http://www.turbofast.com.au/GTseries.html

According to this link the compressor side has two wheel dia. I am still reading corky bells book, but how can it have two different sizes? What are they referring to? Or are they trying to say that you can get that turbo in two different sizes?

 

There are two dimensions when reffering to a turbos both compressor and turbine wheel. The major diameter and minor. Its also known as the inducer and exducer diameters. the compressors inducer (or minor wheel diameter) is the portion that you'd see looking at the intake of the turbo. this is were air is "induced" into the turbo. The second portion of the wheel is the exducer (or major wheel diameter). This is were the air is "exduced" or slung out the compressor wheel into the compressor housing scroll. these two numbers determine the compressors TRIM. Trim is a ratio of inducer and exducer diameters. Trim is inducer divided by exducer squared multiplied by 100. EXAMPLE: A T04S (aka 60-1, T60, T 60-1, t04B 60-1 etc) has a 2.324" inducer and 3.000" exducer. 2.324 / 3.00 = .775, .775 X .775 = .901, .601 X 100 = 60.1. A 60-1 is a 60 trim... hense the name........ Some people comfuse trim as a wheel diameter in milimeters, but this is a incorrect assumption. Trim is exactly what i just dissscribed, a ratio of diameters. the turbine is the exact same as the compressor except the inducer is the major wheel diameter (this is were the exhaust is "induced" into the turbine section, and the minor wheel diameter is the exducer (exhaust is expelled out here).

~Mike......................

 

.775 * .775 = .601 for those who read that and were wondering how .901 became .601 ... great post otherwise

 

Opps, typo, good catch!

~Mike.............