We are firm believers of the importance of testing and data logging when tuning. Our own company offers many tuning solutions and our most premium solution, “Custom Tuning”, includes dyno testing and data logging at the core of the process:

Whether you choose an off the shelf tune, a piggy back option or a full Custom Tune, we suggest you book yourself in at your local dyno and this is why:

1. Knocking, Pinging or Detonation

Have a read of this Wikipedia article for more info. An extract is below:

Knocking (also knock, detonation, spark knock, pinging or pinking) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder does not start off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.

The fuel-air charge is meant to be ignited by the spark plug only, and at a precise point in the piston’s stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic “pinging” sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive.

The worst thing about “knock” is that for the untrained ear, its almost impossible to detect. Your engine could be ready to blow and you wouldn’t even know it. If you have ever heard the phrase “blew the head off the motor” then you know someone who has experienced serious “knocking” or “detonation”.

A good dyno operator will be able to detect this. By observing the dyno chart, using “knock ears” or by using specialist scan tools, these issues can be detected. Here is an example of a car using an off the shelf flash tune:

The data above shows the knock sensor on the car responding to a detected knock. The larger the number, the more severe the knock, hence the deep red. The owner of the vehicle had no idea that this was going on inside his motor. While the car had plenty of power on the road, it was clear that the software that was loaded was not perfected for his particular setup. On a perfectly running motor with a safe tune, you would expect the data to show 0 and be green all the way through and without the erratic spikes.

2. Fuel Pump Failures

Fuel is the most important ingredient in an engine. Without it, you go nowhere. But did you know that is also protects your motor? In a high performance petrol motor, fuel is used to protect the motor from detonating. If the motor starves for fuel while running high boost, there is a risk of serious engine damage. For some cars, a fuel pump on the way out is almost undetectable without specialist tools. Here is an example of a car with a failing fuel pump:

The number on the left is what the fuel pressure SHOULD be and the number on the right is the ACTUAL fuel pressure. Its around 20% short of delivering full fuel pressure. At this point the client was unable to detect or feel the drop in pressure in any way. Only with specialist logging tools was this able to be detected. The fuel pump on this vehicle failed 2 weeks after the test was performed. Luckily there was no engine damage from the failure. Next time we are sure the client will follow our recommendations and change parts when we advise to do so!

3. Air To Fuel Ratio Issues

The Air to Fuel Ratio is quite simply the mixture of air and fuel in the combustion chamber of a motor. There is plenty of information in this Wikipedia article.

While Modern motors have some pretty large tolerances there are some key points to watch out for here.

1. A lean mixture (a higher lambda number)
2. An erratic mixture (quickly changing air to fuel ratio)

A lean mixture can lead to detonation which can quickly destroy a motor and an erratic mixture can indicate a more severe problem occurring within the motor. The table below shows the Air to Fuel Ratio from the car in the above section about fuel pump failures:

The number on the right is what the lambda number (air to fuel ratio) should be and the number on the left is the actual value. As you can see it is quite inconsistent. This inconsistency and “leaning out” of the mixture (where is reads 0.87) was what initially tipped us off that there was a problem with this car.

4. Boost Pressure Issues

We don’t think we need to explain this one, however we will just in case. See this Wikipedia article for more info. As you will all be aware, boost is the magical grey dust that sits inside your turbocharger and comes out in a big grey puff of smoke when things go wrong. On a serious note, boost issues can be some of the more difficult issues to diagnose. Sometimes you may not even know you have an issue, especially if you haven’t sat in another identical vehicle to compare.

Here is an example of a car which had an issue with power loss. It felt “sluggish” and “laggy”:

The number on the left is the “wastegate duty cycle”, which is a fancy way of saying “% of max boost”. The higher the number, the more boost the motor is requesting. The number on the right is the actual pressure inside the manifold. At 1600mbar it equates to around 9PSI. This particular car should be doing at least 12PSI under these conditions yet the car is asking for more and its not getting it!

The cause? A faulty diverter valve. The boost was actually leaking after the turbocharger very slightly and the fault wasn’t audible. Without a little bit of problem solving skill and some comprehensive data logs this client would have still been trying to figure out why his car was so sluggish.

5. Seeing Your Power Gain

While this may be more about showing off to your friends and just pure vanity, there is just something special about seeing your car on the dyno and seeing all of the extra power that it pushes out. Nothing is more exhilarating than seeing the power line rise up above the stock power line. It gives you a taste of what you are about to take for a spin when its unloaded from the dyno.

Tuning isn’t cheap, we know this, you know this, everyone knows this. So when you are getting a tune done, its always a good idea to spend that little bit more to get your car tested and confirm your power gain. Remember, you will usually only do this once, so its a good idea to get it done right the first time.

So there you have it, our pick of the Top 5 Reasons Why You Need A Dyno & Data Log On Your Car.

Contact Us & Book yourself in to get a tune