Wastegate Flap

[jonn]

hey ive just had my turbo ported and bigger flapper, and 12lb actuator installed. unsure how far the old flapper opened, wondering if the wastegate is now opening enough? only looks to be opening 75%. is this normal?

Edited 16/05/11 08:21 AM by jonn

[Ralph Wiggum]

Thats good mate, any more and you risk it over centering and jamming open,

Correction to the above comment, you actuator arm has the pin on the inside, meaning the actuator arm will foul on this before it over centres. If you have the pin on the outside and went past the point shown in your pic it could jam.

Got any better pics of the port/inside the turbine housing?

[jonn]

oh yeah awesome.

ill take some with my actual camera now

[jonn]

dont wanna take the manifold off. just some clearer shots

[Ralph Wiggum]

Its looks to be pretty good, going by the first pic the port is the correct "D" shape it should be but it looks like a bit more material could be removed and a little more blending down in the areas circled in the attached pic.

Its a bit hard to explain but if you where to removed the manifold and look into the turbing housing you would be able to see the amount of material at the bottom (the area closet to the swing valve pivot) of the port. This can be opened up and smoothed and blended into the straight section of the port. You can also radius the inner edge of the port partially from dump pipe side and partially through the turbine inlet. I believe if this isnt down your more inclinded to get the whistle/shreak from the gate as it start to open, and obviously the exhaust gas is going to travel over a nice blend edge better than a 90deg edge. As well as reducing the possibility of cracks

Do you have a scribe? If you score a line around the flapper valve how much meat is left for the seat? I normally aim for between 1.25mm and 1.55mm, I dont think going any thinner will make it any more likely to crack (they all crack anyway!) but I feel any less than that can compromise the sealing.