Timing Calculator

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Timing Calculator Powered By Docstoc
					Only manipulate the yellow boxes. Mechanical advance represents WOT conditions (no vacuum/100kPa MAP) minus initial adv
Vacuum advance represents additional timing at idle/part throttle/decel conditions.
The table generated is total advance (initial + mechanical + vacuum advance) vs RPM vs Map
Total advance should not exceed 34-36 degrees on most engines at WOT only. Usually need less.
Maximum total advance should be in the 40-50 degrees range on most engines.
Feel free to edit and distribute this as you wish.
Red94Chev

                                                 Map (kPa)
                     20     25      30     35       40      45     50     55           60     65     70
          6000       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          5600       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          5200       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          4800       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          4400       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          4000       38     40      41     42       42      42     42     42          41.5   40.5   38.5
      RPM 3600       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          3200       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          2800       38     40      41     42       42      42     42     42          41.5   40.5   38.5
          2400      36.5   38.5    39.5   40.5     40.5    40.5   40.5   40.5          40     39     37
          2000      33.5   35.5    36.5   37.5     37.5    37.5   37.5   37.5          37     36     34
          1600       30     32      33     34       34      34     34     34          33.5   32.5   30.5
          1200       26     28      29     30       30      30     30     30          29.5   28.5   26.5
          1000       23     25      26     27       27      27     27     27          26.5   25.5   23.5
           800      21.5   23.5    24.5   25.5     25.5    25.5   25.5   25.5          25     24     22
           600      20.5   22.5    23.5   24.5     24.5    24.5   24.5   24.5          24     23     21
           400       20     22      23     24       24      24     24     24          23.5   22.5   20.5


           "Vacuum" Advance (degrees) per MAP value
                  20     25     30     35    40     45             50       55         60     65    70
                   8     10     11     12    12     12             12       12        11.5   10.5   8.5

            "Mechanical" Advance (degrees)                       Computer-controlled
                  6000           18                          Initial Advance (in degrees)
                  5600           18                                        12
                  5200           18
                  4800           18                      Rule of thumb:
                  4400           18                      Cam Duration < 210 @ 0.050 = 10 degrees initial advance
                  4000           18                      Cam Duration 210-220 @ 0.050 = 10-12 degrees initial advance
             RPM 3600            18                      Cam Duration 220-240 @ 0.050 = 14-16 degrees initial advance
                  3200           18                      Cam Duration 240-260 @ 0.050 = 18-20 degrees initial advance
                  2800           18
                  2400          16.5                     MAP values (kPa)            Engine vacuum (inHg)
                  2000          13.5                             100             =            0.0
                  1600           10                               90             =            3.2
                  1200            6                               80             =            6.2
                  1000            3                               70             =            9.1
                   800           1.5                              60             =           12.1
                   600           0.5                              50             =           15.0
                   400            0                               40             =           17.9
30   =   20.9
20   =   23.8
 m/100kPa MAP) minus initial advance

                                                                       40-45
                                                                       35-40
                                                                       30-35
                                                                       25-30
                                                                       20-25
                                                      WOT
               75      80         85     90     95    100              15-20
              36.5    34.5       32.5    31    30.3    30              10-15
              36.5    34.5       32.5    31    30.3    30
                                                                       5-10
              36.5    34.5       32.5    31    30.3    30
              36.5    34.5       32.5    31    30.3    30
              36.5    34.5       32.5    31    30.3    30
              36.5    34.5       32.5    31    30.3    30                Timing
              36.5    34.5       32.5    31    30.3    30
              36.5    34.5       32.5    31    30.3    30
              36.5    34.5       32.5    31    30.3    30
               35      33         31    29.5   28.8   28.5
               32      30         28    26.5   25.8   25.5
              28.5    26.5       24.5    23    22.3    22
              24.5    22.5       20.5    19    18.3    18
              21.5    19.5       17.5    16    15.3    15
               20      18         16    14.5   13.8   13.5                           20
               19      17         15    13.5   12.8   12.5                                  35
              18.5    16.5       14.5    13    12.3    12                                          50
                                                                                                           65
                                                                                            MAP (kPa)             80
                                                                                                                         95
                75        80     85      90      95     100
                6.5      4.5     2.5      1      0.3     0
             Set "main spark bias" constant to 0
             Set "coolant spark bias" constant to 9.84 and redo the "Coolant Compensation Spark vs Vac" table to desired spark + 9.84.
             Set "initial spark advance" constant to 0 as per factory 0* distribitor setting. should match (e.g. 4 degrees)
             If desired, may set distributor with some advance (e.g. 4 degrees). "Initial spark advance" value in .bin should match (e.g. 4 deg
             At low MAP values, a slight decrease in timing can be used to slow down the vehicle better

0 degrees initial advance
 10-12 degrees initial advance
 14-16 degrees initial advance
 18-20 degrees initial advance

                     Other thoughts to keep in mind:
                     GM HEI mechanical advance is limited to 20 degrees
                     Tradionally, using weaker springs or heavier weights in mechanical advance serves to
                     get this component of timing in sooner (@ lower RPM). Old school hot rodders aim for timing "all in"
                     by 2800-3000 RPM
                     Aluminum heads can generally withstand more timing than iron heads.
                     http://www.chevyhiperformance.com/howto/97438/index.html
Total SA = main spark (- main spark bias) + coolant spark (- coolant spark bias) + EGR spark correction - EGR s
Some .xdf files, such as the 0D_v1_02.xdf, DO NOT incorporate bias constants into the tables.
Press F10 while in TunerproRT to view the "item comments" if you are unsure.
For a tutorial on ECM/PCM timing logics:     http://www.thirdgen.org/techboard/diy-prom/207418-spark-correction-lv8-
                                             http://www.thirdgen.org/techboard/diy-prom/317768-timing-logics-anyone
                                                             Timing Curve


                                                                            45

                                                                            40

                                                                            35

                                                                            30

                                                                            25

                                                                            20

                                                                            15

                                                                            10

                                                                            5
                                                                     6000
                                                                    5200
                                                             4400
                                                      3600
                                               2800
                                        2000
                                 1200




                                                               RPM
                           800
                     400




                95



 table to desired spark + 9.84.

ue in .bin should match (e.g. 4 degrees)




r timing "all in"
+ EGR spark correction - EGR spark bias


rom/207418-spark-correction-lv8-vs.html
rom/317768-timing-logics-anyone.html
Total Spark Advance
                                                          Map (kPa)
                             20   25      30        35       40         45
                      6000
                      5600
                      5200
                      4800
                      4400
                      4000
     RPM              3600
                      3200
                      2800
                      2400
                      2000
                      1600
                      1200
                      1000
                       800
                       600
                       400

Main Spark Table
                                                          Map (kPa)
                             20   25      30        35       40         45
                      6000
                      5600
                      5200
                      4800
                      4400
                      4000
     RPM              3600
                      3200
                      2800
                      2400
                      2000
                      1600
                      1200
                      1000
                       800
                       600
                       400

Coolant Spark Table
                                       Map (kPa) "converted from VAC in kPa"
                             20   30      40        50         60        70
                      128
                      116
                      104
                       92
                       80
                       68
Temp (oC)              56
                       44
                       32
                       20
                        8
                       -4
                      -16
                      -28

EGR Spark table
                                                                              Map (kPa)
                                  100         97           95          92        90            87
                     4000          0           0            0           0         0             0
      RPM            3200          0           0            0           0         0             0
                     2400          0           0            0           0         0             0
                     1600          0           0            0           0         0             0
                      800          0           0            0           0         0             0

Biases
Main Spark                                Distributor advance
Initial Spark                                              0
Coolant Spark                             **Note: not calculated in Max Spark calculation
EGR Spark

Please note that Main spark table, EGR table, and Coolant table DO NOT incorporate the spark biases.
Check your .xdf file to see if these tables DO or DO NOT automatically subtract the spark bias values.
You will need to add the appropriate spark biases to all relevant tables for this calculator to be accurate if your biase
50   55    60     65   70   75   80   85   90




50   55    60     65   70   75   80   85   90




80   90   100.0
                  85          82          80          70           60   50   40
                   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


              Max Spark advance
                           42



e the spark biases.
park bias values.
 tor to be accurate if your biases are automatically subtracted.
     WOT
95   100




     WOT
95   100
       Inj PW (msec)      TBI      MPFI
RPM                    Inj DC%   Inj DC%
6000       6.35          127%      64%
5900       6.35          125%      62%     TBI    IDC (%) = [4 * IPW (ms) * RPM]/1200
5800       6.35          123%      61%     MPFI   IDC (%) = [2 * IPW (ms) * RPM]/1200
5700       6.35          121%      60%
5600       6.35          119%      59%
5500       6.35          116%      58%
5400       6.35          114%      57%
5300       6.35          112%      56%
5200       6.35          110%      55%
5100       6.35          108%      54%
5000       6.35          106%      53%
4900       6.35          104%      52%
4800       6.35          102%      51%
4700       6.35           99%      50%
4600       6.35           97%      49%
4500       6.35           95%      48%
4400       6.35           93%      47%
4300       6.35           91%      46%
4200       6.35           89%      44%
4100       6.35           87%      43%
4000       6.35           85%      42%
3900       6.35           83%      41%
3800       6.35           80%      40%
3700       6.35           78%      39%
3600       6.35           76%      38%
3500       6.35           74%      37%
3400       6.35           72%      36%
3300       6.35           70%      35%
3200       6.35           68%      34%
3100       6.35           66%      33%
3000       6.35           64%      32%
2900       6.35           61%      31%
2800       6.35           59%      30%
2700       6.35           57%      29%
2600       6.35           55%      28%
2500       6.35           53%      26%
2400       6.35           51%      25%
2300       6.35           49%      24%
2200       6.35           47%      23%
2100       6.35           44%      22%
2000       6.35           42%      21%
1900       6.35           40%      20%
1800       6.35           38%      19%
1700       6.35           36%      18%
1600       6.35           34%      17%
1500       6.35           32%      16%
1400       6.35           30%      15%
1300       6.35           28%      14%
1200       6.35           25%      13%
1100       6.35           23%      12%
1000       6.35           21%      11%
 900       6.35           19%      10%
 800       6.35           17%       8%
700   6.35   15%   7%
600   6.35   13%   6%
500   6.35   11%   5%
PW (ms) * RPM]/1200
PW (ms) * RPM]/1200