These are both T4 turbos with H compressor cover
Comp 78/75 1.15 a/r T4 housing on the right
Precision PT8847 (88/84) .96 a/r housing on the left
It's pretty obvious the "larger" 1.15 a/r housing on the 78/75 is still pretty tiny compared to the .96 a/r on the 84mm turbine precision turbo