I have a t4 with .7a/r compressor and .5a/r turbine.....any ideas what this is? I was told its a t70 but i dont think so. would i have to measure the compressor wheel to know for sure?

 

Yeah, you would have to measure the overall diameter of the compressor wheel, and the diameter of the inner fins (inducer and exducer). The specs for a T70 should be available somewhere on the web, just compare your numbers to those. Post up some pics of it too.