If you bring your car to a dyno tuner, you're probably looking to unlock as much power as possible from your engine modifications. Dyno tuning is an excellent way to release this potential, but do you know what the tuner is doing once they put your car onto the platform? Tuning involves several complex steps, but a surprising amount of it comes down to one thing: maximizing airflow efficiency.
The Importance of Airflow
You've probably heard tuners tell you that your engine is essentially a large air pump. While your fuel stores energy, you can't burn that fuel without oxygen. Air intake is often the limiting factor behind power generation on a gasoline engine. Forced induction systems such as turbochargers and superchargers are one approach to pull more air into an engine.
On the other hand, fuel is mostly a reactive element. Your vehicle's ECU attempts to supply fuel to your engine based on your engine RPM and the amount of air it can pull into the combustion chambers. As a result, making more power often means increasing the amount of airflow into your engine and tuning your ECU to supply adequate fuel under these conditions.
Volumetric Efficiency Explained
The volume of your car's cylinders is one of the primary limiting factors in how much air your engine can utilize. Volumetric efficiency measures how well your vehicle uses that volume and makes oxygen molecules available for combustion. Airflow efficiency and volume will change across the RPM band when you modify your engine.
To create an appropriate fuel map for your engine, tuners use volumetric efficiency (VE) testing to determine how your modifications have altered these values. Fuel mapping is essential to ensure that the engine maintains a proper air/fuel ratio. Without this mapping, your engine will potentially run too lean or too rich, resulting in drivability issues along with reduced power and efficiency.
How VE and Tuning Go Together
While tuning can have a few different outcomes, most tuning strategies involve optimizing the amount of fuel injected into an engine at specific RPMs and engine loads. In other words, your engine's VE will change based on how hard you're smashing the gas pedal and how fast your engine is already turning. These factors determine the ideal amount of fuel to supply.
By measuring VE, dyno tuners obtain the critical piece of the puzzle they need to create a fuel map that maximizes the gains you'll experience from your car's mods. This information allows them to create a customized profile for your vehicle, ensuring you get the best performance and the best bang for your buck out of your modifications.