Teach me something about datalogs

[Bluemustang]

I want to understand some of the parameters in my datalog. How can I tell if one tune produces more power than another? Perhaps it's not that simple.

But what I can tell by looking at parameters like spark advance, MAF lb/min, knock sensor, etc.

What sort of things should I look for? I have a Lund tune and have them checking it for me, but if I want to just understand a little bit more about it.

If anyone out there can provide some helpful tips that would be welcomed and appreciated.

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[Jay-rod427]

For the most part it's data overload. Lund nGuage is not particularly easy to read. Just look at the basics. Spark, rpm, maf. And yes the knock retard to make sure it's not pinging.

 

[kluke15]

sub'd

 

[markmurfie]

This is a list of parameters that I find in my ngauge logs. They are at the top to the Excel file it creates. I usually freeze the top row so that it makes it easier to see what numbers im looking at later down the file.

TIME- time reference on log
RPM- Eninge RPM
ect- Engine coolant temp
act- air charge temp
IAT2- secondary intake air temp, usually on FI cars to get a more acurate reading aftr an intercooler
saftot- Spark advanced final total
FF[ALKY_PCT] - Flex fuel alcohol %
afr_matured - This is a 1 or 0 for setting the lambda AFR once the ECU determines alcohol % reaches its settling point
ETC_ACT- electronic throttle actual position, tells you the actual angle of the butterfly from fully closed.
MAF_in_lbm_per_min- This is the amount of air in lbs passing through the intake. more air is better, but there's inherent error that shows up in the fuel trims
LOAD_as_a_fraction- This is the load the engine has on it. you can think of load as the power efficiency of the engine, but don't confuse more efficiency with more power.
vs_IN_MPH - how fast your car is going
PPS-APP1 - pedal position signal accelerator pedal position one, tells the ECU how much the gas pedal is being pushed , some input not by the driver
PEDAL - how much the pedal is being pushed in a human understandable format
tq_source_pid - what the ECU is deriving its torque value from, there are a number of different sources
MAF_Hz - the MAF sensor value the ECU receives that tells it how much air is going through the intake
AFR1 - air/fuel ratio of bank1
AFR2 - air/fuel ratio of bank2, higher than 1 is lean lower is rich, at WOT its normal to be on the rich side
STFT11 - short term fuel trim bank 1
STFT21 - short term fuel trim bank 2 these are immediately applied fuel corrections from the ECU
LTFT11 - Long term fuel trim bank 1
LTFT21 - Long term fuel trim bank 2 these are learn over trim fuel corrections they are added to the short terms and some times end up canceling each other out.
VCT_EX - vvt position of the exhaust cam shafts
VCT_IN - vvt position of the intake cam shafts
FRP_PSI - fuel rail pressure
Knock - ignition timing retarded by the ECU sensing knock positive values are bad, negative are good, but ideally you want the ECU dialed in so this is as close to 0 as much as possible
imrcm_volts - voltage for the IMRC to tell if they are open or closed
imrc_desired - IMRC desired position this is where the ECU wants the IMRC to be
fpump_dc- fuel pump duty cycle, how hard the fuel pump is working

Not sure if this will help you accomplish your goal of learning to read and understand these log files. I suggest trying to compare some of the before and after revision logs to get a better understanding of what it is your tuner is changing and hopefully you will see why logging and getting the tune revised at least once or twice is a good idea not only for more power on the table but engine safety.

 

[Sasuketr]

I want to understand some of the parameters in my datalog. How can I tell if one tune produces more power than another? Perhaps it's not that simple.

But what I can tell by looking at parameters like spark advance, MAF lb/min, knock sensor, etc.

What sort of things should I look for? I have a Lund tune and have them checking it for me, but if I want to just understand a little bit more about it.

If anyone out there can provide some helpful tips that would be welcomed and appreciated.

Ok i m new to this tuning world too but i think i can help you to understand which tune is making more power.

You need to datalog time,knock sensor, spark timing 1 and 2, vehicle speed

So lets say you loaded the stock tune and see if you are making power over the stock tune with your aftermarket tune!

Pick a safe highway to let it rip (wot) on 3rd gear.
Pick a start and end rpm
Start the datalog with the selected starting rpm ( i choose 1800 rpm)
Wide open throttle pull all the way to your end rpm ( i choose 6500 for stock im)
Do the same with the aftermarket tune

Then go to the log and find your starting time and rpm also highlight knock, spark, and speed!

Subtract the starting time from end time

Calculate average spark timing for the time interval

Calculate positive average knock sensor values for the time interval

Conclusion

If you lets say from 1800 rpm to 6500 had 8.5 seconds with stock tune and only 8.2 seconds with the aftermarket tune and also if the start and end speeds show similar values then thats your first and main clue of making power over stock

Also if average spark timing lets say stock was 22 and tune was 24 thats strike two. Dont forget to subtract the average positive knock value from your average spark value to calculate the real spark average.

The reason i start 1800 rpm or little lower on third gear is to prevent wheel spin with instant torque, so you gradually build power.

You will need and excel sheet to do all this. You can also graph spark vs rpm, time vs rpm and speed vs time for both stock and aftermarket tune.

 

[17GT]

Thank you Mark. Great info.

 

[Sasuketr]

Don't forget that at the end of the day all you are trying to achieve is to lower your time at the finish line! Time is the key here! To prevent human error you can start your log and wot early and end it later but always pick the same start and end values from the log.

 

[Need4Speed15]

The tune that produces a quicker timeslip/mph at the track is making more power!

 

[Sasuketr]

The tune that produces a quicker timeslip/mph at the track is making more power!

No kidding lol. He is trying to figure it out by datalogging. I think reduction in time between specific rpms is the best option in that case!

 

[Bluemustang]

I tired to upload my datalog here but for some reason I can't upload a .csv file.

 

[Sasuketr]

I tired to upload my datalog here but for some reason I can't upload a .csv file.

Just use windows snipping tool to copy it as an image and then you can load it!

 

[Nuked]

http://www.virtualdyno.net/

That's a good tool to use to do A to B comparisons. Choose a flat road, and do a 3rd or 4th gear pull. Main thing to remember is not to get caught up in the peak numbers (just like any dyno) but to compare multiple runs on the same road, same conditions.

 

[Nuked]

http://www.virtualdyno.net/

That's a good tool to use to do A to B comparisons. Choose a flat road, and do a 3rd or 4th gear pull. Main thing to remember is not to get caught up in the peak numbers (just like any dyno) but to compare multiple runs on the same road, same conditions.

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