I am running a new washer box. The original one had the water and drain on the wall. Since I have gutted the bathroom, I could install a new box, larger supply pipes, and proper 2 inch drain because that is the backside to the laundry area. When I drilled the hole for the drain line that goes into the crawl, the block wall is preventing me from having the p-trap directly below the drain. I am needing to run an elbow to get the drain out past the block wall and then run the p-trap. So, i will run the 2 inch PVC drain down about 3 feet and then put in an elbow, run about a 10 inch section of pipe and then the p-trap. So, can I run a 90 before the p-trap?