B48E Turbo Retrofit - G Series Guide
B48A20T1 Turbo Retrofit Guide for B4xTU G Series vehicles.
G Series Advantage: No fabrication work required for the turbo manifold cylinder 4 mounting flange!
This guide covers the specifics required when swapping in the B48A20T1 (also known as "B48E" or "B48T1") turbo. The turbo is labelled MGT22Z on the compressor cover.
Found in: F44 M235iX, F40 M135iX, F39 M35iX, F60 JCW (Mini Cooper)
This turbo surpasses current Stage 2 turbos for Gen 1 B48s and B48TU equipped cars. Rated up to 410HP on E85 with a twin-scroll internally waste-gated 0.61 A/R turbine housing.
This guide is not 100% complete. You may experience some issues during the swap on some cars.
If you experienced issues, please let us know: [email protected]
OEM Part Numbers
BMW Part Numbers
Garrett Part Numbers
Turbo Manifold Cylinder 4 Mounting Flange
No Fab Work Required! G Series B48TU cars already have the updated manifold that is compatible with the B48E turbo mounting.
Turbo Oil & Coolant Lines
| Part | Options | Part Numbers |
|---|---|---|
| Turbo Oil Feed Line | Can use either B48E or B48 Gen 1 | B48E: 11428629969 | B48 Gen 1: 11422658749, 11428487371, or 11427617534 |
| Turbo Oil Drain Line | Must use B48E | B48E: 11425A028A6 |
| Turbo Coolant Feed Line | Can use Gen 1 B48 | B48 Gen 1: 11537643094 |
| Turbo Coolant Drain | B48E on turbo side, B48 Gen 1 on engine side (hose length needs modification) | B48 Gen 1: 11537643226 | B48E: 11539488188 |
Coolant Drain Line Modification
Cut and slide the coolant hose over the fitting section, secure with a hose clip. Apply heat shielding to ensure the hose does not melt.
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Down Pipe
Re-using the Gen 1 B48 Down Pipe is possible on this turbo swap.
Diverter Valve
The B48E diverter valve is designed to remain closed when de-energized and open when powered. Since B48 Gen 1 cars don't utilize a diverter valve, you have 3 options:
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IPOS DV Blanking Plate
Valve Cover Heat Shield
The factory B48 Gen 1 heat shield must be modified to prevent interference with the wastegate actuator. Two options:
- Cut the factory Gen 1 B48 Heat Shield to suit
- Buy and install the B48E Heat Shield
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Heat shield cut to fit
Turbo Intake
The turbo intake must be modified to suit current aftermarket B48 Gen 1 intakes, including creating connections for the PCV/Vac System. The turbo inlet is vastly different from the OEM B48 Gen 1 Turbo.
Warning: DIY approaches can create air leaks affecting MAF/HFM readings, causing the engine to run too rich or lean.
Alternatively, contact [email protected] for their custom inlet/intake which retains factory fitment, PCV connectors, and MAF fitting.
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IPOS B48E Intake/Inlet (right)
Turbo Charge-Pipe Outlet
The B48E turbo outlet is a smaller diameter and located differently from the OEM turbo. You'll need a custom 90-degree bend welded on to reuse part of a B48 Gen 1 Charge-Pipe.
A community member reused part of the B48E stock Charge-Pipe (OEM 13718675264), with a cut-to-length beaded 90-degree stainless 3" pipe connected to an upgraded B48 Gen 1 Charge-Pipe.
Note: B48E uses an Air-to-Air Intercooler, so charge pipes cannot be fully reused on Gen 1 B48.
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