turbo measurement

[DR BOOST]

what is the correct method of measuring the wheels on a turbo to determine its size. this is starting to aggravate me . there must be some logical explanation to this because i can make a 44 measure out to a 70 on the calipers. also , is there a specific listing of wheel sizes to identify turbos?


TIA

surej

 

[87GN_70GS]

The 44 compressor (T04E 60 trim, Garrett p/n 442476-0017) should measure 2.29" on the inducer and 2.95" on the back disk. The 44 turbine (T3 76 trim, Garrett p/n 442283-3) should measure 2.23" on the exducer and 2.56" on the major dia.