Procedure for WOT tuning...How?
10-30-2003, 08:41 PM
#1
Staging Lane
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Procedure for WOT tuning...How? The procedure to tune for part throttle is straightforward and I've now got my LTFT's averaging -1 to -2. Often pegged at zero.
How do I tune WOT? What do I measure, what do I compare it against to determine if I need to up/down my PE vs RPM table?
Looked it up in http://ls1edit.slowcar.net but the info there is too vague...
How do I tune WOT? What do I measure, what do I compare it against to determine if I need to up/down my PE vs RPM table?
Looked it up in http://ls1edit.slowcar.net but the info there is too vague...
10-31-2003, 08:28 AM
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I wouldn't set the a/f to the same across the board - you will want to be richer at your peak torque, and then lean out gradually.
WOT is much easier to get nailed than part throttle (once your part throttle tuning is done). What tools do you have available (dyno, wideband, etc?)
What I normally do is put the car on the dyno and make sure the initial a/f ratio looks reasonable (as long as it's under 12.9:1 or so everywhere and no anomolies (COT, etc.). Don't worry about the shape to much yet. As long as you aren't getting any KR go ahead and start adding timing while noticing the HP differences. As you add timing you will pick up hp (hopefully) - eventually you will get to a point where that next degree of timing only gives ~ 1-2 additional hp, or the hp stays the same. Once you pass that point you will probably get pre-ignition/detonation. So go ahead and set the timing to the point right before you basically flatlines (0-2 additional hp, etc.)
Now start playing with the a/f curve - normally I just look at peak torque and peak hp - adjust those each run the same way you did spark, while just doing a linear interpolation between the two values. I wouldn't tune for any leaner than 12.8-12.9:1 on a dynojet (depending on how heave the drums are). Figure the inertial mass is about equivalent to a 2800lb car, so you will put a larger load on the motor than the dyno drums.
When done I would back the timing down another degree or two and add a couple of percent to the PE table to ensure things are good on the street/track.
The next step is to go to the track and vary the timing/fuel in the same manner (though you should be *very* close now, so small changes) until you get the best ET's.
WOT is much easier to get nailed than part throttle (once your part throttle tuning is done). What tools do you have available (dyno, wideband, etc?)
What I normally do is put the car on the dyno and make sure the initial a/f ratio looks reasonable (as long as it's under 12.9:1 or so everywhere and no anomolies (COT, etc.). Don't worry about the shape to much yet. As long as you aren't getting any KR go ahead and start adding timing while noticing the HP differences. As you add timing you will pick up hp (hopefully) - eventually you will get to a point where that next degree of timing only gives ~ 1-2 additional hp, or the hp stays the same. Once you pass that point you will probably get pre-ignition/detonation. So go ahead and set the timing to the point right before you basically flatlines (0-2 additional hp, etc.)
Now start playing with the a/f curve - normally I just look at peak torque and peak hp - adjust those each run the same way you did spark, while just doing a linear interpolation between the two values. I wouldn't tune for any leaner than 12.8-12.9:1 on a dynojet (depending on how heave the drums are). Figure the inertial mass is about equivalent to a 2800lb car, so you will put a larger load on the motor than the dyno drums.
When done I would back the timing down another degree or two and add a couple of percent to the PE table to ensure things are good on the street/track.
The next step is to go to the track and vary the timing/fuel in the same manner (though you should be *very* close now, so small changes) until you get the best ET's.
10-31-2003, 10:01 AM
#4
Staging Lane
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No wideband. Just Ls1Edit and EFILive V5.
At first, my LTFT's were averaging +20 ~ +25. I scaled up the MAF table (across the board) by 15% and that brought the LTFT's to -2 ~ -1 which is where that are now.
I have also bumped up by 5% the Base Spark table at drive and park. Ran the car and got 3 KR events that were so tiny (0.28 ~ 0.75 range) and in different RPM ranges, that I think they may not be "real" KR at all (prolly just FLP LT's banging on something due to vibration).
I noticed that sometimes in WOT (not always), the AFR numbers logged by EFILive went from 14.6 to like 11.2 or so. What I am is stumped on how to do the WOT tuning without a wideband for feedback? What do I look at?
At first, my LTFT's were averaging +20 ~ +25. I scaled up the MAF table (across the board) by 15% and that brought the LTFT's to -2 ~ -1 which is where that are now.
I have also bumped up by 5% the Base Spark table at drive and park. Ran the car and got 3 KR events that were so tiny (0.28 ~ 0.75 range) and in different RPM ranges, that I think they may not be "real" KR at all (prolly just FLP LT's banging on something due to vibration).
I noticed that sometimes in WOT (not always), the AFR numbers logged by EFILive went from 14.6 to like 11.2 or so. What I am is stumped on how to do the WOT tuning without a wideband for feedback? What do I look at?
10-31-2003, 11:24 AM
#5
Originally Posted by newbie_tace02
No wideband. Just Ls1Edit and EFILive V5.
At first, my LTFT's were averaging +20 ~ +25. I scaled up the MAF table (across the board) by 15% and that brought the LTFT's to -2 ~ -1 which is where that are now.
At first, my LTFT's were averaging +20 ~ +25. I scaled up the MAF table (across the board) by 15% and that brought the LTFT's to -2 ~ -1 which is where that are now.
10-31-2003, 11:40 AM
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It depends on what is causing the l-trim issue on how you "fix" it. If the maf is ported than I would most certainly scale the table, and even pulling out the screen, or heck, putting on a lid changes the calibration of the maf.
I disagree with the notion that you shouldn't touch the maf scaling table - if anything you know your injector values *more* accurately. But it's just a matter of what is causing the deviation - after all, if everything was working correctly you wouldn't have to change anything.
I disagree with the notion that you shouldn't touch the maf scaling table - if anything you know your injector values *more* accurately. But it's just a matter of what is causing the deviation - after all, if everything was working correctly you wouldn't have to change anything.
10-31-2003, 12:04 PM
#7
I've done testing on a stock car with and without the screen, about 100 miles or so between my testing.
I logged both times with AutoTap, and removing the screen, DOES NOT affect your Ltrims on a stock car.
Most of the time, your Ltrims are out of whack if you do a head and/or cam swap.
If you have a cam with more lift and duration than a stock cam, then the computer has no choice but to "add" fuel at part throttle, hence +ltrims like 10% or more. Scaling the injectors adds the needed fuel for part throttle.
Scaling the MAF does work, but it's not the proper way to do it....
I logged both times with AutoTap, and removing the screen, DOES NOT affect your Ltrims on a stock car.
Most of the time, your Ltrims are out of whack if you do a head and/or cam swap.
If you have a cam with more lift and duration than a stock cam, then the computer has no choice but to "add" fuel at part throttle, hence +ltrims like 10% or more. Scaling the injectors adds the needed fuel for part throttle.
Scaling the MAF does work, but it's not the proper way to do it....
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10-31-2003, 02:38 PM
#8
Staging Lane
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Happens the car is a 2002 LS1 M6 with:
1) Lid + K&N
2) Granatelli MAF & Smooth bellows
3) 160* thermo
4) FLP Longtubes + rear O2 simms
5) SLP Loudmouth
After putting in the FLP's and LM, the car's exhaust smelled like a leaking gas can. Now, since the above indicated part throttle tuning, it doesn't.
How would you go about scaling back the injectors?
Still doesn't help me with my WOT tuning concern.
1) Lid + K&N
2) Granatelli MAF & Smooth bellows
3) 160* thermo
4) FLP Longtubes + rear O2 simms
5) SLP Loudmouth
After putting in the FLP's and LM, the car's exhaust smelled like a leaking gas can. Now, since the above indicated part throttle tuning, it doesn't.
How would you go about scaling back the injectors?
Still doesn't help me with my WOT tuning concern.
Last edited by newbie_tace02; 10-31-2003 at 02:45 PM.
10-31-2003, 03:39 PM
#9
You will need LS1 Edit to scale your injectors.
scale the whole IFR table by what amount you need to get your Ltrims in line.
For example, if you Ltrims are +12-15, then scale your IFR table by 88-90%, this will trick the computer into thinking it has smaller injectors, kinda works backwards...
Do the change, upload it, and drive your car for 10-20 minutes while logging, you'll see a change in your Ltrims.
being slightly negative is a good thing. The stock SS that I did my testing on, had -5 to -10 Ltrims when cruising!!! Zero ltrims is perfect, the computer isn't adding or subtracting fuel....
scale the whole IFR table by what amount you need to get your Ltrims in line.
For example, if you Ltrims are +12-15, then scale your IFR table by 88-90%, this will trick the computer into thinking it has smaller injectors, kinda works backwards...
Do the change, upload it, and drive your car for 10-20 minutes while logging, you'll see a change in your Ltrims.
being slightly negative is a good thing. The stock SS that I did my testing on, had -5 to -10 Ltrims when cruising!!! Zero ltrims is perfect, the computer isn't adding or subtracting fuel....
