Sorry if this was in the FAQ section....I checked and didn't find anything.....Anyway I am a little ignorant when it comes to turbos...Basically I was wondering if someone could explain the different sizes, how to know which turbo is bigger and which is smaller, for example t3/t4 vs. big 16g....and if someone could also explain trim to me....for example my friend bought a turbonetics t3/t4 57trim for his b16a sir 1...thanks

 

Trim is the size of the compressor wheel, in Millimeters i believe. The bigger the number, the bigger the compressor wheel is. The actual size of the turbo is dependant on A/R spec of the compressor and turbine housings. so when you hear people say .63/.60 or .63 hotside 60 coldside it means the turbine side's a/r ratio is .63, and the compressor side's is .60. When someone says Stage I wheel or whatever, that means the size of the turbine wheel. Higher stage is a bigger wheel. (This was all learned from the book "Maximum Boost" by Corky Bell....you should pick it up.) Oh, and someone plz correct me if i fucked up somewhere.

Cliff notes:
Trim = Size in Millimeters of compressor wheel
Stage x Wheel = Size of turbine wheel
Bigger A/R on housings = bigger turbo

 

thank you...good info