The smaller compressor housing is probably restricting flow. It wouldn't surprise me if it had a poor diffuser for that wheel.I previously had a COMP turbo , ball bearing, water cooled, 80mm compressor wheel with 79 straight cut exhaust wheel, with a 0.96 undivided housing. The compressor housing of the comp turbo is smaller. It spooled up dang fast, but for 80mm compressor and for what I am looking for, it just didn't seem to match my combo.
I drove my G-ride a good bit the other night. I was actually impressed with how quickly this turbo come up on boost. I feel real decent about the turbo at the moment. That being said, I need to get to the track where I can get some good data logs that will allow a proper quantitative comparison of spool up and performance. It is real humid in south MS in August, and I don't like beating the car up in this poor air, so I am planning on many September track outings. For now, I just have my seat-of-pants reaction which is impressed for sure.
I went 152 on the Comp 76 billet wheel with the 75mm exhaust wheel, but it did have a bigger compressor cover.
The A/R is advertised as a 1.30 but its based on a T4 SX3 so Reed thinks its closer to a 1.20. In my opinion it looks <.96. I have really good spool data to compare to but I will be changing multiple things like the primary tube sizes so I'll only see an overall change.Nice! What's the A/R on your new housing? Please keep us posted on spool-up differences vs. your existing set-up.