To Idle or not to idle?

Turbochargers– the magical-exhaust-power operated component, that adds an extra liveliness to the engine. These are mostly used by commercialised companies to ply to the stringent exhaust rules. However, having a turbocharger requires a really important operation- idling– before shutting down the engine. Or does it?

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The exhaust gases are the pwerhouse of the Turbos!

Some facts to be understood are, while an engine runs at an RPM of 4000-5000, a turbocharger runs at RPMs around 150,000.This keeps the turbo running even after we shut down the engine.The other factor to be considered is the temperature at which the turbo operates, the temperatures in turbos without an intercooler can be around 150 degrees.

 

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Ford RS 200. Yeup, even rallying mastered this black magic.

 

These factors create an issue as most of the mass produced cars are oil cooled. The problem with oil is, if it is not properly cooled, oil “cooking” occurs. This “cooked” oil forms solidified oil deposits which eventually go on to block the oil passages. Oil “cooking” happens when the engines is killed suddenly after a hard run, as when the engine revs are high, the turbo is also running at high RPMs and extremely hot temperatures.

Killing the engine under these conditions would mean killing the oil pump while the turbo would still be rotating because of its inertia .So now we have a hot running turbo with no circulation of oil which “cooks” up the oil.

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A Toyota 7s heavily tubocharged rear end!

A hot shutdown is thus the worst thing you can do to your turbocharged car and is the most common reason for premature turbo failure. Considering the above factors, it is obvious that we need to idle our car. But some cars nowadays, feature water-cooled turbos. These turbos don’t require a cooldown period but such turbos feature only in high-end cars, nevertheless, following the idling rule wouldn’t hurt our pockets so much. Make idling a habit, if you own a turbocharged car.

Here’s a small compilation to fill your heart with noises of wastegate and turbo- spooling! Braaap-Stu-Stu-Stu!

-Akshay Dua

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