I was wondering if anyone with a stock turbo ever made their own dump tube so the wastegate has a smoother flow. I'm thinking about making one because I have plans to buy a bnr stage 4. I just reread my post. Maybe I should have called it a "bell mouthed downpipe". I just see the wastegate opening to the plate. I wouldn't mind smooth flow

 

i have seen people do it but it only helps aid in better boost control, you will also need to build a divider between the turbo outlet and the wastegate area.

when most people go to such lengths they eliminate the internal gate, open the ports much more and use an external gate plumbed through the stock turbo backplate. question is, do you really need it? i hate screamer pipes, and in many cases it keeps you from running certain tracks and brings unwanted attention to you in other areas.

 

I wasn't planning on dividing it. I just wanted a smoother flow for the wastegate to exit. It is a bit of trouble. Sorry my wording was bad. I think "bell mouthed design" would be a better description.

With these big hybrid turbos on the s5 turbo, and with the only wastegate option being porting it out, I'm a little worried. Even though the s4 turbo manifold and design is horrible, at least People are able to make it bigger and put a bigger wastegate valve on it.

 

without a divider you will have exhaust bypassing the main exhaust system and going out the wastegate dump pipe all the time.

 

Yeah, I'm just trying to give the wastegate a little more area instead of hitting the plate that comes stock, then merging with the downpipe which has a 2.5" hole in the flange.

Just like this one
Google Image Result for http://www.speed-element.com/catalog/02-07-subaru-impreza-wrx-sti-bell-mouth-wide-band-bellmouth-down-pipe-1.jpg

Better than the stock plate, no? Sorry, my title was wrong.