Originally Posted by 4G63W8

hi guys,

the above pics are from my setup.I have fabricated an external wastegate on an hks 45mm.I now run a green but berore that i ran the standard 9.8 hotside turbo.Both turbos benefited much from the use of the external wastegate.I run the green @ 2 bar,i have no surge anywhere,the spooling is faster and it holds the boost all the way to redline which is btw at 8000rpm.I run on standard internals and i've put down on the last dyno run on a low reader 392@wheels at 1.92bar.

Fabrication is easy,but if you want to do it yourself you need to be able to weld properly.

steps:

1. remove standard manifold and turbo
2.Cut into the manifold (above,see previous pics) so as to created a hole where the ext. wastegate pipe will be welded.The manifold is twin scroll so you need to cut into the inner wall and make anothe hole so as the pipe of the wastegate can get air from all four tubes of the manifold,do not though remove the whole inner wall.
3.Fabricate a pipe that will be attached on the manifold.You need to cut the edge of the pipe that will go into the manifold in a v shape for bettet fitment
4. Weld the pipe on to the manifold from the outside but also on the inside as well so as to attach perfectly on the inner wall and on to the hole that you have made on it.
5.Use a dremel to port the inside of the manifold removing any excess welding.
6.On the turbo,remove the internal wastegate with a actuator,weld the flapper(wastegate door) shut,also weld the little handle (where the actuator connects with a pin) on the outside of the turbo.
Bolt the turbo on on the manifold and bolt the manifold on the car but not fully,as you may need to remove it,this is just to make you able to fabricate a screamer pipe.
7.Create an external wastegate screamer pipe,you can either run it into the downpipe or leave it out if you like the sound of it,mine is out and loud.
8.Bolt the manifold turbo and screamer fully on to the car.

Needless to say that you need to weld flanges of the wastegate you will use on both the ext. wastegate pipe that is attached on the manifold and on the screamer pipe.I use the tial 38mm one.

You can do the same process on the standard maniflold,you just need to port it first especially if you are going to run a green.

I hope this helps,any questions feel free to ask guys.

Originally Posted by RevMoto

I see you only have the wastegate modded to only 2 runners. In a twin scroll you need both sides plumbed.

Originally Posted by addo

Excellent reply what are the main advantages as i'm interested in this myself.


1. is it better spool?
2. does it hold the boost better
3.is there more progression on the boost control?



If this is significantly beneficial vs std flapper waste gate i think i might sell my Evo 400 modular down pipe and std turbo buy a full race and fabricate a tial on there maybe with option screamer & flange to recirculate the waste gas.

do you have any fabrication pics or pics of the manifold off the car?

cheers

Originally Posted by 4G63W8

That's where you are wrong my friend,the center pipe goes all the way down to the point where all four runners connect and gets air from all four

Originally Posted by RevMoto

but the 4 runners never meet. Only 2 meet. Having said that, having the external wastegate on the hotside such as this might work better.

Originally Posted by 4G63W8

guys please read my post carefully,they don't meet mate because there is a wall in between them,that's why it is called twin scroll and that's why you cut into the wall so as to make them meet and join all four with the fifth centered wastegate pipe.

No mate, it's not better,there is a great chance not to be able to control the boost as much as you want