The automotive turbocharger (as most drivers know them) is used to give smaller displacement engines a boost in power output. They provide smaller size engines the capability of getting them closer in performance and along the lines of their larger displacement counterparts. Turbochargers are also used with most passenger and truck diesel engines to boost horsepower and torque across the engines rev range.
Most of you know the turbochargers basic operation of using heat and exhaust flow from the engine to spin a turbine wheel at high revolutions. Attached to the opposite end of the turbine shaft is an impeller wheel mounted inside the turbochargers compressor housing. The blades on the impeller compress and force air into the engine to help it boost power. A controlled wastegate then opens to vent excess pressure, keeping boost in control at various engine loads. The air exiting the turbo is usually routed through a cooler (similar to coolant through a radiator) and cooled before entering the combustion chamber. As the cooler air is denser, and provides more power while reducing the risk of detonation.
Though turbochargers have traditionally been used as a source of added power, lately, it seems as though they are also being used to boost engine fuel economy. Ford's Ecoboost engines, for example, use a turbo to make the performance of their four cylinder motor comparable to that of a six cylinder, while keeping the four's fuel economy relatively high.
Because turbochargers increase compression and power, they also increase heat inside the combustion chamber. Ultimately, all this operation (if not well maintained) can lead to catastrophic turbocharger or engine failure.
Here are some easy steps to help those of us with turbocharged engines prolong the life of our turbochargers:
1. Change your engine oil regularly and religiously. Turbo impellers reach intensely high speeds and keeping your turbochargers impeller shaft and bearing well lubricated is the first order of business. Most turbocharged vehicles will have a much shorter oil life expectancy than naturally aspirated counterparts, so always be sure to flush out your system with new fluid regularly. On every turbo car I have owned, I was always sure to perform an oil change at least a few hundred miles early for safety's sake.
2. Keep the flow of air to and from your turbo as clear as can be. I have expressed the importance of having a clean intake tract and filter in previous videos. In one, I explained what a dirty filter can do to rob performance from an engine and even showed an example of a poorly kept filter on one of our coworkers BMW 335i.
In his case, those filters were only inches from the turbo inlet starving it with dirty air and hurting performance. Always make it a habit of inspecting intercooler plumbing and filters, making sure nothing but clean air is flowing to the intake.
3. Do not ignore your intercooler. Most turbocharged cars have one, either air to air or air to liquid, help lower compressed air temperatures and introduce denser air in the mixture. Always make a note of looking over your inter cooler for bent fins, debris, or dents. I can't even count the number of stock and aftermarket turbocharged cars I see driving around with crappy coolers.
4. Always be sure to flush coolant more regularly. Most of us, and let's be honest here, don't bother much with this one, as we only ever add coolant when needed, or flush coolant when another repair calls for it, and I'm not excluding myself from this. It is very important especially in turbocharged cars to keep heat at an absolute minimum. Flush your coolant regularly, as most turbo cars will have lines leading to and from the impeller shaft housings that are used to maintain cooler temperatures.
Turbocharger failures are often the result of poor lubrication or oil breakdown. The high temperature in the turbo exhaust housing transfers a lot of heat to the shaft bearings in the center housing. If the supply of coolant or oil to the turbo housing is restricted or lost, it can cause bearing failure. Synthetic oil is recommended for turbo engines because it can handle higher temperatures better than conventional oil.
