BMW 3 Owners & Service Manuals

BMW 3: Innovations B46TU/B48TU

Innovations B46TU

To meet the legal requirements for emissions, a number of technical improvements have been implemented. The technical updates for the B46TU engine include the following new features:

Innovations B46TU
New features

  1. Modified cylinder head
  2. Crankshaft weight reductions
  3. Single-part timing chain drive
  4. Modified belt guide
  5. Split cooling
  6. Heat management module with electrical Split Cooling Valve (SCV)
  7. Fuel preparation with 350 bar (5076 psi) injection pressure
  8. DME 8

Weight savings in the crankshaft drive area, injection pressure boosting in the fuel preparation area, and function changes in the engine cooling area have made it possible to reduce the CO2 emissions by 2.5 - 5%, while increasing engine performance by 5 kW/20 Nm (8 hp/15 lb-ft).

Innovations B48TU

The technical improvements made to the B48TU engine a highlighted below:

  • 302 hp (225 kW)
  • 332 lb-ft (450 Nm)
  • Reinforced crankshaft with larger main bearing diameter.
  • New piston with modified compression.
  • New connecting rods without a bearing on small end.
  • Newly developed larger exhaust turbocharger with integrated air-diverter valve.
  • Modified fuel injectors with increased flow rate and 350 bar pressure.
  • Newly developed intake air pipes for higher power and torque.
  • Modified exhaust system to minimize back pressure.
  • Engine cover with M Performance logo.


     Engine identification

    B46TU engine Engine identification - transverse mounted shown B48TU engine Engine identification - transverse mounted shown Engine number Engine identification The 7-digit engine identification

     Engine Mechanical

     Engine housing, Crankshaft drive

    Engine housing Cylinder head The cylinder head is made of aluminum. Only slight modifications have been made to the B46TU head compared to the B46. Cylinder head Crankshaft drive Crankshaft Comparis


     Direct rail

    Injector mounting Mounting bolts Plastic sleeve (not required to be reinstalled after taken apart for service) Holding clamp with bayonet fitting Rail Solenoid valve injector Casting lug The solenoid valve injectors are fastened to the holding clamp with a bayonet fitting. There is a pla

     Navigation data

    General information Navigation data is stored in the vehicle and can be updated from a USB storage device. Current navigation data is available from a dealer's service center or another qualified service center or repair shop or in the ConnectedDrive Store. Depending on the data volume, the naviga

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