This guide will touch on some of the specifics required when you swap in the B48A20T1 aka “B48E” or “B48T1” turbo. The turbo is labelled MGT22Z on the compressor cover! This model number is important besides the OEM part number.
This turbo is found in the following cars: F44 M235iX, F40 M135iX, F39 M35iX and F60 JCW (Mini Cooper).
You may consider this swap as this turbo surpasses current stage 2 turbos for Gen 1 B48s and B48TU equipped cars (This turbo is rated up to 410HP on E85 with a twin scroll internally waste-gated 0.61 A/R turbine housing specs are very close between G25-550 and GTX2860R Gen 2).
This turbo does require a bit more retrofitting for Gen 1 B48s vs B48TU cars, B48 Gen 1 engines found in the Mini Cooper cars do require less adjustments than F series Gen 1 B48s
Please note this guide is not 100% you may experience some of the swap to not be 100% on some cars, if you experienced issues during the swap please let us know so we can add your info to the wiki: firstname.lastname@example.org
OEM Part Numbers BMW: 11658658211 11659845817 11658662074
OEM Part Numbers Garrett: MGT2256KSZ 894017-5001S 858537-5010S 858537-5007S 894017-5004S
Below is the required adjustments for F series B48 cars:
On B48TU and B48A20T01 BMW decided to move the location of this bolt hole for the flange in closer to the exhaust port, this poses an issue with correct fitment on Gen 1 B48s. Below are some photos of what our F series community member did to allow the retainer plate to hold the turbo in place. (See the Mini Cooper Guide for an alternative method):
Turbo Oil & Coolant Lines:
Turbo Oil Feed Line - Can use either “B48E” or B48 Gen1 (B48E OEM 11428629969) (B48 Gen 1 11422658749 or 11428487371 or 11427617534)
Turbo Oil Drain Line - must use B48E (OEM 11425A028A6)
Turbo Coolant Feed Line - Can use Gen 1 B48 (B48 Gen 1 OEM 11537643094)
Turbo Coolant Drain - B48E on turbo side and B48 Gen 1(B48 Gen 1 11537643226) (B48E OEM 11539488188) however the hose length needs to be modified please refer to pics below photo’s of how the turbo coolant drain line can be modified to suit:
You can then cut and slide the coolant hose over this section of the hose and use a hose clip to secure the hose, ensure you apply heat shielding to the hose to ensure it does not melt.
re-using the Gen 1 B48 Down Pipe is possible on this turbo swap.
The diverter valve found on the “B48E” is designed to remain closed when it is de-energized and open when powered. Since the B48 Gen 1 cars do not utilize a diverter valve, as a result you have 3 options:
Leave it attached to the turbo and electrically unplugged, it should remain closed under pressure.
Wire it up to a boost activated hobbs switch set to open at your maximum targeted boost pressure (consult with your tuner), this would add addition engine safety over the existing B48 Gen 1 Boost control strategy.
Remove the diverter valve and install a blanking plate, contact email@example.com if you would like their design of blanking plate. Alternatively you can have your shop fabricate something.
IPOS DV Blanking Plate:
Valve Cover Heat Shield:
The factory B48 Gen 1 heat shield that protects and deflects heat from the turbo onto the plastic valve cover has to be modified to prevent issues with interference with the wastegate actuator. To get around this issue you have 2 options:
Cut the factory Gen 1 B48 Heat Shield to suit.
Buy and install the “B48E” Heat Shield.
Heat Shield cut to fit
The turbo intake must be modified to suit the current aftermarket B48 Gen 1 Intakes including creating connections for the PCV/Vac System as you can see from the below photo the turbo inlet is vastly different to the OEM B48 Gen 1 Turbo.
We have a DIY method that a community member has made that appears to be working so far without any issues, however approaching a professional fabrication shop they should be able to create what you need to make this work. The problem with the following approach if you are not careful is creating air leaks which can affect MAF HFM readings and overall engine operation such as running to rich or to lean due to incorrect air readings at the MAF sensor.
Alternatively contact firstname.lastname@example.org for their custom made inlet/intake for this turbo as it retains factory fitment and PCV connectors as well as a MAF fitting (pictures below)
IPOS B48E Intake/Inlet
Turbo Charge-Pipe Outlet:
The Turbo outlet for the “B48E” turbo is smaller diameter and located in a different location to the OEM turbo, as such you would require a custom 90 degree bend welded on so you can reuse part of a B48 Gen 1 Charge-Pipe.
A community member reused part of the “B48E” stock Charge-Pipe (OEM 13718675264), a cut to length and beaded (the little notches/beads that stop hoses from coming off) 90 degree stainless 3inch pipe and connected to a upgraded B48 Gen 1 Charge-Pipe. (”B48E” uses a Air - to - Air Intercooler as such the Charge-Pipes cannot be fully reused on the Gen 1 B48).