For Level 3 and Log analysis only
Recording log data
A log file shows how the engine actually behaves while driving. Here is how to record one – step by step.
01
What is a log file?
While you drive, the ECU constantly measures and calculates values: engine speed, boost pressure, ignition timing, lambda, temperatures and much more. A logger records these values several times per second – like a tachograph for the engine. The result is a table: one column per value, one row per point in time.
Why this helps
The read-out shows what is in the software. The log file shows how much of it actually reaches the engine in operation – for example whether the boost pressure reaches its target, whether the ignition timing is pulled back because of knock, or how hot things get.
02
What you need
A device that can record the ECU’s measured values. Some Bluetooth adapters with a matching phone app can already do this – but not every one supplies the necessary values fast enough. It works reliably with a diagnostic tool or data logger of the kind workshops and tuners use. We tell you in advance whether your device is sufficient.
Which values?
We tell you which values we need for your ECU – as a list, and for some loggers also as a ready-made profile. Just ask in your enquiry.
03
How to record
- Warm up the engineOil and coolant at normal operating temperature – the oil at least about 80 °C.
- Start the loggerWith the values from our list and at the fastest rate the logger can manage.
- One pull at full loadIn 3rd or 4th gear (automatic: shift manually), full throttle from about 2,000 rpm to just before the rev limiter.
- RepeatTwo or three times, letting the engine cool down briefly in between.
- Save and uploadSave the recording as a file, for example as CSV, and upload it in the enquiry form. If your device shows the ECU’s software number, please add it. Want to look at it yourself first? On View log file, the graphs appear in your browser, without uploading.
Only where it is allowed
Full-throttle runs should only be done where they are allowed and put no one at risk – for example on a closed track. Making the recording is your responsibility or that of your workshop.
04
What we read from it
- Boost pressure: target and actual
- Ignition and knock control, per cylinder
- Lambda: target and actual
- Temperatures: intake air, and exhaust gas as calculated by the ECU
- Torque according to the ECU
Two things the report states plainly
Values from log data are values calculated by the ECU, not a measurement on a dyno. And we cannot vouch for where a recording you send us comes from – the findings apply to exactly this file.
05
Log analysis only
You have a log file but no read-out? Then we analyse the recording on its own. This is a separate service, not a level – with a report and report number, verifiable online like any other report.
You find out how the engine behaves in this recording: whether the boost pressure reaches its target, whether the ignition timing is pulled back because of knock, and how lambda and temperatures develop.
Even more informative with the software number. Send us the software number of the engine or gearbox ECU together with the log file – diagnostic tools and many logger apps display it. If we have the original file for this number, we compare the recording with it: then you can see where the engine or gearbox goes beyond the factory limiters in operation.
What it does not show
Log analysis shows how the engine behaves in this recording, not what has been changed in the software. That requires the read-out.
Here too: the values are values calculated by the ECU, not a measurement on a dyno, and we cannot vouch for where the recording comes from.
Enquiry
Upload a log file
Upload the log file together with the read-out in the enquiry form. We tell you in advance what the analysis costs.
or write directly to info@tuningcheck.de