The 340i Turbo Kit is our standard big-single setup for the Gen 1 B58, and it's built the way we build all our hot parts: fabricated in-house so the packaging is ours instead of a vendor's. The manifold and downpipe are welded up here, which lets us keep the runners tight to the head and prioritize the wastegate so exhaust energy reaches boost control before it hits the turbine. We run the Turbosmart GenV HyperGate45 to keep that control honest under load.
The fittings and block adapters are machined in-house. Oil return, oil feed, the catch can fitting, and both coolant block fittings are cut for the B58, so they seat clean without stacking adapters to make something generic fit. The drain line, the 10AN oil drain outlet flange, and the 22" stainless feed line are built to the kit, not adapted to it.
We don't modify the compressor housing to make a turbo fit. That's on purpose. You can swap turbos at the track without cutting or welding, so when your combo changes the kit doesn't fight you.
