![]() In today’s performance market, two types of intercoolers prevail: air-to-air and air-to-water. ![]() ![]() Today, many quality manufacturers offer upgraded bearing systems, including the Turbonetics ceramic ball-bearing unit, which eliminates the traditional thrust bearing allowing the turbo to withstand "up to 50 times the thrust load capacity, compared to a conventional unit." Many other manufacturers have also upgraded to ball bearings systems, including Garrett, to help reduce drag and increase a turbocharger’s life. Traditionally, a CHRA will house two bronze full-floater bearings and a separate bronze thrust bearing. If you have ever heard of someone "rebuilding a turbo," they are most likely talking about replacing the bearings, which can start to wear based on a variety of factors including oil condition, axial loads, or shaft movement. With turbine shaft speeds in excess of 100,000 rpm, the bearing’s job is much, much more difficult than that of a traditional camshaft bearing, and as such turbo manufacturers have spent a lot of time and money building serious bearings to handle these jobs. Of course, holding the housings together is child’s play compared to the real job of the CHRA, which is to support and lubricate the turbocharger’s bearings. Practically, the CHRA serves as the mounting point for both housings and must be made of substantial material to handle the heat and stress of the turbine. The CHRA may not get a lot of ink time, but it is one of the most critical parts of any turbocharger assembly. As the wheel spins, it takes ambient air, rotates it 90 degrees along the blade of the wheel, and forces it into the compressor cover, where it is collected and then forced into the intake tube. Again, to fully understand this process, we would need to explain several laws of thermodynamics, including the ideal gas law, but for our purpose, understand that a compressor wheel’s job is to gather fresh air and compress it-simple as that. This process creates pressure in the intake tract, which we call "boost" and is the reason anyone would install a turbocharger in the first place. Since it is connected directly to the turbine wheel via the turbine shaft, the compressor wheel rotates at the same RPM as the turbine wheel and, as the engine and turbine wheel accelerate, so does the compressor wheel. The compressor’s job is to, quite literally, compress fresh air and funnel it towards the throttle body. Like the turbine, the compressor section is made up of two primary components: the compressor wheel and the compressor cover. ![]() For now, we’re going to cover the basics of turbocharging by looking at each component, defining its purpose, and explaining the theory behind its operation. In this first article, we hope to establish a baseline vocabulary and a working knowledge with which to build off in the future, so if you’re an advanced turbo guru who is looking for tips reading compressor maps or tweaking turbine housings for your exact application, fear not-those stories are yet to come. To put it bluntly, this is Turbochargers 101-A and covers the very tip of the iceberg, from 1,000 feet away. Now, we understand this is a lot to cover-enough to write a book on-but the goal of this particular article is to get everyone, including readers who haven’t ever seen a turbo before, up to speed on the concepts involved. The objective here is to convert the energy contained in your exhaust stream, which would normally go to waste, into positive pressure within the intake manifold, forcing air into the engine and thus producing more power. Look, all technical mumbo-jumbo aside, turbocharging is actually a pretty simple concept.
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