I was asked recently about the purpose of a turbo timer. To answer ‘what is a turbo timer?’ we first need to have a quick look at what a turbo does.
What does a turbo do?
Turbochargers use the flow of exhaust gases out of an engine to drive a turbine to compress air in the intake and force it into the engine. More air means more oxygen which, when coupled with more fuel means a more powerful explosion and so more power out of the engine. They can spin at over 200,000 rpm and are lubricated and cooled by engine oil. Some also have water cooling.
I recommend this video if you’d like a more detailed explanation of a turbocharger.
Why do turbo timers exist? Premature turbo wear!
If a turbocharged car has been driven on boost for any length of time, the turbo can suffer (premature wear) if the engine is switched off straight away afterwards. Shutting the engine off stops the oil feed to the turbo. After a period of ‘spirited’ driving it is helpful to leave the engine running on tickover, to ensure the hot turbo has a continued flow of oil (and coolant if it’s also water cooled) to cool it down.
What does a turbo timer do?
The turbo timer measures how much boost has been used, for how long and how recently in the journey. It is wired in to the ignition circuit or ECU and can ‘take over’ control of the ignition switch. When you turn the ignition off, the timer overrides this and keeps the engine running. It counts down for however long it deems necessary to cool the turbo. If you’ve been pootling around, this will be short. If you’ve just come off the motorway or driven the car hard, it may be several minutes. This time can be a fixed preset amount if you prefer.
Do you really need a turbo timer?
We’ve seen that turbo timers help you look after your turbo. But do you need one? No, you don’t need one. You could just train yourself to ensure you allow the engine to run for a couple of minutes at the end of each journey.
However, looking after the turbo is important. If a turbo timer helps you remember to do the above, I’d suggest it may be a worthwhile addition. Along with regular oil changes with good quality oil.
Are turbo timers relevant if you don’t have a performance car? Yes, they are relevant for any car with a turbo, although they are most commonly found on performance cars.