Huh??
The test pipe that comes with the THDP replaces the catalytic converter.It slips over the THDP next to the flex connector and then bolts to 4 bolt flat flange that the exhuast hangs on.Where the catalytic use to be.
Maybe your talking inside the engine bay on the turbo?If so,your suppossed to remove the elbow on the turbo and bolt the THDP to that.
HTH