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  1. #1
    Senior Member Three Rings Arsenal2012's Avatar
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    Im not an engineer im a mathematician. What do you think about this exhaust crossover

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    Its a mixture of an H pipe and an X pipe.
    How do you feel about it?
    Will I get a mixture of both the low end and high end?

    The drawing is on the right, dont mind the other stuff.




  2. #2
    Senior Member Three Rings Arsenal2012's Avatar
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    I guess im just not sure if i would be better off doing the top two tubes straight at 0*-180* or angled at 1*-179* and the bottom tubing at a straight 180*-360* or angled at 181*-359*.

    Or even if...

    I should have a portion of the top tubing inserted into the main tubing to collect some of the exhaust flow.
    I will post diagrams or images of what I am reffering to in a few hours.

  3. #3
    Senior Member Three Rings Arsenal2012's Avatar
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    Quote Originally Posted by Arsenal2012 View Post
    I guess im just not sure if i would be better off doing the top two tubes straight at 0*-180* or angled at 1*-179* and the bottom tubing at a straight 180*-360* or angled at 181*-359*.

    Or even if...

    I should have a portion of the top tubing inserted into the main tubing to collect some of the exhaust flow.
    I will post diagrams or images of what I am reffering to in a few hours.


    So here are the ideas I mentioned in my last post that I am kicking around in my head and apparently by myself on this forum



    Last edited by Arsenal2012; 09-10-2015 at 04:06 PM.

  4. #4
    Veteran Member Four Rings aluthman's Avatar
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    Why not just a normal x-pipe?
    -Adam

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  5. #5
    Senior Member Three Rings Arsenal2012's Avatar
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    Quote Originally Posted by aluthman View Post
    Why not just a normal x-pipe?
    Well why not a Ford or Chevy?
    Why not follow a man named Hitler or Christ?
    Why not tread the same path?

    Why, because im looking for a balance as stated above in my original post.
    Just because you have black and white paint does not mean you cant mix them and make grey?

    I have been having the idea of building a couple designs with pvc and water testing them for flow. I just have not had the time yet to do so.

  6. #6
    Senior Member Three Rings Der Typ's Avatar
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    Quote Originally Posted by Arsenal2012 View Post
    Well why not a Ford or Chevy?
    Why not follow a man named Hitler or Christ?
    Why not tread the same path?

    Why, because im looking for a balance as stated above in my original post.
    Just because you have black and white paint does not mean you cant mix them and make grey?

    I have been having the idea of building a couple designs with pvc and water testing them for flow. I just have not had the time yet to do so.
    Calm down, aluthman only asked a question. No need to get all defensive.

    I like the idea, that you want to try something new, but I don't think that you will see any gains. The x-pipe is already superior to the h-pipe and gives you the low-end gains.
    But you could actually give a call to an exhaust shop or two and see what they think.
    I know that JHM was experimenting with exhaust systems, but could get better results than the Fast Intention ones, so they stuck with it. Maybe talk to them and see what their finding were in that field.

    If you get some results on the water flow tests, let us know.

    Good luck!

  7. #7
    Established Member Two Rings
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    Lol waste of time
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  8. #8
    Senior Member Three Rings Arsenal2012's Avatar
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    Quote Originally Posted by R y an View Post
    Lol waste of time
    Your post is a waste of time.
    Me replying to this is a waste of time.

    You offer no elaboration to your comment, have you ever had an original thought?

    Am I speaking to the inventor of fluid dynamics, did you graduate from MIT with an engineering degree and you actually know what you're talking about?

    SMH your comment is as pathetic as your breaths of air ya troll.

    Back to the topic, please comment if you have any real insight, I would love to hear!

  9. #9
    Active Member Two Rings Oblivia's Avatar
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    I like your idea of experimenting. You can learn some from using fluid flow, but remember the dynamics will be much different for air (a compressible fluid) vs water (essentially a non-compressible fluid). What would be neat would be to mod the main exhaust lines with flanged "stubs", two each. Then you could make several simple bolt-up test rigs to install and check the performance. Compressible fluid flow in a closed piping system (open at the far end) is not easy to simulate, especially since the input (motor) is affected by the flow. Wave propagation, harmonics, resonance, etc. are difficult (but not impossible) to predict in an exhaust system, even with a good CFD (computational fluid dynamics) program. Also, other variables you might want to consider in your testing would be cross-pipe diameter, cross-pipe lengths, and shape of the Y's at/near the junctions. All will likely have an influence on the outcome. I'm interested to see if you have made any progress on your testing. Best of luck!
    How fast is fast?

  10. #10
    Veteran Member Four Rings GrapeBandit's Avatar
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    Quote Originally Posted by aluthman View Post
    Why not just a normal x-pipe?
    bcuz reinvent the wheel.

    not sure what OP is trying to do, but it looks more like bridge support beams instead of exhaust pipes lol. maybe its his new calling is in architecture
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    PCV? Just dump it on the ground!

  11. #11
    Senior Member Two Rings mufflerman's Avatar
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    We have a lot of customers with ideas that are similar and have paid us to try things like this. My input is that if there are gains to be had they are nominal and potentially cost prohibitive. My advice would be to just go the tried and true X-pipe, it works very well and has a proven track record.

  12. #12
    Active Member Two Rings
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    I'm not a engineer but I play one on TV


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  13. #13
    Veteran Member Four Rings aluthman's Avatar
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    It all looks like an X-pipe that was purposely made worse.
    -Adam

    '07 DTM A4 2.0T|6MT|EFR 7163 Twin Scroll|DoTuning|Built Motor|Meth and other go fast stuff…
    '06 A4 2.0T Quattro - RIP (Best ¼ mile pass 13.634 @ 103.30)

  14. #14
    Active Member Two Rings Miami4me's Avatar
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    I'm neither an engineer nor a mathematician. As a lawyer, the closest I come to exhaust problems is when someone dies from carbon monoxide exposure. I like the idea of pushing the envelope, though. My comment is that most of the designs seem to increase the volume between the main pipes. As such, I would think they would lower the exhaust pressure. I'm not sure what effect that would have. My understanding is that H pipes equalize standing waves, though that could just be Milltek marketing. I have a Milltek catback setup on order, so I hope to have more firsthand knowledge soon. I had Fabspeed X pipe cats on my prior Porsche 997S, and absolutely loved the performance and sound.

    I'd be curious to know what effect the increase in intrapipe volume has. Keep the ideas coming. There's no substitute for empirical knowledge, so don't be afraid to experiment. Mathematics, I'm told, is theoretical physics.

  15. #15
    Senior Member Three Rings S5boxster's Avatar
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    I messed around b8s5 exhaust and other car exhaust. The diagram looks great. But it work like a h pipe cuz the straight would push more exhaust gas as it's more free than the redesigned x. in normal xpipe exhaust gases cross over for a smoother flow of exhaust gas, which help reduce drone and more top end gains and a proper low end gains. H pip naturally has more low end gains but under load will work like a straight pipe and less top end gains. My thoughts on your redesign.


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  16. #16
    Senior Member Three Rings S5boxster's Avatar
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    Quote Originally Posted by S5boxster View Post
    I messed around b8s5 exhaust and other car exhaust. The diagram looks great. But it work like a h pipe cuz the straight would push more exhaust gas as it's more free than the redesigned x. in normal xpipe exhaust gases cross over for a smoother flow of exhaust gas, which help reduce drone and more top end gains and a proper low end gains. H pip naturally has more low end gains but under load will work like a straight pipe and less top end gains. My thoughts on your redesign.


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    I would do xpipe for more exotic (euro)sound
    h pipe more muscular sound on a V8 motor.


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  17. #17
    Veteran Member Four Rings dirtybrd's Avatar
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    Personally I feel it’d cause a turbulence issue and cancel out the desired affect. But I’m no engineer


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  18. #18
    Established Member Two Rings MaxPrime05's Avatar
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    I don’t want to be crucified for having an opinion like two of my fellow enthusiasts in the above forum, but it seems to me that the bigger the angle on the x-pipe helps have less restriction for high end power, but still provides low end advantages. The drawing I’m referring to is the second one on the bottom of the 6 drawing page that was shared. It SEEMS to be the best of both worlds. Again, I’m neither Mathematician nor Engineer, but as a 16 year old kid taking engineering courses and honors classes, this was a fun brain teaser.


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