Turbine shaft size
 

I have an s4 hybrid turbo using the stock turbine wheel. I've been looking for a new compressor wheel and they all say either big shaft or small shaft. Is the stock turbine wheel considered a big or small shaft? Also just curious what are the actual sizes of the 2 shafts. Thanks.

I have never built a hybrid turbo before, but I know for a fact the stock turbine wheel is not a Big Shaft.

small shaft, standard T3

Standard T3/T4 sized (both have same diameter). Virtually any T3 or T4 compressor will slip onto the shaft. Hybrids are pretty easy to build, you just have to know what to look for when assembling them (like you just can't bolt the shit together, oil passages need opening up and some holes such as a T4 back plate are ever so slightly off. Also wastegate mounting needs some tweaking and adjusting).

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