After leveling shower floor for new shower base, I need to raise height of 2" drain pipe about 1.75" to accommodate a "no-caulk" base drain. The pipe is buried in concrete foundation.
I found a pipe extender marketed for pool plumbing with a 1.25" L narrow end that fits inside the 2" pipe, and gives me an extra 1.25" of height.
This reduces a portion of the internal diameter of the pipe to roughly 1.75". Will that quarter inch loss be significant enough to slow drainage in a meaningful way? Once it's in and shower redone, there's no going back!