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When is water-cooling setup necessary for a turbocharger?
Every turbocharger has different cooling setups by default. Oil-cooled and water-cooled turbochargers are two common types of turbo cooling systems. In general, you see turbo with only oil-cooling system on journal bearing turbocharger, although this does not apply to all of the journal bearing turbos; some journal bearing turbos have both oil and water-cooling systems. However, due to their mechanical design nature, all ball bearing system turbos are basically required to cool by both oil and water. Below we’ll discuss about water and oil cooling differences and their various characteristics.
Cooling Method
As turbochargers operate under high temperature, cooling during operation is very crucial for lifespan of the turbo parts.
Oil-Cooled Turbocharger:
In an oil-cooled turbocharger, the engine oil is used to cool and lubricate the turbo's internal components, particularly the bearings. The engine oil circulates through the turbo and absorbs heat generated during operation. Over time, excessive heat can degrade the oil, reduce lubrication efficiency, and potentially damage the turbo.
Water-Cooled Turbocharger:
Water-cooled system turbo use both oil and water to cool down the temperature. Oil lubricates the parts and also cools down the temperature like the oil-cooled system, but with water-cooled turbocharger, it has a separate coolant system (coolant mixture) to dissipate heat. The coolant circulates through the turbocharger water jackets and extracts heat more effectively than oil-cooled system alone. The coolant system helps prevent overheating, ensuring more stable operating temperatures and longer turbo life.
Turbo Longevity
<Vehicle:2013 Ford Focus ST3 /Turbo:KURO GTX2867R Gen2 /Source:IG @bro_chacho_st3>
Turbocharger lifespan is one of the factors to consider when choosing a new turbo. Longer turbo lifespan saves you the hassle for part repair. Oil-cooled system and water-cooled system also affects turbo lifespan.
Oil-Cooled Turbocharger:
Oil’s thermal capacity is lower than water’s, therefore oil-cooled system turbos ten to wear out faster under extreme heat conditions. Overheating can lead to premature bearing wear, turbo failure, or oil coking, meaning to form carbon deposits inside the turbo.
Water-Cooled Turbocharger:
Water-cooled turbos last longer in performance applications and heavy-duty environments because the additional cooling reduces stress on the internal components, thus extending the lifespan of the turbo.
Applications
Like every turbo setup options, each option suits different needs, and that’s why some turbochargers have default setting of only oil-cooled system while others have default settings of both oil and water-cooled systems.
Oil-Cooled Turbocharger:
More commonly used in less-demanding, low-boost, or older turbo setups. Ideal for lower power applications where extreme temperatures aren't a concern.
Water-Cooled Turbocharger:
Commonly found in modern, high-performance vehicles or applications that demand sustained high boost levels and longer duty cycles, like racing or heavy towing. Water-cooled systems are often favored for their reliability in high-stress environments.
Complexity and Maintenance
<Vehicle:Subaru WRX /Turbo:TD06SL2 20G /Source:IG @baxleysspeedshop>
Complexity of the parts and structure influences maintenance for the turbocharger regardless of which cooling system.
Oil-Cooled Turbocharger:Oil-cooled system turbochargers have simpler cartridge structures; therefore, they have fewer components since they have no separate cooling lines, making them easier to install and maintain. However, they require more frequent oil changes and careful monitoring of oil quality to ensure their cooling efficiency.
Water-Cooled Turbocharger:Water-cooled system turbochargers on the other hand have more complex structure as they require both oil and coolant lines. This makes the initial installation more costly and more complex as well as the need for more complicated maintenance. However, these are offset by longer turbo lifespan and better overall performance.
Performance
Depending on the performance targets and requirement, you may choose the suitable bearing cooling system for your ride.
Oil-Cooled Turbocharger:Sufficient and suitable for lower boost applications, but performance may likely degrade at higher power levels due to overheating.
Water-Cooled Turbocharger:Better suited for high-performance applications, additional cooling allows the turbo to maintain consistent performance over longer periods without risking damage.
It’s obvious that water-cooled turbochargers are the better choice for modern performance vehicles due to their superior heat management leading to better durability, while oil-cooled turbos remain popular for simpler and less demanding applications.
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