Say I had a nice juicy turbo, that just so happens to be internally gated and I wanted to keep it that way for emissions reasons.

The turbo would then be installed on say, one of those XS power manifolds that have runners for an EXTERNAL wastegate. The turbo would be installed the the usual fashion, with the external 38mm opening in the runners blocked off with some steel sheeting.

Apart from the fact that the XS power manifolds suck in general, is this a faux pas?
I could see how exhaust flow might suffer a little due to the back pressure, but from my knowledge of fluid flow in pipes, the loss would not be appreciable. Any turbo junkies think something about this idea?

 

going to a bigger turbo wont affect your emissions(properly tunned car)you can get rid off the internal wastegate(weld the flapper shut) and use a external unit(people do that all the time)or get a T4 hotside(external wastegated unit)in order to use your juicy turbo,dont get me wrong buddy but it looks like you want to go one step backwards instead of moving forward,can you post the specs fo the turbo?

 

Going from no turbo, to turbo is still one step forward.

Its a Mitsu TD07-25a 13cm turbine housing... not small. It came with the JDM engine I bought.

I know what I CAN do with welding the flapper and the external wastegate and whatnot, but I don't want to do that. I'm not building a drag car and I have strict emissions to pass, so until emssions are passed, all exhaust gas stays in the pipes till it passes the cat.

My question is basically: what is welding off the wastegate runner on the XS power manifold (or HKS) going to do, if anything?

 

im not %100 sure but i guess that a TD07 does not have a T4 flange,so it will not bolt on to any of the aftermarket manifolds meaning that a custom flange is needed to make it work.Now to answer your question if i was you i will cut the wastegate runners off and weld a plate in place,why?cuase if you left the runners in place and just cap the wastegate hole the exhaust gases will run down the wastegate runners bounce at the end come back up the runners and hit the incoming exhaust gases affecting flow,i dont know how much or if it will make a difference but it will happen

 

Thats kind of what I figured. I didnt think of cutting it tho. Decent idea unless I wanted to switch over to external WG later of course.

On the bright side, it has a T4 footprint.

 

what about if you use a stock s5 manifold?i seen people making custom spacer in order to bolt a T4 aftermarket turbo to a S5 maifold plus the s5 is way better than the SS auto crap one

 

Perhaps. Ill have to source a spacer and an S5 manifold for that.
SS autocrome is quite bad, its true. Thats why i might get the HKS one instead.

 

TD07 is T4, TD06 is T3.

The problem with an internal wastegate is that it might creep. The XS power manifold is a knockoff of the HKS cast manifold which is already notorious for bad boost creep even with an external wastegate. I don't recommend an internally wastegated T4 turbo on a rotary.