Turbo placement of our new 335i T4 twinscroll has been determined. We ended up moving the turbo forward quite a bit from the original Open T4 manifold position and slightly higher as well. Routing each pulse “bank” upward before merging into the divided T4 flange will equalize runner length and allow an optimum O2 reading with the probes in these positions.
The new turbo position will still retain the original engine mount modification and will require a slight re-work of the coolant pipe out of the block. The now “centered” location gives ample room for a 4″ downpipe..
Manifold runner construction has begun. Wednesday we’ll start fitment of the dual Tial MVS wastegates and re-install the manifold with complete runners. The turbo placement change has given this twinscroll design a completely different runner configuration from before, including the changes to divide the pulses.
We’ll have updates as the setup goes back together later this week and we begin the wastegate placement!
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