DATALOGGING

HOW TO DATALOG

When developing a tuning file, datalogging is of utter importance. It is even more important than doing dyno runs. Testing on a dyno and on the road should meet certain conditions. The main limitation of data logging is lack of available channels. However, although there are many preferable channels to log, a few are absolutely necessary.

Always start with a baseline of the complete original car. This is needed to see how the car responds in the normal, OEM condition. If there is a problem within the OEM condition, stop the project and solve the issue before going further.

The channels to log are:

  • engine speed – rpm
  • pedal position
  • engine load
  • throttle body position
  • intake manifold pressure
  • boost pressure request
  • boost pressure actual
  • wastegate duty cycle
  • lambda request
  • lambda actual
  • injection in milligrams
  • injector pulse width
  • rail pressure
  • mass air flow
  • intake air temperature
  • oil temperature
  • water temperature
  • exhaust gas temperature
  • ignition per cylinder
  • ignition adaption (advancement/retarding)
  • knock voltage
  • cam phasing


The best way to show all this data is to store data as excel sheet. See an example below:

 

Engine Load Engine Load Engine Load Boost Pressure Engine Speed Engine Load Boost Pressure Boost Pressure Engine Speed Coolant Intake Air Ignition
CZAS (specified) (spec. corrected) (actual Value) Control (N75) CZAS (G28) (specified) (actual) CZAS (G28) Temperature (G62) Temperature (G42) Timing Angle
% % % % /min % mbar mbar /min *C *C *PGMP
0,03 94,7 92,5 29,3 95,7 0,06 1080 36,1 1190 990 0 1080 93 48 27
0,12 97 92,5 45,1 96,1 0,15 1120 48,1 1080 990 0,09 1080 93 48 5,3
0,21 96,2 95,5 52,6 95,3 0,25 1080 53,4 1160 1000 0,18 1080 93 49 13,5
0,31 97,7 94 54,9 100 0,34 1120 58,6 1420 990 0,28 1120 93 49 12,8
0,4 99,2 97 64,7 100 0,43 1160 65,4 1440 1000 0,37 1160 93 49 6,8
0,5 102,3 98,5 66,9 100 0,53 1200 66,9 1470 1010 0,46 1160 93 49 7,5
0,59 102,3 100 67,7 100 0,62 1240 68,4 1490 1010 0,56 1200 93 49 6
0,68 104,5 101,5 68,4 100 0,71 1280 69,2 1520 1020 0,65 1240 93 49 4,5
0,78 106 103 69,2 100 0,81 1320 69,9 1530 1040 0,75 1280 93 48 5,3
0,87 109 104,5 69,9 100 0,9 1320 69,9 1530 1050 0,84 1320 93 48 5,3
0,96 110,5 107,5 70,7 100 1 1400 71,4 1570 1060 0,93 1360 93 48 5,3
1,06 112,8 110,4 71,4 100 1,09 1400 71,4 1590 1070 1,03 1400 93 48 5,3
1,15 115 110,4 72,2 100 1,18 1440 72,2 1600 1080 1,12 1400 93 48 6,8
1,25 116,5 113,4 72,9 100 1,28 1480 72,9 1630 1090 1,21 1440 93 48 15,8
1,34 117,3 113,4 72,9 100 1,37 1480 72,9 1650 1100 1,31 1480 94 48 15
1,43 119,5 114,9 74,4 100 1,46 1520 74,4 1680 1110 1,4 1520 94 48 15
1,53 121,1 117,9 75,2 100 1,56 1560 75,2 1700 1120 1,5 1520 93 47 15
1,62 123,3 119,4 75,2 100 1,65 1560 75,9 1720 1130 1,59 1560 93 47 12
1,71 124,8 120,9 75,9 100 1,75 1600 76,7 1730 1140 1,68 1560 93 47 15
1,81 126,3 122,4 76,7 100 1,84 1600 76,7 1750 1140 1,78 1600 94 46 12
1,9 127,8 123,9 77,4 100 1,93 1640 77,4 1760 1150 1,87 1600 94 46 12
2 129,3 125,4 77,4 100 2,03 1640 78,2 1770 1160 1,96 1640 93 46 12,8
2,09 130,1 125,4 78,2 100 2,12 1640 78,2 1780 1170 2,06 1640 94 46 12,8
2,18 131,6 126,9 78,9 100 2,21 1680 78,9 1800 1180 2,15 1680 94 46 12,8
2,28 133,8 128,4 78,9 100 2,31 1680 79,7 1820 1180 2,25 1680 93 46 12,8
2,37 135,3 129,9 78,9 100 2,4 1720 78,9 1830 1190 2,34 1680 94 45 12,8
2,46 136,8 132,8 79,7 100 2,5 1720 79,7 1840 1200 2,43 1720 94 45 12
2,56 138,3 132,8 80,5 100 2,59 1760 80,5 1850 1200 2,53 1720 94 45 12
2,65 139,8 134,3 80,5 100 2,68 1760 80,5 1860 1210 2,62 1760 94 45 12
2,75 141,4 135,8 81,2 100 2,78 1800 81,2 1880 1210 2,71 1760 94 45 12
2,84 141,4 137,3 82 100 2,87 1800 82 1890 1220 2,81 1800 94 45 12
2,93 143,6 138,8 82,7 100 2,96 1840 82,7 1920 1230 2,9 1840 94 45 11,3
3,03 145,1 140,3 83,5 100 3,06 1840 83,5 1930 1240 3 1840 94 45 11,3
3,12 146,6 141,8 84,2 100 3,15 1880 85 1940 1250 3,09 1880 94 45 11,3
3,21 148,1 143,3 85 100 3,25 1920 85,7 1950 1260 3,18 1880 94 45 11,3
3,31 150,4 144,8 86,5 100 3,34 1920 86,5 1970 1270 3,28 1920 94 45 12
3,4 151,1 146,3 86,5 100 3,43 1960 87,2 1990 1280 3,37 1920 94 45 11,3
3,5 151,9 147,8 87,2 100 3,53 2000 88 2000 1290 3,46 1960 94 45 10,5
3,59 152,6 147,8 88,7 100 3,62 2000 88,7 2000 1300 3,56 2000 94 45 12
3,68 153,4 149,3 89,5 100 3,71 2040 90,2 2000 1320 3,65 2000 94 45 11,3
3,78 154,1 149,3 91 100 3,81 2040 91 2000 1330 3,75 2040 94 45 11,3
3,87 154,9 150,7 91 100 3,9 2080 91,7 1990 1340 3,84 2080 95 45 12
3,96 156,4 150,7 91,7 100 4 2120 91,7 2000 1350 3,93 2080 95 45 12
4,06 157,1 152,2 92,5 100 4,09 2160 92,5 1980 1370 4,03 2120 94 45 12,8
4,15 157,9 153,7 93,2 100 4,18 2160 93,2 1970 1380 4,12 2160 95 45 12,8
4,25 158,6 153,7 94,7 100 4,28 2200 94,7 1970 1400 4,21 2160 94 45 10,5
4,34 159,4 155,2 95,5 100 4,37 2240 96,2 1950 1410 4,31 2200 94 45 9,8
4,43 160,2 155,2 96,2 100 4,46 2240 96,2 1940 1430 4,4 2240 94 45 11,3
4,53 160,2 156,7 97 100 4,56 2280 97 1930 1440 4,5 2280 94 45 8,3
4,62 160,9 156,7 97 100 4,65 2320 97,7 1940 1460 4,59 2280 94 44 9,8
4,71 160,9 156,7 98,5 100 4,75 2360 98,5 1920 1480 4,68 2320 94 44 10,5
4,81 161,7 156,7 100 100 4,84 2400 100 1890 1510 4,78 2360 94 44 8,3
4,9 161,7 158,2 101,5 100 4,93 2400 101,5 1890 1520 4,87 2400 95 44 9,8
5 162,4 158,2 103 100 5,03 2440 103 1870 1540 4,96 2440 94 44 9
5,09 162,4 158,2 104,5 100 5,12 2480 105,3 1870 1560 5,06 2480 95 44 8,3
5,18 163,2 158,2 106 100 5,21 2520 106,8&a

 

As you can see, this way it is very easy to see how the engine performs at a specific rpm and pedal position.

Depending on the project several different driving conditions are needed during the logging.

In case of tuning an OEM ECU and OEM engine, a WOT (Wide Open Throttle) run in 3rd gear gives good information for making a proper tuning.

On dyno:

make sure the engine is working on normal operating temperature. Set correct load value, arrange proper cooling by a fan which simulates real driving wind on the engine, intercooler, but also under the car to cool the exhaust. Set ambient correction to DIN values.

On road:

find a good, safe, quiet piece of road where you can test safely. Note the current ambient pressure, temperature and humidity because we have to take this into account when analyzing the data.

The biggest problem when datalogging many cars is that there are not enough channels available to log.

Beneath we will give a list of channels which are the bare minimum:

It is of utter importance to always log the engine speed i.e. rpm and the pedal position or engine load to see what the driver requests of the engine. Other preferable channels depend on the type of engine, so cast a glance at the general tips below.

For turbo petrol engines we need to see actual boost before and after tuning. If the actual boost is not available, at least measure intake manifold pressure.

For turbo diesel engines we need to see at least injection in milligrams or even better, injector pulse width.

For all petrol engines we need to see actual lambda. If no OBD data is available, an external lambda sensor in exhaust is the last resort.

In case of older cars the external wideband lambda sensor is even better. Namely, old cars often have the narrowband lambda sensors installed when the car is not accurate on the WOT run.

Of course, the ECU knows this and when going WOT, the ECU does not use the lambda sensor to control fuel but instead uses the fuel maps inside the ECU. So when a narrowband sensor is installed and you log this data during WOT, remember not to use this data.

For all petrol engines we need to see ignition or even better, ignition adaption. Ignition adaption allows us to see the ECU correcting ignition according to knock and temperatures.

In short:

  • Datalogging should be inevitable when tuning
  • It should start with the baseline of an original car
  • A list of channels to log and a real-life example are available on this page
  • There are many channels desirable but not all are always available
  • However, there are necessary channels for every type of engine and you can find them in this article

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