Porting the wastegate

[ccb056]

Good Pics HJ.

When mine was ported the turbine casting was removed from center housing to prevent any chips from falling back into the blades. Took a bit of heat to separate the two after removing the bolts, its a tight fit.

This was ported out to 21.5 mm? Do you think you could have gone further?

[HJ2]

With a cloth and all openings taped and help of gravity, i don't think it is necessary to unbolt the housing.
Mine is running fine anyway after porting it this way

I ported with a 21mm stone. In order to keep the stone running i rotated the power drill a tiny bit in my hands, so there is always a little free play for the stone.
That's how i ended up with 21,5 mm.

I can measure if there is slack for a bigger port without changing the flapper plate tonight, but don't expect it to be much!
Also you need to find a grinding bit with the correct diameter. That won't be easy, but 21mm is easy to find!

Any other diameter than 21.0 ... 21.5 can only be obtained in a controlled way on a milling machine.
However my turbo housing was harder that the expensive tooling i used, so i ended up using the grinder in the end as well

[Peter_W]

Good Pics HJ.

When mine was ported the turbine casting was removed from center housing to prevent any chips from falling back into the blades. Took a bit of heat to separate the two after removing the bolts, its a tight fit.

This was ported out to 21.5 mm? Do you think you could have gone further?

I went 22mm on mine as my exhaust had been opened to the higher end of the scale (PCE, 2 1/2" with mandrel bends, flanged section to substitute for the cat) I'm very pleased with the result - no boostcreep or overboost.

[HJ2]

I Checked again Yesterday and i would say that with my flapper, the maximum safe port size is 21.5 mm.
This due to the radial free play of the flapper.

So with my particular turbo anything above 21.5 mm requires a bigger diameter seal.
With a bigger diameter seal you can go a lot bigger!