Homemade wastegate pressure
 

So I'm getting around to possibly using a Mitsubishi TE04H that I've had for years (I know it's not the best turbo but since I have it I'll try using it). I've never had the wastegate actuator so I kind of made my own with some allthread, a spring and some pieces I had laying around. I wanted to get an idea of how many pounds of boost the wastegate would open so I attached a 5 lb. bag of flour to the swing valve arm and adjusted the spring until it started opening. I marked it as a 5 psi setting and did the same for a 10 lb. weight. Would this be approximate to 5 (and 10) pounds of boost? Am I off base in these calculations? I've attached a photo to show what it looks like. Yeah, it's a bit trashy! As a side note, does anyone know the size of bolts or other hardware for this thing? My biggest question is on the 4 bolts that attach the swing valve housing to the turbo outlet.

https://cimg8.ibsrv.net/gimg/www.hom...c79b3bad61.jpg

This is reacting to exhaust pressure and not intake pressure. A control like this is likely to provide less pressure than the point where it opens, and will also decrease boost with engine RPM (particularly if your muffler is restrictive).

I'd grab a junkyard actuator instead.

Gotcha Matt, thanks for the feedback. Hopefully my dad will want to make a run to Pick-n-Pull in the near future!