Porting wastegate hole? Why do it?

You only need to port the waste gate bypass hole if you experience boost creep, to control boost. When I installed a Dutt neck on my stock intercooler I had boost creep with my stock turbo, I didn't want to port the waste gate hole in case I wanted to bring my GN back to stock, so I bought a used ta49 and ported the waste gate hole to .950 and everything is fine.
 
Rather than just make the hole diameter bigger, you can make the stock sized hole flow more by putting a radius on the inside.

A square sided hole in a flat plate only flows 66% of a hole with the same throat diameter that has a proper radiused venturi leading to it.

Most Wastegate holes are as square sided as they come.

Doing it this way keeps you from making the hole larger than the puck.
 
Boost control...stock turbo doesnt need it
Can you elaborate on this a little more? I would like to understand this better. I haven't really understood when this needs to be done or when it doesn't. Im running a stock turbo but I'm planning on building a new down pipe. I noticed a lot of downpipes have a extra large puck in them for ported holes. When i build my downpipe I was considering adding a extra large puck as well, but I don't really know why I would need it, or what effect it would have to increase the size of this hole. I plan on going to a te44 turbo in the future.
 
Just run the turbo and if you have boost creep then port the wastgate hole and leave .050 around the edge for the puck to rest on. TE44 typically doesnt boost creep.

Bit of advice...... take the time and do research on areas and stuff your curious about the board here has a ton of info.
 
If the turbo is selected based on a target horsepower (mass flow) and the target hp is close to the maximum mass flow of the turbo little to no porting of the hole is needed. If you over do it you just made it easier for the ex pressure to push it open and can expect boost drop off when you start working it up near it's potential. I still have never needed to go larger than 1.1" on anything I've done
 
I had my motor stroked and ported with roller Cam then reinstalled my te60 and couldn't get boost lower than 19 with standard wastegate so I ported it to 1.125 and now it is at 10 with 1/8 preload on wastegate
 
If the turbo is selected based on a target horsepower (mass flow) and the target hp is close to the maximum mass flow of the turbo little to no porting of the hole is needed. If you over do it you just made it easier for the ex pressure to push it open and can expect boost drop off when you start working it up near it's potential. I still have never needed to go larger than 1.1" on anything I've done
I thnk thats whats going on with mine. Its ported so much theres a spot where it looks like exhaust is blowing past the puck (lmk what you think Bison). When I still had the stock turbo on my car I did experience some boost creep. A mbc fixed that problem. Made the car fun as hell on the street too.
 
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