question about wastegate and turbo combo

[GreddySpyder]

From what I've read, the wastegate piping is part of the o2 housing. I plan on getting an aftermarket o2 housing, but i noticed some have a wastegate pipe that loops back into the exhaust (which is an internal wastegate i assume), and some have a pipe that just sticks straight out(assuming that would be the external wastegate). I plan on getting a T28 killer turbo, would there be any advantage to getting an o2 housing with the external pipe over the internal, or would this even work properly. Somebody please enlighten me...

 

[Faded]

An external wastegate can be routed either back into the exhaust or dumped out. Heres a pic of various O2 housings.

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The T28 turbo most likely has an internal wastegate or actuator. I believe you may see better flow and performance with a dump tube on the internal. I'm sure someone will chime in and confirm or deny.

 

[GreddySpyder]

I'm assuming the ones with "dump tubes" are the 3rd one over on the top row and the 3rd over on the bottom row. With the dump tube do you have to weld a longer pipe onto it to give it a safe place to "dump". As short as those pipes look it seems like it would be dumping under the hood, that just can't be good. I saw in SCC magazine that jon huh has his dump tube coming out of a hole in the front bumper, and that it has a tendency to shoot flames, definitely not good under the hood, any suggestions as to what is best? Correct me if i'm wrong on any of this, i'm still new to the world of forced induction.

 

[Faded]

You are correct those are the dump tubes. Honestly I don't think it will matter on length. You are dumping exhaust straight down below the engine bay. I imagine if you wanted to you could extend them but there may not be a purpose to it. Typically they design the O2 housings with enough pipe so that it can dump out and not be too long to hit the ground. BTW - some dump tubes are loud enough to scare women and children from blocks away. It depends on your setup but they sound loud and mean as hell. I went with the stealth mode - routed back into the exhaust. I can't afford a 'fix-it' ticket from hell. I don't want to draw any unnecessary attention

 

[GreddySpyder]

Originally posted by Faded
BTW - some dump tubes are loud enough to scare women and children from blocks away.

Thanks for that, I've had a long day and needed a good laugh!

Although that is another thought, I don't want a really loud exhaust system, I'm loving the relatively low volume and tone of my Greddy EVO exhaust.

 

[larryd]

if you prefer a relatively low volume system do NOT get a dump tube.. its that loud.. take my word for it

 

[GreddySpyder]

Originally posted by larryd
if you prefer a relatively low volume system do NOT get a dump tube.. its that loud.. take my word for it

Thanks for the advice, I've been wondering how much louder it is going to get with a 3" downpipe and cat, which i definitely want to do... but i guess i may be skipping the dump tube idea after all. What all does the dump tube do for you that routing back into the exhaust wouldn't?