does tubing size matter?

I currently am running 1/2" ID tubing through most of my system, with one section of 5/8" ID tubing from the outlet of the rad to the inlet of my mag2. Darn redesign where they removed the threaded connection Anyway... I am in the throws of designing a new system using a reservoir where the pump will be submerged.

For reasons of usability, I was thinking of dropping my tubing size to 3/8" ID. I would have to get some new connectors, but that isn't a big deal. Is this a good idea or not? It seems that everyone used to say 1/2" was the best to use, but I am not sure if that is still applicable anymore.

BTY, I am using the chevette or caprice heatercore (haven't deciced which one yet), Maze4 and either a Mag2 or Mag5 (have both). What do you think?

Take a look at the last graph. As you can see, !/2" makes a big difference.

Or perhaps some real world data.

I wouldn't go any lower then the 1/2" ID tubing. Genreally more flow is better.

I plan to use a short section of 3/8" tubing, but only in a section where flow is parallel, and the actual flow area with 2x 3/8" is a little larger than 1x 1/2".

Generally, as large as you can get within reason is the way to go. I use quite a bit of 5/8" ID in my setup.

johan851 said:

I plan to use a short section of 3/8" tubing, but only in a section where flow is parallel, and the actual flow area with 2x 3/8" is a little larger than 1x 1/2".

Generally, as large as you can get within reason is the way to go. I use quite a bit of 5/8" ID in my setup.

Click to expand...

There seem to be little data on 5/8" ID loops somehow. Or? Uberblue's graphs do list 3/4 and 1", which seem promising in this abstract representation.

IN any case it seems to me that it's fairly contra-productive to have only parts of a loop with a higher diameter, as the smaller sections will become the bottleneck. Not to criticize your particular setup- it may still help by reducing flow impendance in those areas and thus still pay off. It's just that I'm not certain about when it results in tangible benefits.

well the one section of 5/8 was out of necessity, not out of design. my new setup will use all 1/2" ID tubing since that particular loop of tubing is going to get replaced by the res. Thanks for the inputs and for confirming that I am still doing the right thing