When car enthusiasts get together, the topic of conversation soon comes around to turbochargers or turbos as most call them. This is because a turbocharger can greatly increase a car’s horsepower without adding much weight. A turbocharger like the GT35R increases horsepower by increasing the amount of fuel and air available for the engine to burn. In general, turbos account for a large part of the aftermarket car-accessory business. The T35R is manufactured by several companies; it is also referenced by several other names such as GT35R, GT35/40 and GT3582R. The "R" at the end of the name means this style turbocharger uses a ball bearing cartridge.
The GT35R Turbo is comprised of three parts: a compressor, a turbine and the shaft that connects the compressor to the turbine. The compressor intake, which supplies the air for the turbocharger, is 4 inches in diameter. The outlet is the direct connection of the air intake to the compressor and measures 2.5 inches. The compressor trim is .70 A/R (the "A/R" is an abbreviation for area divided by radius.) Generally, the higher the A/R, the more powerful the turbocharger is.
Trim is a term that describes the ratio of the air inducer to the air exducer in both the compressor and the turbine. It is the air ratio and is expressed as “ar.” The inducer supplies the compressor wheel with air from the intake, and the exducer is where the air exits the compressor wheel into the turbine.
The GT35R Turbocharger has an 84 ar trim size. Its turbine wheel is 2.12 inches. The turbine housing size can be 0.63, 0.82 or 1.06 A/R depending on the car that will receive it. The smaller the turbine ar is, the more efficient it is. The turbine wheel diameter is 3.1 inches.
The shaft, or center housing/hub rotating assembly (CHRA), has ball bearings. A CHRA has either a thrust bearing or ball bearings lubricated with pressurized engine oil. According to Air Power Systems: “Traditional turbocharger design employs a conventional plain bearing that runs on a film of oil. This is known as a floating metal bush. The GT35R turbocharger shaft gets support by two ball bearing assemblies. These again use engine oil, but no longer rely on a thin-film of oil over a wide area to support the turbocharger shaft.” The ball bearing design uses less oil and generates less heat than a thrust bearing design. Since, the ball bearing type turbo has such tight clearance between the bearing and shaft, the thrust load capacities increase up to three times more than by the thrust bearing shaft. The shaft is both water- and air-cooled.
