Size to port wastegate on CT-9

sMARTINside

sMARTINside

Member +
Hi, I am about to port the wastegate of my CT9b and I would like toi know what is the best size to go to. I measured it this morning and it as 22 mm stock. I will machine it on a vertical axe milling machine at work and the only bigger size of endmill that I have available is 1 inch. That is 25.4 mm. Would this be too big? I have read before that going to 24 mm is good. By the way, the gate already has 2 thin cracks on each side.
 
sMARTINside

sMARTINside

Member +
I know that the more I machine it, the more I run chances to crack it more. I forgot to say that I will run this:

-Stock actuator
-FMIC
-Uprated exhaust manifold: SPS mild steel ceramic coated
-5E-FHE ACIS variable intake manifold

I think I should have very good Intake/Exhaust flow with these mods, which makes me think that I should open the wastegate I little more. Am I right?
 
Dub-Se7en

Dub-Se7en

Lifer
mine was bored out 2mm to around 24mm, not been able to test it fully as i'm still running in but seems to hold boost much better than before, it spiked quite badly the other night, but the weather was freezing cold so i'm putting it down to that.
 
sMARTINside

sMARTINside

Member +
How did you guys get the wastegate door out to have enough space to machine (the wastegate is in the way). I think the only way is to cut the welding that holds the shaft to the actuator lever. Then, the shaft should come out? I need to know your experience before I find out the hard way. At least I have a spare CT9a at home that is my guinea pig!
 
Dub-Se7en

Dub-Se7en

Lifer
the flap will hinge right out of the way with the actuator disconnected.

edit: it is also better to remove the turbo to do this.
 
sMARTINside

sMARTINside

Member +
For sure the turbo is already out of the engine. I have a CT-9A turbine housing right now beside me and the wastegate isn't opening enough to clear the space needed for my tool to pass.

I just took a pic to prove that:

P2263477.jpg
 
sMARTINside

sMARTINside

Member +
Ok, I see now! Your tool was not coming directly strait in the hole, like if I would use a milling machine. Our turbos are the same after all. It, just that your tool was not the same diameter all the length. Thanks for the pics! Maybe I'll try it this way, with a die grinder.
 
T

Toby@ToyTuning.com

Banned - DO NOT BUY FROM TOYTUNING
In essence the more air you have coming into the turbo the more you need to exhaust, the stock w/gate is pretty small so you can get boost creep issues with the stock size, this just aids the process :)

Thanks,

T
 
dac69er

dac69er

Super Moderator
you cant do this very well on a milling machine unless you have specialist tools or you can remove the wastegate flap.

die grinder is the easiest way. you have to be careful too as the wastegate flap doesnt sit perfectly central on the hole, plus it also has some movement in it. you have to take this into consideration so tou dont take too much off one side of it and cuase it to not seal.

i did mine in situ on the car, risky, but it worked ok.
 
Bullet00th

Bullet00th

Member +
I'm going to be doing mine next weekend. If stock diameter is 22mm will 24mm be enough, as i do suffer majorly with boost creep!!! Or should i try to take alittle more aslong as the wastegate flap still seals ?

Any advice would be brilliant because i have never done anything like this before :D
 
sMARTINside

sMARTINside

Member +
I made a test on my test turbo, 3 weeks ago, and 1 inch (25.4 mm) is too big. I drilled it on the milling. Had to remove the lever, and the slid the wastegate out. I used a 1 inch drill. The problem is that the wastegate's door gets to hook in the hole and get caught there sometimes, so if I installed this turbo, sometimes it would boost and some other times, not. Was worth the test. So on my actual turbo, I will go for a 15/16 drill (24 mm).
 
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