• engine

What is turbo lag?

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Updated 10 Oct 2019

Rowan Johnstone

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Before we can answer the question of “What is turbo lag?”, it would be handy to know what a turbo is and how it works.

Very simply put, a turbo - or turbocharger to give it its full name - is a device that increases an engine’s horsepower and efficiency by forcing extra compressed air into the engine.

What causes turbo lag?

For the turbo to force compressed air into the engine, it needs to gather the exhaust gases to spool its turbines and build up the pressure.

The process of spooling a turbo takes time as the engine increases its RPMs forcing more and more exhaust gas pressure into the turbocharger.

If you’re driving a turbocharged car travelling at low RPMs in a cruising situation, putting your foot down won’t give you instant results from the turbocharger, as turbo lag is more obvious at low RPMs.

However, as your car increases its RPMs, your turbo will spool to the point where it builds up enough compressed air and forces it into the engine, resulting in increased power output.

Why can’t standard turbochargers operate at a lower RPM to avoid turbo lag?

The way turbochargers operate can be best described as a happy medium.

If a turbocharger is small enough to spool and make power at low RPMs, it simply would not be strong enough to handle full throttle and higher RPMs.

These small turbochargers could explode due to the force and cause some serious damage inside your engine bay.

Larger turbochargers that are not matched to the RPM range of the engine will most likely not be making any boost until well into the engines powerband.

Although peak power will be increased, your turbo lag will also be more pronounced as your RPMs will need to be much higher in order to spool and engage the turbo.

In most cases, the specific turbocharger for your car has been built to engage right in the middle of your engines powerband, in order to safely and effectively deliver the increased power output.

Additionally, some modern, high performance vehicles will come fitted with technology such as a Twin-Scroll turbocharger, which aims to remove turbo lag completely.

Whilst turbo lag is to be expected in turbocharged cars, if you suddenly experience an unusual amount of turbo lag in your car or a drastic loss of power, this could be a sign of a problem with your turbo.

If this is something you’re experiencing, be sure to get your car booked in with an expert mechanic on AutoGuru.

It’s the easiest way to find local, high-quality mechanics who you can easily book online!

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Written By

Rowan Johnstone

On weekdays Rowan can be found in the AutoGuru office, driving content and growth with the rest of the marketing team.

On weekends you’ll probably find him in the garage with his dad restoring a 1958 Ford Star Model Customline or enjoying a cruise through the Gold Coast hinterland on his Suzuki GSX-R600.

Despite his passion for being behind the wheel (or handlebars), he looks forward to the day when he can commute to work in his own driverless car.