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Discussion Starter · #21 ·
I honestly dont think I will see much if any loss, but I would like to prove it or prove its at least minimal for my setup. I didnt notice any change in the butt dyno but we all know thats not an accurate measurement. I have a 3.5 inch downpipe split into a Y pipe with dual 2.5 exhaust and straight thru mufflers. Im willing to lose a little power on the street for no wastegate noise. I dont have any boost creep issues even at wastegate pressure which is only 6psi.
 

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I run an external gate plumbed back into the exhaust on my other car (not a mustang). I built the down pipe with the waste gate tubing joining in the general direction the exhaust is flowing. No issues.
 
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I’d be surprised if it effected power in any way if you merged the wastegate outlet. Your car must be pretty quiet to notice the wastegate sound over the turbo and engine.
 
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Discussion Starter · #25 ·
Its not that quiet. Its normal for a full exhaust turbo v8. If I bypass the turbo, the car is loud, too loud for me, way louder than 40 series mufflers. Just about every turbo car ive built, 4, 6 or 8 cyl with vent to atmosphere, the wastegate opening is noticeable. 20 years ago me and my friend turbod his Subaru RS with a 2.5. This was before WRX's came to the US. The wastegate dumped directly under the car and people racing us would literally pull up after the race and ask what the loud noise was when the wastegate opened. It was so loud it would scare people. When I do the dump vs plumbed test, IM going to take videos.. This isnt a slight change. I really think it has more to do with the amount of exhaust bypassed vs going through the turbo.
 
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I used this for a little while on my wastegate to muffle the sound and it worked pretty good.
Door Wood Automotive tire Plumbing Gas

I couldn't justify spending the money on getting the wastegate plumbed all the way to my downpipe but that's just me.
 

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Discussion Starter · #27 ·
That thing looks like it's about to eat something 😂. I have my own tig welder so it only cost me time, a little piping and a flex joint. It was a PITA to get it plumbed in but it was worth it to me.
 
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I run a wastegate muffler, huge difference in sound between open dump and run thru a muffler or into the downpipe for me.

I doubt any difference in power whichever route you choose.

My only concern would be ability to control boost creep especially if your exhaust has high back pressure already. You may or may not have that issue.
 
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@stangjumper what is your power level, how much boost do you run and what size turbo(s)
Power level depends on boost. Precision 6466s. I run 4.5- to upper 20s psi, so far. Power 500+rwhp to 1100rwhp, for now. Dyno session got cut short. Haven't gone back yet.

I hate the open wg sound also. I made custom mufflers for mine. That was my comment of you not wanting to do what needs to be done (wg mufflers). Mine can not be heard at all.

There is no doubt in my mind that the wg being piped back into the dp cost hp and spool time. The more hp you are running (exhaust flow), the more it is costing you.

I have twin 3" dp's the whole way to 3" tailpipes. I also have cutouts under the car that open under pressure (with custom mufflers on them, can hardly hear them open). I can tell you at 7psi, it cost me 20rwhp keeping the cutouts closed. I'm sure it is 100+hp at higher boost levels. I didn't have time to test yet.

Bottom line, you want as much exhaust flow as you can get, period. At least that's why I spent all the money I did, to get the most out of the combo. Route the wg gasses away from the exhaust system.

I know on my old gts76 combo, a 3 1/2" dp was worth 50rwhp over a 3". Open dp was worth considerably more with quicker spool time.
 
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