How To: XTune P1 - Data Logging How To: XTune P2 - Log Review In the previous article I walked you through capturing data via the X-1 GUI 'XTune'. Now that you have that data, you probably want to know what the hell your looking at right? Well that's what I'm going to explain here. The X-1 manages more sensors and data then most will ever need. So I'm going to go over the basic ones that will give you a good idea of the health of your motor and tune, as well as an idea on performance. Start off by opening up XTune, and prep the screen for readability (as noted in the previous How To). Below is a snap shot of the Main1 datachart. IIRC this is from a URD pullied TRD S/C truck. This is a 3rd gear pull, and is very clean and easy to look at, and you can tell quickly that there aren't any major issues. While this chart has almost all the vital information breaking it down could be a bit crazy. Hence the reason for the sub charts (more specific). It is good to go over all the data provided as most of it is critical and there for tuning support. But for beginner's, I'll familiarize you with the more important features. POI - Variable name in XTune Load - Air.Load MAF - Air.Maf TPS - Sensors.Tps Vehicle Speed - Sensor.VSpeed RPMs - Sensors.ESpeed Intake Temp - Sensors.Iat Coolant Temp - Sensors.Ect OEM Spark - Spark.SparkAngleOEM X-1 Spark - Spark.SparkAngle Commanded AFR - Fuel.AfrCmd AFR Bank 1 - Sensors.Wraf1 AFR Bank 2 - Sensors.Wraf2 Fuel Correction Bank 1 - Fuel.acFB1 Fuel Correction Bank 2 - Fuel.acFB2 Duty Cycle Bank 1 - Injectors.InjPortDc1 Duty Cycle Bank 2 - Injectors.InjPortDc2 7th Inj. Duty Cycle - Injectors.InjAuxThrDc Now that you have an idea of what datasets represent what data, lets start examing the data. Air1 You can see where each line is located for the below variables. The charts are plotted almost the same everytime as far as where the graph is located (example: ECT towards the top, IAT towards the bottom, etc). Once you find the graph your looking for click on it to highlight the line and datarow in the spreadsheet below. Inspect the path of the line. Below is a set of guidelines to use as a reference Load - the higher the better MAF - the higher the better IAT - Cooler air is better for performance ECT - Cooler the ECT the more it will help repress any knock RPM - Did you hit redline? Fuel1 Do the same thing with the Fuel1 chart. Click on each line to highlight the data in the spreadsheet that way you can identify the graph. AfrCmd - This is the desired A/F ratio that the motor should be running at. Wraf1 - This is the reported AFR for bank 1, you want this as close to the AfrCmd as possible Wraf2 - This is the reported AFR for bank 2, you want this as close to the AfrCmd as possible acFB1 - Fuel correction factor. You want this value to be as close to 0 as possible (-0.038 = -3.8%). The larger the percent (pos = adding more fuel / neg = removing fuel) means the X-1 is having to compensate for bad data (MAF). acFB2 - Generally speaking 5-7% +/- is acceptable. If you start seeing the adaptives in the 15%, 30% region, then you might want to do some investigation. Fuel2 You can skip past the Fuel2 for now, we'll come back to that in a more advanced follow up. Injector1 You can see in this particular pull, the injectors were at 95% out through 4th gear (see arrows), and peaks right at the top of 3rd. Use DC along with AFR to see that you are getting enough fuel. InjPortDc1 - Duty cycle for the primary injectors is relative. Between 70-90% is acceptable. Higher or lower doesn't mean there is a problem, but if the AFR starts leaning out then larger injectors or upgraded fuel pump would be suggested. InjPortDc2 - see above InjAuxThrDc - for the TRD boosted trucks running the 7th, the DC is generally in the 30-50% range. Spark1 You can use this spark graph to identify engine knock. When knock is detected the ECU will pull timing to protect the motor. In most cases it will slowly re-add the timing. A 1º retard every once in a while is nothing to panic about. If you see a consistent 1º being pulled then you may want to alter your spark table to avoid this. If you see 2-3º of timing being pulled, then you should address why (too much timing, too high ECT, IAT too hot, etc), and correct the issue. In the first image, you'll see the spark table slowly retard timing, that is fine. There are no issues there. In the 2nd image you will see how the timing was pulled at once, then slowly ramped back in. That is a clear sign of engine knock. I have also seen it where, the ECU will do the reverse, and add 2-3º of timing that results in an audible knock. I'm still researching this issue, and can't explain it at this time. AFR1 This chart is redundant. Contains the information you'd find in Fuel1 and Hego1 Hego1 Reports the values from the HEGO sensors (heated exhaust gas oxygen). We'll dive into this in the Advanced write up.