engine on the stand and the turbo in place. I created my own restrictor by taking a male fitting and welding it shut. Then take a fine drill bit and drilling a hole in it. I can't remember the exact size but you want around .035 of an inch. or under 1 mm. for the feed line going into the turbo. Never heard of restrictor on the return. The return on the turbo is suppose to be gravity drain. There should be no restiction. Just like the stock turbos. You will want to get the exact spec for the restriction size from HKS or a garret turbo distributor .
