Dodgy internal or expensive external? CT20b on ST165

[sergei]

Hi, Currently in process fitting CT20b to my ST165, obviously people who have done it know that there is clearance issue between wastegate and factory oil cooler supply banjo bolt. So to fix that I had to grind the bolt and bend sligtly wastegate pivot to make clearance of about 2-3mm. Now 2-3mm between moving part, heat expansion and bent/slightly relocated wastegate actuator is somewhat dodgy (in my opinion). So I'm thinking of external wastegate, the problem is that I'm using stock manifold and there is not enough room to fit the wastegate (due to intercooler). The other way is to remove stock wastegate weld a plate shaped as semi-circle (or maybe a pipe) to aftermarket down pipe (so it will isolate wastegate flow from turbine flow) and weld the wastegate mounting pipe to downpipe. Any suggestions in that regard? I think the biggest problem in that design would be creating seal between down pipe and wastegate area on the turbine...
Here is the pic:

[slighty_sykotic]

Thats not going to work??

If you mean the downpipe, as in the pipe after the turbo...

The wastegate has to vent gas from BEFORE the turbo. Otherwise all you a doing is making noise...and free boosting.

--Sykotic

[sergei]

It will be venting before turbo (i'm not stupid), the problem maybe in isolating wastegate gases from gases exiting the turbo (and viceversa).

[wde_bdy]

The effect on flow through the turbo by basically spacing the wastegate away from the turbo housing would be pretty bad. I can see it giving very inconsistent boost control and slow response. You either have to accept the current limited clearances or do it properly with a new manifold or possible different turbo.

Callum

[sergei]

different turbo is out of the question, especially when I paid over $1500 for it.
The turbo to manifold gasket turned out to be much fatter then I expected, so I have a bit more of the clearance now....

[MrDori]

jUST GET AN EXTERNAL