20G=compressor wheel size... The 20G has two variations, a 20G with a td05h exhaust wheel that is usually clipped 20-25 degress or so or a TD06H/20G.
The TD05H exhaust wheel is in the 16G and 14B turbo's.
Like mentioned above Garrett turbo's have NUMEROUS wheels, housings etc...In Garrett terms a .50a/r .61a/r is what they use to determine Exhaust housing size's and mitsu uses 7cm, 8cm etc..For example the turbo in my car has a t3 high flow exhuast wheel, (there's also just a t3performance wheel you can purchause) with a 50 trim compressor wheel matted in a T04e compressor housing. There's an optional t04B housing with this setup. You see how complicated it can get. With garrett turbo's there a much more wide selection of wheels, housings etc... to be matched together. Matching up the ones that work well together with your engine size is the key.
