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Late model engines overfueling at WOT

https://www.speed-talk.com/forum/viewtopic.php?t=52035

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Re: Late model engines overfueling at WOT

Posted: Thu Jan 18, 2018 8:18 pm
by Ed Wright
MadBill wrote: ↑Sat Jan 13, 2018 1:01 am Back in the day, GM vehicles destined for certain high altitude locations were equipped with specific p.n. leaner carbs.
And, now many engines come with different computer calibrations.

Re: Late model engines overfueling at WOT

Posted: Fri Jan 19, 2018 12:34 am
by FC-Pilot
I know the company I work for seams to have many of its cars sooty after testing on the track, and this is with production powertrain so there is no excuse of it being an early prototype tune.

Paul

Re: Late model engines overfueling at WOT

Posted: Fri Jan 19, 2018 5:25 am
by Belgian1979
Keith Morganstein wrote: ↑Sat Jan 13, 2018 8:36 am My ford mod v8 with OBD1 would push a bit of black smoke when first going to WOT, then clear up. Engine/car was abnormally fast for what it was.
AE would do that if improperly tuned at high loads.

Re: Late model engines overfueling at WOT

Posted: Fri Jan 19, 2018 8:35 am
by Ed Wright
4vpc wrote: ↑Thu Jan 11, 2018 10:40 pm As intake temps rise the ECU richens the mix to stave off det'. Is this news?
Been tuning GM EFI vehicles since 1985, I have never seen a calibration that adds fuel for high Intake Air Temps. They do back up the timing.

WOT Air/Fuel ratios in the high 11-1 range is fairly common for late model, stock GM vehicles.
Lean them enough (and you do nothing to prevent it) they will go into C.O.T. Mode to protect the cats. That lowers EGTs, won't melt the cats, or catch anything on fire. LOL
For carb guys, the previously mentioned AE fuel, is like the accelerator pump squirt from a carb.

Re: Late model engines overfueling at WOT

Posted: Fri Jan 19, 2018 8:16 pm
by Ed Wright
Had a brain fart. Just did a '93 LT1 Corvette chip today, and that one does have an A/F correction for Intake temp. Right now I can't think of another one that does. Sorry.

Re: Late model engines overfueling at WOT

Posted: Fri Jan 19, 2018 8:34 pm
by user-23911
What about coolant temp?


It's far more important if you're either towing or pulling up a long hill.

Re: Late model engines overfueling at WOT

Posted: Sat Jan 20, 2018 9:30 am
by Morgo
Should I add that my Camry was sold new in Germany with free autobahn speeds so there is a possibility that Toyota programmed ECU to survive ten´s to hundered of kilometers of full throttle driving.Don't know;just quessing..

Re: Late model engines overfueling at WOT

Posted: Sat Jan 20, 2018 9:40 am
by Ed Wright
joe 90 wrote: ↑Fri Jan 19, 2018 8:34 pm What about coolant temp?


It's far more important if you're either towing or pulling up a long hill.
They all have fueling corrections for coolant temp. Mostly for Open Loop, and P.E. Mode (wide open throttle)

Re: Late model engines overfueling at WOT

Posted: Sun Jan 21, 2018 12:35 am
by In-Tech
The IAT correction has been available for quite a while, originally just spark but also fueling now. Ed pointed out a 93Lt1 having it, here is a 2011 ZR1 Vette. I have never seen one ADD fuel, as you can see this one takes away fuel with Intake Air Temp as it should be. Just for reference, a multiplier of 1 = no change, anything under 1 is taking fuel away. This(ZR1) table can have a maximum multiplier of 4(FFFFh) and minimum multiplier of 0(0000h).

As to the questions about overfueling at WOT, it doesn't overfuel with the factory cal to most extent. When it goes into cat save mode the AFR's can end up in the 10's, TO SAVE THE CATS.

Anything running at richer than stoich will put soot in the tailpipe on PUMP GAS.

Code: Select all

	Injector Flow Rate Multiplier Vs. IAT
 
  Deg. C    Mult.
    -40    0.9994 
    -30    0.9994 
    -20    0.9994 
    -10    0.9994 
      0    0.9994 
     10    0.9994 
     20    0.9994 
     30    0.9994 
     40    0.9855 
     50    0.9714 
     60    0.9614 
     70    0.9534 
     80    0.9475 
     90    0.9424 
    100    0.9424 
    110    0.9424 
    120    0.9424

The spark correction is like it looks, positive number adds timing, negative number takes timing away.

Code: Select all

	IAT Spark Advance Correction Vs. IAT Vs. Load
 
  gm/cyl.                                                                                                                  Deg. C
             -40    -35    -30    -25    -20    -15    -10    -5      0      5     10     15     20     25     30     35     40     45     50     55     60     65     70     75     80     85     90     95     100    105    110    115    120  
    0.08      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0 
    0.12      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0 
    0.16      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0 
    0.20      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0 
    0.24      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0 
    0.28      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0   -1.5   -2.5   -2.5   -2.5   -2.5   -2.5   -2.5   -2.5   -2.5   -1.5   -1.5   -1.5 
    0.32      0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0   -1.5   -2.5   -3.0   -3.5   -3.5   -3.5   -4.0   -4.5   -5.0   -5.0   -5.0   -5.0 
    0.36      1.0    1.0    1.0    1.0    1.0    1.0    1.0    1.0    1.0    1.0    1.0    1.0    1.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0   -2.0   -3.0   -3.5   -4.0   -4.0   -4.0   -4.5   -5.0   -5.5   -5.5   -6.0   -7.0 
    0.40      2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    1.0    0.0    0.0    0.0    0.0    0.0    0.0    0.0   -2.0   -3.5   -4.0   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0   -6.0   -7.0   -8.0 
    0.44      3.0    3.0    3.0    3.0    3.0    3.0    3.0    3.0    3.0    3.0    3.0    3.0    3.0    2.0    1.0    1.0    1.0    0.5    0.0    0.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.0   -6.5   -6.5   -9.0  -10.0 
    0.48      4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    3.0    2.0    2.0    2.0    1.5    1.0    0.5    0.0   -2.5   -4.0   -5.0   -6.0   -6.0   -6.0   -6.5   -6.5   -7.0   -8.0  -10.0  -11.0 
    0.52      4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    3.0    2.5    2.5    2.5    1.5    1.0    0.5    0.0   -3.0   -4.0   -5.0   -6.0   -6.0   -6.0   -6.5   -6.5   -7.0   -9.0  -11.0  -12.0 
    0.56      4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    3.0    2.5    2.5    2.5    1.5    1.0    0.5    0.0   -3.0   -4.0   -5.0   -6.0   -6.0   -6.0   -6.5   -6.5   -7.0  -10.0  -11.0  -12.0 
    0.60      4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    3.5    3.0    2.5    2.5    1.5    1.0    0.5    0.0   -2.5   -4.0   -5.0   -6.0   -6.0   -6.0   -6.5   -6.5   -7.0  -10.0  -11.0  -12.0 
    0.64      4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    4.0    3.5    3.0    2.5    2.5    1.5    1.0    0.0    0.0   -2.5   -4.0   -5.0   -6.0   -6.0   -6.0   -6.5   -6.5   -7.0  -10.0  -11.0  -12.0 
    0.68      8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    6.0    3.5    2.5    2.0    1.5    1.0    0.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.5   -7.0  -10.0  -11.0  -12.0 
    0.72      8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    8.0    6.0    3.5    2.5    2.5    1.5    1.0    0.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.5   -7.0  -10.0  -12.0  -12.0 
    0.76     10.0   10.0   10.0   10.0   10.0   10.0   10.0   10.0   10.0   10.0   10.0   10.0   10.0    8.0    4.5    3.0    2.5    1.5    1.0    0.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.5   -6.5  -10.0  -12.0  -12.0 
    0.80     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    6.0    3.5    2.5    1.5    1.0    0.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.0   -6.5  -10.0  -12.0  -12.0 
    0.84     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    7.0    4.0    2.5    1.5    1.0    0.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.0   -6.5  -10.0  -12.0  -12.0 
    0.88     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    7.5    6.0    4.0    3.5    2.5    1.0    0.0   -2.5   -4.0   -4.5   -5.5   -5.5   -5.5   -6.0   -6.0   -6.0  -10.0  -12.0  -12.0 
    0.92     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    8.5    6.0    5.0    4.0    2.5    1.5    0.0   -2.5   -4.0   -4.5   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    0.96     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    9.0    6.0    6.0    4.5    3.0    1.5    0.0   -2.5   -4.0   -4.5   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    1.00     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    9.5    5.5    5.5    4.0    2.5    1.5    0.0   -2.5   -4.0   -4.5   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    1.04     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    9.5    5.5    5.5    4.5    3.5    2.0    2.0   -2.5   -4.0   -4.5   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    1.08     11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0   11.0    9.0    5.5    5.5    4.5    3.0    2.0    2.0   -2.5   -3.5   -4.5   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    1.12     10.5   11.0   11.0   10.5   10.5   10.5   10.5   10.5   10.5   10.5   10.5   10.5   10.5   10.5    8.5    6.0    5.5    4.5    3.0    2.0    2.0   -2.5   -3.5   -4.0   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    1.16      7.0    7.0    7.0    7.0    7.0    7.0    7.0    7.0    7.0    7.0    7.0    7.0    9.5   10.0    8.5    7.0    3.0    3.0    3.0    2.0    2.0   -2.0   -3.5   -4.0   -5.0   -5.0   -5.0   -5.5   -5.5   -6.0  -10.0  -12.0  -12.0 
    1.20      2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    9.5   10.0    8.5    7.0    2.0    2.0    2.0    2.0    2.0   -2.0   -3.5   -4.0   -4.5   -4.5   -4.5   -5.0   -5.0   -5.5  -10.0  -12.0  -12.0 
    1.24      2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    9.5   10.0    8.5    7.0    2.0    2.0    2.0    2.0    2.0   -2.0   -3.0   -3.5   -4.5   -4.5   -4.5   -5.0   -5.0   -5.5  -10.0  -12.0  -12.0 
    1.28      2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    9.5   10.0    8.5    7.0    2.0    2.0    2.0    2.0    2.0   -1.5   -3.0   -3.5   -4.0   -4.0   -4.0   -4.5   -5.0   -5.5  -10.0  -12.0  -12.0 
    1.32      2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    9.5   10.0    8.5    7.0    2.0    2.0    2.0    2.0    2.0   -1.5   -2.5   -3.0   -4.0   -4.0   -4.0   -4.5   -4.5   -5.5  -10.0  -12.0  -12.0 
    1.36      2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    2.0    9.5   10.0    8.5    7.0    2.0    2.0    2.0    2.0    2.0   -1.5   -2.5   -3.0   -3.5   -3.5   -3.5   -4.0   -4.5   -5.0  -10.0  -12.0  -12.0
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