ball-bearing hybrid turbo results

[88turboii]

so i did it, i made a BB hybrid using a garrett BB chra, but did not get the results i expected. I was running a 60-1 hifi compressor with p-trim turbine wheel on stock journal bearings before. all i did is order a garrett BB 60-1 chra with p-trim wheel and swapped compressor backplate with my hifi and bolted the hifi compressor cover on. With some minor clearancing it fit pretty well. and the coolant ports were 14mm instead of 16mm, but no big deal

but.. spool seems to have gotten worse by about 500 rpm, i used to get 15 psi by 3500 rpm with the journal bearing, now it doesnt hit 15psi till after 4k! what gives? the only reason i can think of why it spools slower is the added rotating mass from the inner race on the turbine shaft.. where as journal bearing has no inner race