hmmm my casting there is a long smooth transition angle not 90° for certain!
i will get a pic up at a better angle.
maybe this has summat to do with racer's post that this casting is bespoke and has had some restrictions corrected?
.
going out for 1hour

 

sparky,
You are talking about porting the area of the wastegate hole? Why? Is he having boost creep issues? That porting does not affect the twin scroll at all. Does it? Whats the main advantage of doing that? I am just trying to understand the reasoning behind this.

 

My bad, racer. I just assumed that he was wanting to improve wastegate flow after reading his post #4 earlier in this thread. However, the axiom that if it ain´t broke don´t fix it may apply in this case. I just jumped to the conclusion that he wanted to avoid boost creep, although the OP never expressly mentioned it.

Part of the problem is that whenever I port a gated housing, the first thing I do is open the radius to the bypass ports. It´s just an old habit of mine left over from my days of running Garrett T04E turbos on my Buick Grand National. But, that´s another story.

Lee if your particular housing has a fairly open radius at the entrance to the bypass port, then just leave it as is. Since you´ll be going from a 9.8 cm housing to the looser 10.5 there will be even less propensity for the turbo to creep anyway. Like I said, I just do the WG port blending on all my exhaust housings out of habit. Old habits die hard.

 

lee, there is something else to port in the pic in post #45. This time it is on the other volute though. Let me know if you want to continue or not.

 

 

First let's concetrate on area above the curved yellow line. It's easier for me to visualize it if you were to rotate the image 180*, so that what is now the top of the picture would be at the bottom.

Are you at all familiar with firearms? Would you happen to know what a ramped barrel on a Model 1911 Colt .45 automatic pistol refers to? Anyway, that area above the yellow line is an abrupt wall which interferes with smooth exhaust flow.

Gotta Go now.

 

Ok so you guys got a little ahead of me in the last few days and Im a bit too lazy to read everything, not to mention you guys started using some real big words.

Now I admit, I dont get all scientific like some of you guys here. I primarily work off theory, advice and trial and error. I have been porting anything and everything I can in my garage for friends and myself for the past several years. With the hotside I started looking into it after a few posts from 9sec9 and seeing the results of some of the stuff he had ported for some of the buscher guys. Turns out that theres a whole lot more gains there then I had expected. I believe that most of the gains come from inside the collector area. The turbine area is pretty simple.

Imagine that the hole is a clock, and the turbine is the clock hands... The turbine rotates clockwise and in relation to how the exhaust exits its all between about 3:00 and 8:00 oclock. When I remove material I do so in the direction that the exhaust exits and just blend everything into it.


On the wastegate holes, I leave those alone for the most part unless theres some dead air spots there and Ill smooth out the transitions there.

Here is a graph from a VIII I did testing on, the car had minimal mods, with my ported hotside, intake and a milspec TB.... Stock fmic, stock ic pipes and stock cams, with a full 3"TBE...






Heres a red I did when they were first released.



Some pics of a green I did.










My intake

 

Heres a couple I found from the collector area..

 

Thank you for sharing those pictures of your work with all of us, Steve. Beautiful ****.

 

nice one steve
so you do blend that step away from the exduser exit?
but do it in such a manner that you only blend it a few mm into the machined profile of the turbine wheel

 

Yeah, you just have to make sure the the farthest point back stays the same size. I usually take down some base numbers as well as mark it up with a sharpie so I know where I'm working and so I don't remove material from somewhere unwanted.

 

Did you start/finish your port job?

 

i'd love to see more of this guys,
i'm getting ready to do the same on mine.
i unfortunately tried to remove the studs from the hotside/ ex. manifold mounting and stripped one! that's for another thread though.

good info guys, thanks

 

Stripping the studs can be a blesssing in disguise. Pull both studs out and use four through bolts instead. This is a definite advantage as you don't need to yank the manifold whenever you want to swap out the hotside.

 

this has been very helpful. A quick question on the long shanked carbide burrs once you attact that 90d bend in the hot side what do you get down there to smooth it out some more. Or do you just use the burr????