Elbows and Increased Inner Diameter (ID)

I bought my setup second hand and the DIY reservoir the seller made incorporates an elbow fitting as an intake barb. After reading these boards, it's clear that elbows are bad for flowrate, but one thing intrigues me: The intake elbow has an ID of 1/2" (5/8" OD) instead of 3/8" ID (1/2" OD) like my CPU block, pump and radiator. In fact, I had to heat my 1/2" ID Tygon tubing just to slide it over the elbow barb.

Does the increased diameter help alleviate the flow restriction of the elbow? I was thinking about making another reservoir, but I'd rather not disconnect my system again.

That one elbow won't do much of anything to your flow unless you are using a pump that is less than 150gph otherwise I say don't worry about it.

It helps, yes, but the 90degree turn is what realy hurts. I got some copper tubing bent into some gradual elbows for me, and they work great.

What about a 5/8" ID elbow?