I have gathered all the materials to start tacking together a manifold for my Evo 3 for use with a stock Evo X turbo. Got the head flange from RRE and the weld els from acestainless. It will be a short/unequal/oem runner setup to keep the lag down and response good (I do not have mivec and am going from 7cm to 12cm so every little helps)

Seeing as my turbo did not come with an actuator, and I wanted to go external anyway I will be using a single Tial 44mm wastegate to keep weight, cost and complexity down.

Option 1
Fab a divided merge "collector" from each of the 2 merges on the turbine inlet collectors with the divider wall ending up ~1mm away from the valve face in the Tial.


Option 2
Mount the wastegate on the O2 housing like the ATP downpipe for the Evo X.



Option 1 will take a little more time which I am not too concerned with but being honest I am an amateur welder but even though I have an excellent teacher the less odd angles to cut, the less things there are for me to worry about messing up. Trying to keep it as simple as possible

Option 2 has me a little confused. If i cut away the stock flapper the divided volutes now share a common chamber which in my mind would defeat the purpose of the twin scroll design. Would I then need to fab a short divided tube that almost butts up against the divided opening where the flapper was and bring the divider up to the valve face again? I realize that the stock acutator flap is not air tight against the turbine housing when it is closed but two sides are far less likely to mix compared to having the small shared chamber

I was advised that since there is no real flow in that relatively small chamber until the waste gate opens that there would be no measurable loss in transient response.

If i would have to do the small divider to reap the full benefit in option 2 then i may as well take it off the manifold.

 

You still had the evo nix? what happened to the tezza?

1 it is

 

Keep the divider all the way to the gate. You can safely get it about 1/16" away, but too close can make it hit with heat. The divider is always hotter than the outside of the tube so it expands more.

Kevin

 

don't waste your time with the ATP unit as it will act exactly as you presume it to and will turn your nice twin scroll turbo into a single scroll.

 

I did option 1 and it works well. I know this because I had no divider wall to speak off before (test) up to the Tial valve before and it made a 250 rpm spool-up difference after I had the wall extended all the way to about 1 mm from the Tial valve (concave surface btw)!