Got a turbocharged car? Here are the things you need to worry about, and the things that you don’t

Does your car have a turbocharged engine? If so, there are things you should do to protect it. With more components and a more complex design, turbocharged engines are a little different to their naturally aspirated cousins – which means they benefit from a bit of special treatment when it comes to driving and everyday care.

In this week’s article, we look at six ways to protect your car’s turbo engine from harmful wear and tear, including maintenance advice and driving tips.

1. Regular Oil Maintenance

Oil (and changing it regularly) is already critical to an engine's longevity. It's invaluable to the life of a turbocharger. The firsts turbos were solely oil-cooled, supplied by the engine's oil. Today's turbos are additionally cooled by coolant—but are still harsh on oil.

Let us remember that turbo systems comprise of moving parts which rotate at incredibly high speeds and work under intense heat and pressure. This means that they need a constant flow of quality engine oil to lubricate the compression valve and intake and outlet fans, to reduce wear and help them perform at their best.

Consult your manufacturers handbook to see the recommending servicing schedule, as well as the recommended grade of engine oil. If the manufacturer’s is long gone, I would suggest changing the oil every 7500 Kms with a high-quality, fully-synthetic oil. Remember to check that the API type is correct for your car’s engine.

2. Warm Up the Engine

While providing your turbo with fresh oil frequently is a good start, once it's in your engine — you also have to use it properly. Oil functions its best within an optimum operating temperature. It flows and lubricates the best when around 90 to 105 degrees Celsius. Prior to that, its thicker state and lower viscosity increases oil pressure—putting more strain on oil seals.

The seals of a turbocharger are located in its central cartridge, where oil lubricates the shaft that connects the turbine and compressor sides. When these seals wear enough to let oil seep excessively (a bit of oil "blow-by" is normal in a turbo with some use), you may see excessive blue-like smoke from the exhaust.

Getting the oil up to temperature also burns off moisture that builds in it while it sits cool in the oil pan. Quick, short trips taken frequently will necessitate an oil change sooner because the fluid will become saturated with un-burned impurities.

Each time you get behind the wheel when your car’s cold, keep in mind the engine oil warm-up time, and change your driving style accordingly. Being too aggressive with your right foot places a massive amount of strain on the oil pump, which has to dole out more pressure to circulate the thick oil through the system. Thick oil is also ineffective at properly lubricating moving parts, which can cause problems in the turbo system.

For the first 10 minutes of driving a cold car, go easy on the accelerator pedal to limit the strain on the oil pump and prevent unnecessary wear and tear on the turbo system. Wait at least 10 minutes before going full throttle or watch the oil gauge for when it’s reached its optimum temperature.

3.     Cruise Right

Having a turbo system in your car might sound exciting, even if in most cases (read modern eco-friendly hatchbacks) they’re only there to make up the power lost from having a low-capacity engine. For this reason, it’s important to be aware of the limits of your car’s turbo system and avoid overdoing it by being overly aggressive with the accelerator.

When cruising around town or on a high-way, try your utmost not to jab the accelerator. Instead, ease the power on slowly to give the turbo a chance to start spinning freely, and use the accelerator sparingly to maintain your speed. While turbos are rigorously stress-tested, and should last the lifetime of the engine, regular bouts of aggressive driving could take their toll, and cause costly issues.

Not only will gentle cruising increase the lifespan of your turbo, it will give you great fuel economy, too.

4. Work the Gears, Not the Turbo 

While a turbo system gives even the smallest engines plenty of power and torque, you should still downshift when overtaking, and not rely solely on the turbo for all of the car’s accelerative performance.

If you have control of the gear selection in your car, selecting a lower gear overtaking or climbing a hill can spare the turbo doing all the work.

Being a gear or two lower reduces the number of times you have to utilize maximum boost pressure—whether for short bursts or relatively longer. Regularly keeping the turbo howling to avoid a downshift up inclines can, quite literally, pop your turbo-bubble.

A lower gear places your engine further into its "power band," the span of RPMs in which it works the most efficiently. In those ideal engine-speeds, less throttle (and boost) is required than in higher gears. There's more to a turbo car than just the turbo, utilize it.

5. Let the Engine Cool After Driving

Just as you need to warm up your engine, you need to let it cool down. Extended journeys and high speed driving creates a lot of heat in your turbocharger, so don’t turn your turbo car off immediately.  You should rather leave your engine running for a couple of minutes to cool down and circulate the oil before switching the ignition off.

The reason for this is because of that lifeblood-oil coursing through it. If it's not given proper time to circulate and cool, the oil cooks into sludge—and clogs the oil channels. When sludge blocks the cooling channels of the turbo, insufficient lubrication will wear its bearings faster.

A minute of idling time after a 20-30-minute drive is a bit of added prudence (two minutes after a particularly long or hard drive).

6.   Use The Correct Octane Fuel 

Certain turbo cars may specify a particular high-octane fuel be used to prevent knock. A turbocharger’s job is to cram more air into the combustion chamber, and as the piston moves up, the air is compressed which drives the pressures and temperatures up. If the temperature gets too high, the fuel in the chamber will spontaneously ignite. This is called knock, or premature detonation, and it can cause serious damage.

You should always follow the manufacturer’s recommendations. Some manufacturers are more lenient and allow lower octane fuels, as  many turbo’s now have advanced computer-controlled wastegates, individual ignition coils for each cylinder, and high-pressure direct-fuel injection which allows the engine to control ignition much more precisely. Fuel can be injected exactly when it’s needed in the engine and even in several waves during combustion for maximum output and efficiency, all while the liquid petrol cools the intake air charge.

Modern Turbo’s

As we mentioned last week, turbo’s have become increasingly popular, as well as significantly more technically-advanced in the last few years.

The demographic of turbo drivers have also changed. In the old days, turbochargers were found in performance cars, and their owners were predominantly petrol heads who were well-versed in how to and not to drive a turbo. Nowadays, you can find a turbo in every market segment from budget hatches to large family vehicles to mom’s taxi. This means that many people are sitting behind a turbo engine, who may not know any of the advice list earlier. How are manufacturers okay with this? Will failure to follow this advice really cause damage to modern cars, or are all these tips outdated with the rise of modern technology?

What the Manufacturers are saying

Autocar posed this question to several manufacturers. The general consensus from manufacturers is that modern cars are tested to such extremes that there’s not much you could do to a new turbocharged engine that would cause any problems. For older cars, say ten years or older, many of the tips given above are true, but today, software systems are such that they neutralise any driver input that could start shredding internals under the bonnet.

For interest sake, here are a few of the recorded responses:

BMW

“Historically, we would provide advice on turbo cars. However, we no longer suggest specific tips to our customers who drive these cars.”

AUDI

“Contemporary turbocharged Audi engines don’t require the special precautions or operating procedures that were necessary for older units…But we do of course recommend that owners observe the general guidelines for minimisation of wear and tear, and also of emissions, which are essentially applicable to all engines.”

CITROEN

“There has been a lot of advances in engine management technology and turbochargers over the years. THP performance engines are fitted with separate cooling systems to help heat soak, so there’s no need to leave engines idling to dissipate heat – the system automatically operates when the vehicle is switched off. Electronically controlled turbos help control loading on the engine and turbo, so can better manage driving style and power demands.”