Hey, I need to know the size of both wastegate holes on a S5 turbo. I'm going to port it tomorrow but don't know what size bits to get. Also, would there be any ill effects of making the holes too big? Maybe more turbo lag because the wastegate is letting out too much exhaust? Thanks.

 

As long as the flapper door covers the hole you can hog it out all you want.

You can actually go past the flapper door, but you'll get some bad boost lag probably. I've heard of people porting past the flapper door before, as long as the door coveres 75%-80% it's still alrigt from what I have heard. I could be wrong though, search for some info if you wanna just double check.

 

Cool, thanks for the info.

 

http://fc3spro.com/TECH/HOWTO/KWG/kwg.html

 

Yeah, I've already read the How-To on there but it doesn't say anything about the size of the burr and what-not. Thanks anyways though.

 

Are size burr will do, generally, just keep moving in a circle. Typically, a larger diameer burr will help keep a first-time porter from creating ruts, but a wastegate is pretty hard to mess up.

You might want to buy the 6" long burrs for this job (and you will want to use an air grinder), to keep the grinder from bouncing off the flapper door when you're porting the right hand side of the wastegate holes. It'll also help for cleaning up the casting in the lower wastegate hole.