Custom Fab Recirculating Downpipe Question
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This is a discussion on Custom Fab Recirculating Downpipe Question within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; I am going to my fabrication guy tomorrow because I have grown somewhat tired of the sound from my 44mm ...

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    Custom Fab Recirculating Downpipe Question

    I am going to my fabrication guy tomorrow because I have grown somewhat tired of the sound from my 44mm wastegate and dump tube. I will be converting to a recirculating down pipe. My question is if anyone has recommendations as to how and where the piping should be welded. I am confident in my fabricators work, however I always find it helpful to have suggestions from those who have had experience with the same work. I have done some searching on various forums and I've found that it seems the tubing should come in around 18" back from the turbo but what I could not find is where exactly on the down pipe it should be welded in. I can imagine that if done incorrectly it could disrupt the flow of exhaust gases. If anyone has any pictures or advice on the situation I would greatly appreciate it.

    Thanks

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    zax
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    Moderator Donkey's Avatar
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    The angle it comes in at as well will make a difference. I would say you would want it 30 or less. But honestly an easier way to deal with it is just weld on a "mini" muffler to the EWG dump tube.
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    Perhaps I'll go the mini-muffler route, seems to be a less complicated solution

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    Quote Originally Posted by thump88 View Post
    Perhaps I'll go the mini-muffler route, seems to be a less complicated solution

    Supertrapp

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    Quote Originally Posted by MainFrame View Post
    Supertrapp
    Yup...
    Last edited by Donkey; 01-09-2015 at 01:18 PM.
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    Muffler seems ideal. I'm going to order one over the weekend. Once I have it set up, I'll post a before/after video. Thanks for all the help and comments.

    Stay tuned...

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    Mmmm invidia ewg muffler? Lol. Would sound sick
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    Installed my Supertrapp yesterday, amazing customer service from Summit Racing, received the product the next day, even with ground shipping! Chopped the muffler down a bit in size and took about two inches off the dump tube. This allowed the muffler to be flush with the lowest part of my down-pipe so there was no compromise to ground clearance. Cutting it down a bit also eliminated movement from the additional weight of the muffler.

    Review:
    I am very pleased with the results, it is significantly quieter than before. Of course, the waste-gate is still audible, but it no longer sounds like the finale of a Hell's Angels Bike meet. I left all 12-discs in for now, down the line I may toy with adding or removing some to examine the difference in sound. For now, I'll just leave it the way it is. I have attached a few pictures and a "Before & After" video. I truly believe the video does not do the muffler justice, but it gives you an idea. I also run a Perrin exhaust which is so quiet that anything can be heard over it.

    Thanks for all the suggestions and help!!!

    Click image for larger version. 

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    Click image for larger version. 

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    Saw your post on So Cal Subies, but video wouldn't work. It works on here. It sounds really good.

    Having it open like that, do you get fumes inside?
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    By the time the wastegate is open, the car is accelerating fast enough that the fumes would be wicked away from the car quite easily
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    Nope, never had any issues with fumes inside the cabin!

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    Thanks for the sound clips.. I've been considering adding a muffler to my EWG for a while.


    Sounds like it knocked the volume down quite a bit, without changing the tone too much.. perhaps a little less raspy, but that's about it.

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    Quote Originally Posted by MainFrame View Post
    Thanks for the sound clips.. I've been considering adding a muffler to my EWG for a while.


    Sounds like it knocked the volume down quite a bit, without changing the tone too much.. perhaps a little less raspy, but that's about it.

    What I really noticed is the muffler took the throaty, kind of thudding note out of it. You can still hear the "rattlesnake shake" but it is significantly quieter.


    I would assume with a slightly louder exhaust (louder than the one I have), the dump would be almost inaudible.

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