An outlet housing for an aircraft cabin air compressor includes a volute comprising radially inner and outer portions, and having first, second, third, and fourth circumferential regions. The first circumferential region is between the fourth and second circumferential region. The second circumferential region is between the first circumferential region and the third circumferential region. The third circumferential region is between the second circumferential region and the fourth circumferential region. A portion of the volute in the first circumferential region has a first wall thickness. A portion of the volute in the second circumferential region has a second wall thickness. A portion of the volute in the third circumferential region has a third wall thickness. A portion of the volute in the fourth circumferential region has a fourth wall thickness.