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90 degree fittings

Discussion in 'Watercooling' started by alexkyriak, 24 Aug 2021.

  1. alexkyriak

    Gangster

    Joined: 8 Jan 2011

    Posts: 253

    Location: London, UK

    I have seen several comments where people state a 90 degree fitting is very bad for the flow in a water loop, and that these should be minimised as far as is possible. Is this actually a concern?

    my next loop is almost definitely going to be soft tube. But, all rigid tube design are mostly based around 90 degree turns.

    So, what’s the consensus? 90 degrees = bad? Or not an issue? Thanks :)
     
  2. HoneyBadger

    Mobster

    Joined: 2 Aug 2016

    Posts: 4,034

    Location: Third Earth

    Not an issue.
     
  3. Radox-0

    Mobster

    Joined: 9 Mar 2015

    Posts: 4,184

    Location: Earth

    You can impact flow rate, but most pumps I have found flow with the solid pumps to be a non-issue in reality.

    My main build has 19 x 90 degree fittings and is fine, not great but also has loads of blocks in it which are restrictive. My HTPC build has 14 x 90 degree fittings with a single DDC pump and is also fine.

    So yes, there will be a slight impact to flow rates and seen it when I replaced a couple of the 90 degree fittings while setting a temp loop up and looking at flow rate, but not to the point its an issue. I expect most will use far less fittings then I do in general, so be less of an issue.
     
  4. alexkyriak

    Gangster

    Joined: 8 Jan 2011

    Posts: 253

    Location: London, UK

    OK thanks a lot guys, suspected as much.

    19 x 90 degs fittings? Jeepers! Sounds like an interesting build!
     
  5. LePhuronn

    Soldato

    Joined: 26 Sep 2010

    Posts: 6,591

    Location: Stoke-on-Trent

    What's more restrictive? A 90 degree adapter with a continuous 10mm bore, or a GPU terminal block that routes 11.8mm diameter holes into 14x3mm slots?

    The way radiators and blocks are designed are arguably more restrictive than any angled fitting adapter, and if your pumps can push through blocks and rads fine, in the real world those angled adapters aren't going to cause any issues.
     
  6. MikeTimbers

    Sgarrista

    Joined: 18 Oct 2002

    Posts: 7,878

    Location: New Eltham, London

    All restriction is bad, m'kay? But the world has moved since it as really anything to worry about. When the best pumps we had were pond pumps and flow and pressure were severely limited, it made sense to have as smooth a tubing run as possible. But now with DDC and D5 pumps it's really not an issue.

    I'm old school so I still try to minimise restriction but I don't try to eradicate it :)
     
  7. Drumroll

    Wise Guy

    Joined: 5 Mar 2017

    Posts: 1,667

    Location: Cambridge

    The only scenario where I was able to notice any measurable drop in flow was when using a 90 straight at the output of the pump.
    But that would depend on your entire (unique) loop.
    I wouldn't worry,
    Rads and blocks adds much more restriction than angled fittings ever will.
    Yes, you'll notice some drop in flow but most of the time, unless using a wimpy pump, the pump at 50% + would be more than enough.
     
  8. clone

    Soldato

    Joined: 11 Jul 2003

    Posts: 6,690

    Location: Telford//west mids

    Buy the ek torque 90 as there is no movement from side to side like the rest suffer from I've just replaced mine thay are 100% better.
     
  9. LePhuronn

    Soldato

    Joined: 26 Sep 2010

    Posts: 6,591

    Location: Stoke-on-Trent

    Zero play in the Barrow fittings I have. In fact, I'd argue they're a little too tight as they're a pig to actually rotate.
     
  10. clone

    Soldato

    Joined: 11 Jul 2003

    Posts: 6,690

    Location: Telford//west mids

    I have 2 barrow 90s and they both have play in them.
     
  11. LePhuronn

    Soldato

    Joined: 26 Sep 2010

    Posts: 6,591

    Location: Stoke-on-Trent

    Manufacturing tolerances I guess, although there is a difference between Barrow and Barrowch fittings. None of my Barrow adapters have any play, but the Barrowch push fittings I have have a measurable tolerance in them.

    But still nothing leaks.
     
  12. Jay85

    Sgarrista

    Joined: 22 May 2010

    Posts: 7,715

    I have a few in mine and makes little difference, any turns or bends will do the same but its not that noticeable unless its really excessive.
     
  13. SirConfused

    Hitman

    Joined: 3 Feb 2009

    Posts: 683

    I'm at 5 90's and 2x 45's with 2 of the 90's being linked. While I noticed a difference from my last loop that only had 2 90's in it, there's absolutely no flow issue from my 10 y/o D5. As others have said, unless you're using a goldfish bowl pump you'll be fine :D
     
  14. Cadder

    Wise Guy

    Joined: 25 Nov 2020

    Posts: 1,263

    Tight bends in fluid systems increase turbulence. The angle itself isn't too bad as you can have a tight 90 degree bend and a smooth 90 degree bend.

    PC cooling is fairly low pressure so it may not be as big an issue. In industrial hydraulic design with high pressure systems we would make changes in direction as smooth as possible.
     
  15. Hakanese

    Wise Guy

    Joined: 20 Jun 2013

    Posts: 1,829

    I wouldn't stress the 90 degree fittings, I'm running 4 QQDs, 7 90's, 6 45's all through gpu, cpu, and backplate cooling blocks and 3 480 rads 2 of which are external all on a single D5.
    As long as you have a decent pump your flow will be more then adequate.
    I'm also running a mix of Barrow and Alphacool. No issues with either.
    If you're going soft tubing you have the option to drop angled fitting later and just make a longer curved run if it bothers you that much, but even at 120lph my loop is perfectly fine at dispersing 700W of heat.
    Don't worry about the fearmongering, alot of info out there is based as others in the thread have said on old information when using aquarium pumps was a main way of powering a loop. Modern pumps these days are probably overpowered in most cases.
    So build your loops with fittings to make the runs that you want. If there's any issues, the forum will be here to help out
     
  16. alexkyriak

    Gangster

    Joined: 8 Jan 2011

    Posts: 253

    Location: London, UK

    Thanks alot guys. The main reason I had asked this question initially was that I posted a build on here in 2015, and got a comment or two about the number of 90 degree turns (despite the number of quick disconnects I had on that build!). I thought it was a little bit harsh at the time, but it was the first computer I had ever built so didn't really know how "wrong" I'd done it (or not). It worked very well though. Here

    Am about to do my second pc build as you may have seen in other posts. The first system has dual D5 pumps, whereas the new system will likely be a single D5, driving 3x360 rads.

    So in planning the loop design for the next system, I wasn't necessarily worried about using 90 degrees, but wanted to cover off the question with those far more knowledgable than I - ie, you lot! :)

    Another associated query would be about pipe run length; am almost certain to use some "through" radiators, partly to shorten the pipe run. From what I've read, it should be a consideration for this new build.
     
    Last edited: 27 Aug 2021
  17. SonicSW20

    Wise Guy

    Joined: 1 Apr 2019

    Posts: 1,294

    Depending on how tight the radius of the bend is (or worst case no bend at all, just a 90 degree corner) flow will disconnect from the inner edge and effectively reduce the diameter of the pipe at that point. This concept is where the "90 degree bends = bad" comes from. In practice there are multiple variables - radius of the bend, flow rate etc that will affect how much this comes into play if at all.

    In practice unless your pump is pretty marginal it likely won't matter.
     
  18. Hakanese

    Wise Guy

    Joined: 20 Jun 2013

    Posts: 1,829

    Unless you're running a lot of tubing, Run length is up to you, be it for looks, I plumbed in a spare res and pump as I added 4m of tubing to my loop so I could move my radiators out the way. Crossflwo radiators are nice as they can tidy up runs and keep tubing from blocking access to other parts of the pc. I will always remember a friend who had to drain his loop whenever he wanted to change memory, or plug new fans in.
    Don't get too hung up on what people think of your loop, as long as it keeps the parts cool, and doesn't leak, and you like the look of it, I would say job well done. I will say one thing, fan hub will save you time and effort with controlling the fans on your radiators, and plugging them in and out, especially if you have hardtubing going across the face of your motherboard