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BMW B48 Engine (Design, Problems & Reliability)

Updated: Jan 21

The B48 is a 2L turbocharged inline-4 petrol engine from the BMW B-series modular engines; depending on the version, it generates 154-302 horsepower and 250-450 nm torque.


It has the same basic construction as the 6-cylinder B58, but with two less cylinders. The BMW B48 engine is the replacement for the 2.0L turbo N20 engine.


The B48 is most often found in BMW models with the suffixes 20i, 25i, 28i, and 30i. Some 35i cars from 2019 and later feature a higher power version of the B48. It may also be found in select Minis and in the fifth generation Toyota Supra.



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bmw b48 engine

BMW B48 Engine Design

The B48 is made differently from its N20 predecessor. The block and cylinder head are made of aluminium and are based on the N20. The N20 also has a twin-scroll turbocharger, direct injection, variable valve lift (Valvetronic), and variable valve timing (Dual VANOS).


The B48 is a member of the BMW engine family, which comprises 3-cylinder (B38/B37), 4-cylinder (B48/B47), and 6-cylinder (B58) engines with 500 cc displacement per cylinder.


Some of these engines are coupled with an electric motor to offer additional power and torque as required.



B48 Engine Specs

  • Manufacturer: BMW

  • Production: 2014-present

  • Configuration: Inline-four cylinder

  • Displacement: 1,998 cc (122 cu in)

  • Bore: 82.0 mm (3.23 in)

  • Stroke: 94.6 mm (3.72 in)

  • Valvetrain: DOHC

  • Timing drive: Chain

  • Compression ratio: 11:1

  • Turbocharger: Single turbocharger, twin-scroll

  • Fuel system: Direct injection

  • Fuel type: Petrol

  • Predecessor: BMW N20

  • Engine oil capacity: 5.25 liters (5.55 quarts)

  • Recommended engine oil: 0W-20, 0W-30, 5W-20, 5W-30

  • Engine oil change interval: 10,000 miles or once a year

  • Spark plug replacement interval: 40,000-60,000 miles

  • Ignition coil replacement interval: 70,000-90,000 miles



B48 Engine Problems & Reliability

The BMW B48 engine is very reliable. It's still a newer engine, so only time will tell whether regular issues occur. BMW, on the other hand, seems to be improving in terms of reliability. The B48 and B58 are more dependable than the earlier N54, N55, N63, S65, etc.


Toyota also used the B48 engine in its Supra vehicles. They did tweak the design somewhat, but it still stands as a testament to the B48's durability.



Common Problems

Other than occasional coolant leak, the B48 engine does not seem to have many frequent problems.


There aren't a lot of common failure points in this engine. After 100,000 miles, problems with the cooling system, valve covers, and oil pan gaskets may become more prevalent.



Is the BMW B48 a Good Engine?

The BMW B48 is a four-cylinder turbocharged engine that was introduced in 2015 and has been used in a variety of BMW models since then.


It has a displacement of 2.0 liters and is part of BMW's modular engine family, which means that it shares some components with other engines in the lineup.



So, is the BMW B48 a good engine? Overall, it has received positive reviews from both drivers and industry experts. It has a reputation for being reliable and efficient, with many owners reporting few issues over the long term.


The B48 engine also has a strong power output, with some versions of the engine producing over 300 horsepower.



How Much HP Can a B48 Engine Handle?

In terms of how much horsepower the B48 can handle, it is generally considered to be a robust engine that can withstand significant increases in power. Many tuners have successfully pushed the B48 beyond its stock power levels without experiencing major issues.


The BMW B48 has been pushed to well over 300hp without many issues and with minor modifications.


However, as with any engine modification, it is important to be cautious and ensure that the necessary precautions are taken to avoid damaging the engine.