5 Things You Should Never Do In A Turbocharged Car
With car fuel efficiency going up and car companies resorting to shedding weight to stay competitive, turbocharged engines are a lot more common place than before. With that increased power density and efficiency comes different engine behavior and also more equipment that could potentially fail on you. Therefore it is critical to remember these 5 tips so that you can prolong the life of your turbocharged vehicle. Jason Fenske of Engineering Explained has made a very thorough video explaining the science of what’s happening in your engine as it’s running:
1. Do not run the engine hard after start-up.
"Most people know you should let your engine warm up before running it hard, but many cars only have coolant gauges. Engine oil tends to take longer to heat up, because you don’t have a thermostat like the coolant does, which isolates the coolant in the engine block and regulates its temperature. Oil that isn’t heated up won’t flow as fast as oil at operating condition, which means you’ll have less protection at engine start up. This is especially true for turbocharged vehicles, because you also have oil feeding the bearings of the turbocharger, which spins at insanely high RPM and produces significant heat, so you want to make sure you have proper oil flow through the turbo. It will be different for every car, but it could be an additional several minutes before your oil temperature is near your engine coolant temperature."
2. Don’t shut the car off immediately after running it hard.
"You’re going to have hot spots where the engine components, and especially the turbocharger, are still significantly hotter than your engine oil temperature. If you shut off the engine, the oil no longer flows, and thus pockets of the oil are going to be heated up to very high temperatures. These high temperatures break down the oil, and also burn up and evaporate the light end of the oil, leaving behind a heavier oil that won’t have ideal flow characteristics. This reduces your engine oil life, and also means you might have less protection at start-up."
3. Don’t lug the engine.
"Low Engine Speed, High Load Operations. First, this isn’t ideal because you’re telling your engine to move your vehicle quickly when it’s at a huge gearing disadvantage. Second, when your engine tries to produce more power at low engine speeds, it may be able to inject more fuel, but not ingest enough air. As a result, you’ll have a highly rich mixture and this can lead to poor emissions, damaging your catalytic converter, and seeing black smoke come out your exhaust. Third, regarding damaging your engine, this can cause low speed pre-ignition. LSPI is a when you have pre-ignition of your air fuel mixture (before your spark ignites it) and is becoming a more common phenomenon with small turbocharged engines running at low engine speeds with high load. It’s a dangerous condition that can cause engine damage, such as broken spark plugs or cracked pistons, as a result of extremely high pressures which occur due to significantly advanced ignition timing. It’s also very challenging to detect, and can’t be avoided through ignition timing or changing the spark plug’s heat range."
4. Don’t use low octane rating fuel
"Especially if the car has been modified. Turbocharged cars tend to have higher pressures and temperatures within the combustion chamber, which is why they have reduced compression ratios to compensate. If your car is modified, you can keep it reliable by running a rich mixture and using high quality, high octane fuels. Obviously reducing boost and retarding the engine timing will do this as well, but of course you’ll be reducing performance. There are knock sensors to help minimize any engine problems, and so they’ll retard timing if it senses knock will occur."
5. Don’t floor it coming out of a corner.
"In this one I just wanted an excuse to talk about slip angles. Turbocharged cars have some varying amount of turbo lag, new ones are much better. My point is this, as you’re coming out of a corner, your tires have some loading on them, whether your car is FWD, RWD, whatever. Now this doesn’t apply to AWD quite as much, but it’s still an issue. Your car’s stability is a result of your front tire slip angles being nearly identical to your rear tires slip angles. So long as this is true, your car moves on its targeted path. If you floor a turbocharged car, especially cars with high amounts of turbo lag, you get slammed with torque fairly surprisingly. This shock of torque increases the demand of the driven tires, increasing their slip angle. If you have a significant increase of slip angle of just one set of tires, front or rear, you end up with understeer for FWD, or oversteer for RWD. All of this is to say that your throttle application exiting the corner is very important, especially in 2WD turbo vehicles, where turbo lag can easily cause an understeer or oversteer situation."