Turbocharged vehicles can perform better as turbos utilize exhaust gases to provide extra energy. However, because of how they work, turbochargers don’t provide an immediate boost since there’s a delay in the acceleration response, leading to turbo lag. But what is turbo lag?
To understand turbo lag, you need to know the mechanism and how it boosts the engine’s power. So, here we will discuss the concept of turbochargers and the occurrence of turbo lag, which is specific to turbocharged vehicles.
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What Is Turbo Lag?
Turbo lag is the delay between stepping on the gas pedal and the boost delivery to the engine. The delay happens because the turbo needs a moment to spin up and produce the added air pressure that would eventually act as a boost to the engine.
The turbocharger relies on the exhaust gases to spin, and it takes a moment for them to generate enough energy to make the car accelerate faster.
Not all turbochargers have the same amount of lag. Different designs lead to different delay periods, with some modern turbos being able to almost completely remove the lag.
Meanwhile, older turbocharger models have a longer delay due to their simpler designs and technological limitations.
How do turbos work?
Turbochargers work by converting exhaust gases from the engine into additional energy that the car can use. Most commonly, they find use in economical cars to further enhance their cost-effectiveness and large vehicles with big motors to improve the power output for performing heavy-duty work.
Unlike superchargers, which source their fuel directly from the engine, turbochargers use exhaust gases to spin a turbine, which powers the compressor to work.
The compressor compresses air and adds it to the fuel-air mixture in the combustion chamber. The additional air improves the combustion process as it allows for the fuel to burn completely and produce more engine power.
However, the turbine needs time to reach the right speed to generate enough air pressure. This is why turbochargers are better at generating power at higher engine speeds, i.e., when the exhaust gases are stronger and when they spin the turbine faster.
What Causes Turbo Lag?
The engine is a complex group of components working in sync with one another. Turbochargers have to integrate into that system as they use waste energy to power their work. That means they are reliant on the harmonious work of all components in order for them to be fully functional and productive.
The factors that contribute to the amount of turbo lag are the following:
- The time that exhaust gases need to build up energy
- Inertia
- Delays in air-fuel mixture delivery
- Design
- Engine size
Bigger turbochargers produce a bigger boost, but they also need more time to build up the necessary volume of exhaust gases to spin the turbine. That’s why a bigger turbo doesn’t mean lower lag.
In contrast, smaller turbos tend to generate less lag because they have lower inertia and require a lower volume of exhaust gas buildup to reach their optimal spinning speed.
Overall, it's essential to remember that turbo lag is a consideration regardless of the bought turbochargers.
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How to Fix Turbo Lag
If the turbo lag is too long, it can have adverse effects on the driving experience and cause frustration for the driver. In heavy-duty vehicles, where power delivery is crucial for towing or similar work, an excessive lag can be the reason for failure to perform the task.
In such cases, installing a new turbocharger is always an option, albeit an expensive one. At some point, you may realize that the old and outdated turbocharger cannot service the demand for additional boost.
If your turbocharger lags because of a malfunction, you should have your car inspected as soon as possible. The symptoms of a broken turbocharger that could accompany a prolonged lag may include:
- Excessive smoke
- Unusual noise
- Oil leaks
- Inconsistent boost pressure
- Too high exhaust gas temperature
- A smell of burnt oil from the exhaust
Driving Techniques to Optimize Turbo Lag
One way to reduce turbo lag significantly is by optimizing your driving. Altering the driving technique to make it more suitable for the capacity of the turbocharger is an effective way to improve the driving experience. Not only will implementing optimized driving techniques reduce the turbo lag, but it will also improve the engine performance, responsiveness, and fuel efficiency.
So, here are some techniques how to reduce turbo lag:
- Keeping the engine RPM high
- Downshifting before acceleration
- Avoiding sudden throttle charges
Instead of suddenly downshifting, you can also keep to lower gears to increase the engine speed. Moreover, while you are still at the low end of RPM, gradually work toward the higher end without sudden bursts.
Implementing these tips will maintain a high boost pressure, increase the engine speed when needed, and prevent boost fluctuations.
How to Choose an Optimal Turbocharger
The best way to fix turbocharger delay is to avoid it by choosing a modern turbo that is compatible with the engine. The turbo size and design have to fit the engine displacement and be in line with the power output.
Furthermore, it has to be optimized to provide the ideal balance between low-end torque and high-end power.
Newer versions of turbochargers have anti-lag systems that inject fuel directly into the exhaust manifold to keep it spinning between gear changes.
On the other hand, electric turbochargers don’t even use exhaust gases to power themselves. Instead, they use an electric motor, which eliminates the turbo lag.
An important thing to consider is your personal goals with the car. If you drive a small, economical car, then you need a small charger that spools fast and provides a needed boost at lower RPMs. If you drive a bigger car, then you will need a bigger turbo to be able to respond to the demands at higher RPM.
For more powerful cars, there are turbos with designs that either have two turbines or divide the exhaust into separate channels.
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Summary
What is turbo lag? We have explained it and the different situations it occurs in with different types of vehicles and turbochargers.
The causes of turbo lag are mostly related to the time it takes for exhaust gases to spool up the turbine of the turbocharger to generate power for the compressor. Additionally, inertia can further prolong the delay.
Technological advances have enabled cars to have lag-free turbochargers that run on electricity.
Smaller cars require smaller turbos that generate a boost at lower RPMs, improving their cost-effectiveness. Conversely, bigger cars require larger turbos to deliver boosts at higher engine speeds and improve performance.
