DATALOGGING

How to datalog

When developping a tuning file datalogging is absolutely necessary. It is even more important than doing dyno runs.

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

The channels to log are:

  • engine speed – rpm
  • pedal postion
  • engineload
  • trottle body postion
  • intake manifold pressure
  • boost pressure request
  • boost pressure actual
  • wastegate dutcycle
  • lambda request
  • lambda actual
  • injection in milligrams
  • injector pulsewidth
  • railpressure
  • mass air flow
  • intake air temperature
  • oil temperare
  • 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 excesheet

See example below

 

Engine LoadEngine LoadEngine LoadBoost PressureEngine SpeedEngine LoadBoost PressureBoost PressureEngine SpeedCoolantIntake AirIgnition
CZAS(specified)(spec. corrected)(actual Value)Control (N75)CZAS(G28)(specified)(actual)CZAS(G28)Temperature (G62)Temperature (G42)Timing Angle
%%%%/min%mbarmbar/min*C*C*PGMP
0,0394,792,529,395,70,06108036,1119099001080934827
0,129792,545,196,10,15112048,110809900,09108093485,3
0,2196,295,552,695,30,25108053,4116010000,181080934913,5
0,3197,79454,91000,34112058,614209900,281120934912,8
0,499,29764,71000,43116065,4144010000,37116093496,8
0,5102,398,566,91000,53120066,9147010100,46116093497,5
0,59102,310067,71000,62124068,4149010100,56120093496
0,68104,5101,568,41000,71128069,2152010200,65124093494,5
0,7810610369,21000,81132069,9153010400,75128093485,3
0,87109104,569,91000,9132069,9153010500,84132093485,3
0,96110,5107,570,71001140071,4157010600,93136093485,3
1,06112,8110,471,41001,09140071,4159010701,03140093485,3
1,15115110,472,21001,18144072,2160010801,12140093486,8
1,25116,5113,472,91001,28148072,9163010901,211440934815,8
1,34117,3113,472,91001,37148072,9165011001,311480944815
1,43119,5114,974,41001,46152074,4168011101,41520944815
1,53121,1117,975,21001,56156075,2170011201,51520934715
1,62123,3119,475,21001,65156075,9172011301,591560934712
1,71124,8120,975,91001,75160076,7173011401,681560934715
1,81126,3122,476,71001,84160076,7175011401,781600944612
1,9127,8123,977,41001,93164077,4176011501,871600944612
2129,3125,477,41002,03164078,2177011601,961640934612,8
2,09130,1125,478,21002,12164078,2178011702,061640944612,8
2,18131,6126,978,91002,21168078,9180011802,151680944612,8
2,28133,8128,478,91002,31168079,7182011802,251680934612,8
2,37135,3129,978,91002,4172078,9183011902,341680944512,8
2,46136,8132,879,71002,5172079,7184012002,431720944512
2,56138,3132,880,51002,59176080,5185012002,531720944512
2,65139,8134,380,51002,68176080,5186012102,621760944512
2,75141,4135,881,21002,78180081,2188012102,711760944512
2,84141,4137,3821002,87180082189012202,811800944512
2,93143,6138,882,71002,96184082,7192012302,91840944511,3
3,03145,1140,383,51003,06184083,51930124031840944511,3
3,12146,6141,884,21003,15188085194012503,091880944511,3
3,21148,1143,3851003,25192085,7195012603,181880944511,3
3,31150,4144,886,51003,34192086,5197012703,281920944512
3,4151,1146,386,51003,43196087,2199012803,371920944511,3
3,5151,9147,887,21003,53200088200012903,461960944510,5
3,59152,6147,888,71003,62200088,7200013003,562000944512
3,68153,4149,389,51003,71204090,2200013203,652000944511,3
3,78154,1149,3911003,81204091200013303,752040944511,3
3,87154,9150,7911003,9208091,7199013403,842080954512
3,96156,4150,791,71004212091,7200013503,932080954512
4,06157,1152,292,51004,09216092,5198013704,032120944512,8
4,15157,9153,793,21004,18216093,2197013804,122160954512,8
4,25158,6153,794,71004,28220094,7197014004,212160944510,5
4,34159,4155,295,51004,37224096,2195014104,31220094459,8
4,43160,2155,296,21004,46224096,2194014304,42240944511,3
4,53160,2156,7971004,56228097193014404,5228094458,3
4,62160,9156,7971004,65232097,7194014604,59228094449,8
4,71160,9156,798,51004,75236098,5192014804,682320944410,5
4,81161,7156,71001004,842400100189015104,78236094448,3
4,9161,7158,2101,51004,932400101,5189015204,87240095449,8
5162,4158,21031005,032440103187015404,96244094449
5,09162,4158,2104,51005,122480105,3187015605,06248095448,3
5,18163,2158,21061005,212520106,8&a

 

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

Depending on the project a different of driving is needed during the logging.

In case of tuning the OEM ecu and OEM engine a WOT (Wide Open Trottle) run in 3rd gear give good information for making a proper tuning.

On dyno: make sure 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 we have to take this into account when analizing the data.

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

Beneath we will give a list of channels which are minimally necessary

always rpm

always pedal position or engineload to see what the driver requests of the engine

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

For turbo diesel engines we need to see at least njection in milligrams or even better injector pulsewidth.

For all petrol engines we need to see actual lambda. If no obd data available an external lambda sensor in exhaust is last resort. In case of older cars the external widebandlambda sensor is even better since old cars many times have the narrowband lambda sensors installed on the car which are not accurate on a WOT run. Ofcourse 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 logged 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.