After developing the first turbo manifold design for the Horsepower Freaks 335i single turbo-kit, some changes were necessary to attain proper tuning feedback for their ECU parameters. While making these changes, we promoted a twinscroll version for the next design giving benefits across the board; including the tuning portion being addressed.


A pair of open atmosphere dumptubes were aligned to the Tial MVS wastegates alongside of the 3″ turbo-back exhaust..


There really isn’t much room around the exhaust bank of the N54 engine, so this manifold design has completely changed from the original test-piece to implement the divided turbine housing and now Dual Tial wastegates. The new design allows direct control of the front and rear engine “banks” (cylinders 1-3 and cylinders 4-6) for the wastegate/boost controller and equalizes exhaust flow with equal-length runners feeding into the turbocharger.



The car is now back together for continued development on the computer system for the single turbokit. Visit Horsepower Freaks for your 335i upgrades!


Written by John Pham — February 18, 2015