Importance of Data Logging for Tuning

Every good tuner will know the importance of data logging, yet not all of them will do their best to base their tuning projects on thorough data logs. It is possible to tune a car without data logging, that is true, but that would be like saying it is possible to translate a paper to a language you don’t know very well. It can be done up to a point, but it is going to include a lot of guessing and it is not going to be very good. And as the paper gets more complicated, the importance of knowing the language well increases. In the world of tuning, the ‘more complicated’ comes with higher tuning stages, so for a good stage 3 tuning project, precise data logging becomes paramount.

With this mindset, we have always tried to get data logs for our tuning projects. After a few decades of doing this, we have a remarkable database of tuning files that are based on precise data logs. We also have a lot of experience with fixing ECU files developed by other tuners through proper use of information gathered from data logging.

Moreover, even for the files that we develop from scratch, a good data log is very important. It gives us the information that is necessary in order to develop a tuning file that makes the absolute most of any engine and stock or aftermarket part without ever going past any safety level.

In short, good data logging lets us develop a tuning file that provides the most power without risking anything as it removes any need for (un)educated guessing. That alone should be enough to tell you how important data logging is, but there is more.

This is why we decided to make this blog post. Educating our customers on this matter will make our job a lot easier and also provide our customers with the best service for the car owners who put their trust into their hands.

What Is Data Logging in Tuning

In short, data logging is a way for us to see what the ECU was reading from all the systems throughout a particular RPM range. This progressive nature of a good data log is very important. For example, if you have just the information about your maximum boost, or ignition correction it will be next to useless.

The reason for this is that this kind of information is, of course, important, but it gets its real value in only context. And that context includes other information from the same data log. It will tell us when a certain ignition correction occurred, why it is so and if and how it can be changed to improve performance without questioning safety and reliability.

Data logging is basically a precise set of information given within a specific context that lets a tuner see all the important aspects that are necessary to create an efficient and reliable ECU tune. Such precise information and the context that surrounds it allows good tuners to get really close to the limits of components without ever crossing it, so a good data log is the best way to get the most power in the safest way.

Having in mind all this, it is no wonder data logging is a must for custom projects such as Stage 3 upgrades and race car builds. We also prefer it for any kind of tuning, so, as we have said, the vast majority of our tuning files are based on data logs.

What Makes Data Logging so Important

Data logging provides us with information about the important parameters within an ECU. There are so many aspects of engine operation that are interconnected and that affect all the other aspects. Changing one parameter does not bring one single result, but it also affects a number of other parameters. It can be limited by them, which means the change will not yield the desired result, or it can affect them directly, creating a problem in a different place.

Some of the most important channels to log include the following:

• Engine speed – rpm
• Pedal position
• Engine load (psi)
• Throttle body position
• Vehicle speed
• Intake manifold pressure
• Boost pressure request
• Boost pressure actual
• Wastegate duty cycle
• Lambda request
• Lambda actual
• Injection in milligrams
• Injector pulse width
• Rail pressure
• Mass air flow
• Intake air temperature
• Oil temperature
• Water temperature
• Exhaust gas temperature
• Ignition per cylinder
• Ignition adaption (advancement/retarding)
• Knock voltage
• Cam phasing
• and more…

Just reading the list above should tell you why knowing this information for any given conditions can give the best results for those particular conditions, be they the best performance or the best fuel efficiency, for example.

But it is not just about efficiency. This information lets us prevent or fix any issues that may arise, regardless of if they limit performance or hamper reliability. For example, data logging during a drag run lets us know exactly what was going on at any point during the run which can help us fine tune the software and make the engine the best and safest it can be. Moreover, comparing the actual results from two runs can show you exactly where the differences lie and how you can make your car as fast as possible at any point of the run.

Data logging also lets you track changes in knock, various pressures and temperatures and more, so you can make sure the engine is completely safe at any point.

These few examples should be enough to tell you why data logging is important for pretty much any tune, let alone Stage 3 tuning projects that introduce a lot of custom work and specific hardware changes that can make a huge difference in literally every aspect of engine operation. With a good data log, you can observe all those changes and the differences they make and adjust the tune to the best and safest levels possible.

A Few Examples of Engine Parameters Important for Data Logging

While we have already given the above list which shows some of the most commonly observed values, let us give a closer explanation on a few of them.

Air/Fuel Ratio

It shows the ratio between the amount of air and fuel that is burned inside the cylinders. There is actually a perfect ratio for each kind of fuel, but there are also numerous other variables that may affect the most desired ratio for certain driving conditions. Aside from ensuring the best performance, air/fuel ratio is also very important for keeping the engine temperatures under dangerous levels.

While there are significant differences between different fuel types, air/fuel ratio is important for all of them and detailed information about air and fuel ratio in relation with RPM, throttle position, speed and many other aspects helps us make the best use of the engine potential in a completely safe way.

Fuel Pressure

This is especially important for turbo engines. This pressure needs to follow the intake manifold pressure in order to preserve the desired air to fuel ratio. If this is not the case, the engine will not operate as it is supposed to. Also, irregularities in the fuel pressure can show issues with some hardware parts such as the fuel pump.

Engine Oil Pressure

Engine oil pressure is very important for preventing damage to the engine. If the pressure is too low, the damage is almost inevitable. Now imagine the level of damage on stage 3 upgrades with aftermarket turbos for example, or in racing conditions when engines are put under strain even when things are perfect. Low oil pressure is very dangerous for the engine in these conditions.

Oil Temperature

Another safety-related information, oil temperature that is too high can cause serious damage. It also has a lot to do with the parts you are using as different materials react differently to higher temperatures. In any case, high temperatures are not desirable for any of them. The materials are selected to give reliable performance for the standard operating temperature. If it is higher, this will be a problem and especially so in racing conditions.

Engine Knock Sensor

This sensor lets the ECU know when detonation happens. In this case, the ECU will adjust engine operation in a way that it prevents detonation and keep the engine safe. In most cases, this means it will retard ignition timing to save the engine, also limiting performance in the process. You cannot simply ignore the information from the knock sensor as detonations can destroy engines really quickly.

Nowadays, we can control knock within each engine separately. A good data log provides us with the exact information about when and where it occurs and we can detune it in those specific conditions, keeping the top state of tune in all others. This is a great example of keeping performance as close to the top level as possible while also ensuring safety.

While most tuners who do not develop tuning files based on data logging will not inevitably destroy your engine, they will reduce the chance of that happening by limiting performance. Simply put, without data logging, they cannot know how far they can go in any specific set of conditions, so they cannot make use of the full engine potential.

Exhaust Gas Temperature (EGT)

EGT is very important as it shows you at which temperature the combustion occurs. As each cylinder is monitored separately, this means we can make all of them work evenly which is, once again, very important for both operation and reliability.

As exhaust gas temperatures are measured with every exhaust stroke for each cylinder, monitoring this aspect can help pinpoint very specific conditions very precisely.

For example, if we detect an intense increase in pressure within the cylinders combined with a drop in exhaust gas temperature, this means we have just detected detonation.

Exhaust Back Pressure

Exhaust back pressure is very important for a number of reasons. First of all, on stock cars it shows the condition of several different parts, including turbocharger, wastegate and even the engine itself. It is also a good way to determine if the exhaust needs an upgrade to keep up with other hardware upgrades within the system, although a good tuner should know this even without this information.

How to Perform Data Logging

The described aspects are just a few of many others that are found in a data log. If you are interested in knowing how you can perform data logging on the road or on dyno, which channels are necessary to log and how the data is presented, you can find more information in our page dedicated to data logging.

If you want to learn about which are some of the best tools that are used for data logging and how special tuning projects are managed (a big part of which is data logging), you can find the information here.

Of course, if you need our help with any step of the way, you can contact us directly via WhatsApp or Skype or through our special ticket support system where you will find one of our engineers directly answering your questions.