influence on WOT?
I logged 18000 samples to create a custom VE table, and it seemed to drive great until I tweaked the PE & IFR. Should I revert IFR to stock (I have stock injectors) and merely use the VE? Can you give me the specific steps to using the VE table instead of the IFR?
I logged 18000 samples to create a custom VE table, and it seemed to drive great until I tweaked the PE & IFR. Should I revert IFR to stock (I have stock injectors) and merely use the VE? Can you give me the specific steps to using the VE table instead of the IFR?
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07-27-2004, 10:23 PM
#8
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I have cats also and have been runnong with COT off for a while now and so far i have had no problems. I dont know about de-sensitizing them because i just turned them off. Take the IFR table back to stock and log to see what rpm ranges your LTrims are positive. Do you trims lock to 0 when you go to WOT with the stock IFR. To help get them in line just multiply the ve table by the percentage your ltrims are positve only at those ranges.
Do you have a AFR plot from the dyno?
Do you have a AFR plot from the dyno?
07-27-2004, 10:34 PM
#9
I've got an AFR plot on paper, but no scanner...nor did I ask for the data printout. I don't think I'd have a problem getting the raw dynojet files if I asked.
I doubt my stock IFR table will lock my LTFT's to zero at WOT. My dyno IFR table is ~13% lower than stock.
This part is unclear to me. How do I translate LTFT value's in specific cells into these VE ranges?
I doubt my stock IFR table will lock my LTFT's to zero at WOT. My dyno IFR table is ~13% lower than stock.
To help get them in line just multiply the ve table by the percentage your ltrims are positve only at those ranges.
07-27-2004, 10:43 PM
#10
Maybe if I'd read slower it'll help 
OK: Revert IFR to stock, continue from modified VE table, log LTFT & RPM, then reduce the matching RPM range in the VE table by a percentage to get the LTFT's barely negative to lock at zero in WOT. Right?
OK: Revert IFR to stock, continue from modified VE table, log LTFT & RPM, then reduce the matching RPM range in the VE table by a percentage to get the LTFT's barely negative to lock at zero in WOT. Right?
07-28-2004, 07:33 AM
#11
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Originally Posted by JimMueller
I've got an AFR plot on paper, but no scanner...nor did I ask for the data printout. I don't think I'd have a problem getting the raw dynojet files if I asked.
I doubt my stock IFR table will lock my LTFT's to zero at WOT. My dyno IFR table is ~13% lower than stock.
This part is unclear to me. How do I translate LTFT value's in specific cells into these VE ranges?
OK: Revert IFR to stock, continue from modified VE table, log LTFT & RPM, then reduce the matching RPM range in the VE table by a percentage to get the LTFT's barely negative to lock at zero in WOT. Right?
I doubt my stock IFR table will lock my LTFT's to zero at WOT. My dyno IFR table is ~13% lower than stock.
This part is unclear to me. How do I translate LTFT value's in specific cells into these VE ranges?
OK: Revert IFR to stock, continue from modified VE table, log LTFT & RPM, then reduce the matching RPM range in the VE table by a percentage to get the LTFT's barely negative to lock at zero in WOT. Right?
Do you have HPtuners? If yes you can use the LTFT histogram to help you with getting them in order. The histogram is referenced by map and rpm
Increase the matchin RPM and Map on the ve table to get it to richen up. Bigger numbers on the ve table = rich, smaller = lean
07-28-2004, 09:57 AM
#12
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Jim-Ditch the COT completely...with headers and the cats further downstream, they'll never get that hot anyway. I've been running with COT off in my car for a year...With it on, the mixtures are too unsteady. Now if you were running the car WOT for miles on end, then they might get a little toasty...
07-28-2004, 12:16 PM
#13
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The only person that burned their cats up that I have read about was doing runs on the slt flats for the nevada state silver classic. That was the one and only time i have seen it happen. I would just get rid of it to save yourself the headache of the computer correction your tuned a/f ratio because it thinks that cats are getting to hot. That is prolly why you are geting so fat around 5600
07-28-2004, 04:31 PM
#14
I have Edit, not HPTuners. I also use the LS1 Tuning Analysis spreadsheet written by NBM_WS6 (I think that was his handle), but I'm not sure it gives the same historgram off the top of my head.
I'll turn off COT, but I'm curious how I can do this VE/LTFT procedure without HPTuners..
I'll turn off COT, but I'm curious how I can do this VE/LTFT procedure without HPTuners..
07-28-2004, 04:57 PM
#15
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Excel or access but its a lot of work.
Basically you have to import the csv file into either program and run averages where your LTFT's are postive then take that back to the ve table and modify the culprit cells.
Basically you have to import the csv file into either program and run averages where your LTFT's are postive then take that back to the ve table and modify the culprit cells.
07-28-2004, 08:09 PM
#16
I might have a local contact who has HPTuners for a '98. Perhaps I can get his assistance. So for the positive LTFT's, I'll need to increase the appropriate VE ranges and vice versa. Is it a straight percentage? If the LTFT's are +6% in a range, do I increase those VE cells ~7-8% to get my LTFT's slightly negative?
07-29-2004, 08:37 PM
#18
If your LTFT's are a few points too negative, does it really matter in the broader scope of things? Mine averaged -7 in the summer because they were set during the winter months to ~-3. Short of the AFR being too rich, the car behaved very well on the street.
What will that minor adjustment in the LTFT's gain me? For now I reverted to the tune I had on the dyno, turned off COT, kept the new timing table, and leaned out PE by 4%. Doing it the VE way just seems like more of a headache than I'm willing to try at the moment.
What will that minor adjustment in the LTFT's gain me? For now I reverted to the tune I had on the dyno, turned off COT, kept the new timing table, and leaned out PE by 4%. Doing it the VE way just seems like more of a headache than I'm willing to try at the moment.