As a tuner, one of the most integral parts of what I do is reviewing and interpreting datalogs. One thing that I find sorely lacking in most DIY tuners’ toolboxes are the tools with which to properly view and quantify the data they have collected. Being able to visually see data helps identify problems such as faulty O2s, slipping supercharger belts and proper fueling and spark advance curves.
Let me walk you through a simple example with my personal car – a supercharged 1995 GT running CBAZA strategy U4P0 base calibration. The combo consists of the stock 150,000 mile longblock, Trickflow heads, S-trim at 15psi and a water methanol kit through a 4R70W automatic transmission. This example finds me dialing in the water/methanol kit with both pre and post blower nozzles. Datalogging software and hardware in this example is Clint Garrity’s BinaryEditor through a Moates Quarterhorse chip.
Before we start go ahead and download a few things to follow along… Dyno Chart, Datalog, SCT’s LiveLink. The calibration used in this example is available on request if you drop me an email – wes@tpsperformance.com.
The first thing to do is get LiveLink installed. Even if you do not have any SCT hardware, you can still use LiveLink to visualize and zoom in on your datalogs as long as they are in a standard CSV format with the column headers in the first row. BinaryEditor saves logs in this format “out of the box”. twEECer’s CalCon datalog files can be saved out as CSV and they will be viewable as well.
I will not give you a step by step instruction on using LiveLink – it is quite intuitive (and also useful if you have a SCT handheld to log ODBII data in realtime). Check the help file under “Toolbar Options” for a quick runthrough of the options.
Once you have LiveLink loaded, go to the “File” menu and select “Open”. Locate the datalog file you downloaded. If you datalog a lot of parameters they may not all fit in the list on the left – you can either trim out some of the columns in Excel or right click the listing and change the font size to something smaller to allow additional room.
With the datalog open, I normally first click on “RPM” to give me a feel for where my pull is. You can clearly see the RPM jump up towards the end of the log – this is the pull on the dyno. A nifty trick to zoom in on a particular portion of a log is to RIGHT CLICK AND HOLD on the start of the section of interest and while holding drag to the end of the section of interest. LiveLink will automatically zoom in on this portion for you.
Go ahead and do the right click and drag zoom on the pull on the dyno. You will get a screen similar to this:
Dyno Run
You can check the checkbox next to each parameter you wish to view. A few interesting ones to watch are LOAD, PW1, SPARK, MAFV and ACT.
Running through each of the params mentioned, you see as RPM increases LOAD goes up – this is typical of centrifugal blower cars… the more you spin ‘em the most boost they make. This is verified with the dyno chart. A N/A car will show a LOAD that closely follows the torque curve on the dyno chart as the volumetric efficiency of the vehicle peaks and then decreases. A load in the 180s is roughly correct for the observed boost so that is an excellent indicator this vehicle is calibrated correctly.
PW1 is the pulsewidth of the 60lb injectors – you see that it steadily increases as airflow increases, this is good.
SPARK follows what I am commanding in my calibration, again, this is good.
MAFV shows that I still have some headroom with my peak at about 4.5v on the SCT BA2400 meter.
ACT is an interesting one. Because of my ACT sensor placement, I am not seeing as rapid of a temperature change when the methanol fires (there is very little room for the mixture to evaporate) but you can clearly see that the temperature peaks and then falls. The somewhat erratic AFR (and large difference between AFR on the dyno chart and LAMBSE in the datalog) shows that the meth is indeed spraying and further tuning is needed to dial it in to what I am looking for.
HEGO cycling
If you click the “Fully Expand Chart” button in the toolbar, you can then turn on HEGO1 and HEGO2 – you’ll see that HEGO1 is cycling as we would expect but HEGO2 is dead. On most cars this would be a problem, in this case I have disabled HEGO2 in the calibration to accommodate a wideband O2 sensor in its spot.
In a nutshell, that is it. Visualizing data is a very important part of what I do as a tuner. By incorporating it into your tuning regimen I have no doubt your tuning and troubleshooting will improve. LiveLink proves to be quite useful in viewing data allowing much quicker access to “pan n’ scan” around than if you were using Excel.