BMW N20 Engine – 2.0L Turbo Inline-4
The BMW N20 is one of the first engines that truly established BMW’s now standard small-displacement turbocharged formula, serving as the basis for engines like the BMW B48. The BMW N20 is a 1.6-2.0L twin-scroll turbocharged inline 4-cylinder engine that was designed to take over as the primary low-mid-tier powerhouse for a number of vehicles in the BMW product line from 2011-2017. The N20 technically replaced the N52/N53 naturally aspirated straight-6 engine, marking the demise of the N/A inline-6 from BMW’s catalog.
Despite having two fewer cylinders, the twin-scroll turbocharger, in combination with other modern engine advancements including Valvetronic, direct injection, and double-VANOS, made the N20 more efficient, better performing, and more modifiable. The N20 is reliable too, outside of some early design issues with the timing chain guides. Regardless, it retained a good enough reputation to earn a spot on Wards Top 10 Engines List in 2012.
This page is the ultimate resource for everything BMW N20. We provide a general overview and technical information on the engine in addition to problems, performance modifications, FAQs, and various other resources. Whether you own an N20-powered BMW or are looking to purchase one, we have the most comprehensive N20 information on the internet.
N20 Engine Overview
The BMW N20 is a 2.0L turbocharged inline-4 engine that was used in multiple vehicle series from 2011-2017. While there is technically a 1.6L variant of the N20, the N20B16 was only released in Turkish and Tunisian markets. The N20B20 was released with multiple different variants over the years, but its engine code never changed unlike many other BMW engines.
Power output from the N20 ranged from 154 horsepower to 241 horsepower depending on the model that the engine appeared in. BMWs carrying the 18i badge, including the E89 Z4 18i and F25 X3 18i received the lowest output 154 horsepower variant. Vehicles that carried the 20i badge received a middle-tier 181 horsepower variant, and vehicles with a 28i badge received the highest-output 241 horsepower variant. The variants also differed in terms of compression, with 18i and 28i variants with a 10:1 ratio and the 20i variant with an 11:1 ratio.
The N20 is widely considered to be a reliable engine that will last many miles if properly serviced and looked after. While it had some pretty serious reliability issues early in its build cycle, mainly with its timing chain guides, post-redesign N20s are often looked at favorably in terms of long term reliability. It is also a pretty modifiable engine, as is the case with most of BMW’s other modern turbocharged engines. With the right bolt-on modifications, the N20 is capable of hitting 350whp+ power figures.
Design and Major Engine Components
The BMW N20 is constructed mainly from aluminum with both the block and cylinder head having aluminum construction. It was designed as an undersquare or long stroke engine, with its stroke being 6mm longer than its cylinder bore, making low end torque the N20’s strong suit. The N20 also uses an open deck design, meaning that coolant passages surround the cylinders, providing additional cooling. The cylinder walls are arc wire sprayed, to create a stronger cylinder wall coating. Most of the N20’s internal components are cast with the exception of the forged crankshaft.
The cylinder head design of the BMW N20 is similar to the one used on the BMW N55, albeit designed for a 4-cylinder instead of a 6-cylinder engine. As a result, the N20 features the third generation of Valvetronic variable valve lift, as introduced on the N55, and a slightly revised version of double-VANOS variable valve timing.
Arguably the most important design element of the N20 is its twin-scroll turbocharger, as the N20’s turbocharged design plays a massive role in the engine’s efficiency and performance. Instead of using a single turbo or true twin-turbo setup like the one found on other larger BMW engines like the N54, the N20’s twin-scroll turbocharger increases low-end torque, maximizes turbo response, and increases efficiency in nearly every way. The twin-scroll worked well on the N55 and carried over to the N20.
The N20 also features direct injection, which BMW had previously tested on non-US 4-cylinder engines including the N43 and N13.
BMW N20 vs B48
While on the surface, the BMW N20 and B48 seem remarkably similar, their overall construction is very different. Both engines are 2.0L turbocharged inline-4 engines with Valvetronic, double-VANOS, and direct injection, however, they are a part of two distinct engine families that differ in a few notable ways.
The BMW N20 is part of the BMW N engine family, while the B48 is a part of the BMW modular engine family. Overall, the design of the N20 is similar to other N engines like the N52 and N55, while the B48 is almost identical in design to the other engines in the BMW modular family like the three-cylinder B38 and B58 inline-6. That has an impact on strength, with the N20 featuring an open deck design compared to the B48’s closed deck design.
Most BMW enthusiasts that have driven vehicles with both engines agree that the B48 delivers power more smoothly and is the more refined engine overall, which isn’t a surprise as the B48 is significantly newer. The timing chain and VANOS were moved to the rear of the engine on the B48, reducing oscillations and vibrations which also plays a significant role in its good manners.
BMW N20 vs N26
Throughout most of this engine page, you’ll sometimes see that we discuss the BMW N20 and BMW N26 engines together and sometimes interchangeably. For the most part, the engines are very similar, almost identical in fact. However, there are a few key differences between them due to the fact that BMW had to adapt the N26 to meet stricter SULEV emissions guidelines for states that abide by them. Despite the emission-reducing changes that BMW made to the N26, BMW claims that they tuned the N26 to provide an identical power output to the N20.
In terms of overall appearance and design, the N20 and N26 are nearly indistinguishable from one another. It takes a pretty keen eye to be able to tell them apart just by looking at them. The most obvious way to tell if your engine is an N20 or N26 is by looking at the emissions sticker on the underside of your hood. If the sticker says ULEV, the engine is an N20. If the sticker says SULEV, the engine is an N26. Simple enough.
Outside of the sticker, BMW had to make some hardware changes to allow the N26 to meet the stricter guidelines. The N26 uses larger 900/600 cells/sqin catalytic converters in comparison to the 600/400 cells/sqin CATs on the N20. According to DINAN, the more restrictive CATs on the N26 throttle it a bit at peak RPM compared to the N20. Additionally, the N26 features metal fuel lines, and a slightly reworked PCV system.
All N26 engines received a electronic wastegates whereas the N20 didn’t get an electronic wastegate until mid-2012. Electronic wastegates allowed for more precise control over the earlier pneumatic wastegates.
General BMW N20 Information & Resources
N20 Engine Specs
|Displacement||1,592 cc (1.6L) – 1,997 cc (2.0L)|
|Fuel System||Direct Injection|
|Engine Block||Aluminum, closed deck|
|Valvetrain||DOHC, Valvetronic, Dual VANOS|
|Bore x Stroke||84.0 mm x 71.8 mm / 90.1 mm|
|Compression Ratio||10.0-1 / 11.0: 1|
|Torque (lb-ft)||184-258 lb-ft|
Throughout its relatively short 6-year build cycle, the BMW N20 powered quite a few cars. Despite never receiving a technical update or different engine codes, the N20B20 was released in a number of power outputs, depending on the vehicle application. The horsepower output of the N20 scaled with the badge numbers, with 18i models receiving the lowest output N20B20 and 28i models receiving the highest output N20B20 variant. Here are the vehicles that featured the BMW N20 engine:
N20B20: 115 kW (154 HP) version
- E89 Z4 sDrive18i (2013-2016)
- F25 X3 sDrive18i (2013-2017)
N20B20: 135 kW (181 HP) version
- E84 X1 xDrive/sDrive20i (2011–2015)
- F25 X3 xDrive20i (2011–2017)
- F30 320i (2012–2015)
- F34 320i GT (2013–2016)
- F32 420i (2014–2016)
- F10 520i (2011–2016)
- F10 520Li (2013-2016)
- E89 Z4 sDrive20i (2011–2016)
- F22 220i (2014–2016)
N20B20: 160 kW (215 HP) version
- F20 125i (2012–2017)
- F10 525Li (2013–2016)
N20B20: 180 kW (241 HP)
- E89 Z4 sDrive28i (2011–2016)
- E84 X1 xDrive/sDrive28i (2011–2015)
- F25 X3 xDrive28i (2012–2017)
- F30 328i (2011–2016)
- F32 428i (2014-2016)
- F10 528i (2012–2016)
- F34 328i GT (2013–2016)
- F22 228i (2014–2016)
- F26 X4 xDrive28i (2014–2017)
- F15 X5 xDrive40e (2016–2018)
In the section below, we have compiled some of the most commonly cited BMW N20 engine problems. Ultimately, the BMW N20’s reputation for reliability was tarnished a bit by timing chain guide issues on early engines. While that is unquestionably a serious concern, the N20 has shown to be a very reliable engine outside of that issue. Most of the N20’s other common problems are on par with the majority of other modern BMW turbocharged engines, with mostly wear and tear items comprising our list. Outside of timing chain guide failure on pre-2015 N20 models, valve cover gasket leaks, oil filter housing gasket leaks, and chargepipe failure are the most common BMW N20 problems to look out for.
Take a look at the dropdown menu below to learn more about these problems or check out the more in-depth problem and maintenance guides featured below.
N20 Problems & Maintenance Guides
We have the most comprehensive resources for N20 performance upgrades. This section includes some of the most popular, cost-effective, and value-focused modifications for the BMW N20 engine. Like many of the other modern BMW turbocharged engines, the BMW N20 is extremely receptive to modifications. As a result, it is possible, and relatively easy to make 350+ whp from the 2.0L BMW inline-4. From tuning information to performance parts suggestions, we have you covered as far as BMW N20 modifications are concerned.
It is also important to remember that modifications will affect different N20/N26 variants differently. For example, tuning will generally provide better gains for EWG N20s than PWG N20s. The same goes for high vs low compression variants of the N20. While all of the following mods are worthwhile regardless of which N20/N26 engine you have, expect some variation in terms of the listed performance gains.
Click on each modification to get a brief rundown of the mod, the benefits, and our best product recommendation. Additionally, we have full in-depth guides for a number of these modifications that you will find within the sections. Furthermore, a list of general performance and modification-related content can be found below, covering power limits, boost levels, and various other N20-specific topics.
Additional N20 Performance Guides
We have an extensive FAQ article that covers performance upgrades, power levels, general maintenance, problems and reliability, and more for the N20. We’ve included a few performance and reliability-related questions below but recommend reading our full FAQ guide for more extensive questions and details about the N20.
How much power can the N20 handle?
The N20 is capable of handling around 350-375whp on the stock block and internals. Anything above that and we recommend considering various internal and more advanced upgrades, especially forged pistons and rods. Overall, the N20 doesn’t have the best reputation in terms of power potential, at least when compared to other 6-cylinder engines like the N54 or B58. However, 350whp is still plenty of power from a 2.0L 4-cylinder.
How much power and boost can the stock N20 turbo handle?
While the actual limits of the stock BMW N20 turbo isn’t an exact science, it is generally concluded that around 20-22 psi is the safe limit on the factory turbo without sacrificing a ton of reliability and around 24-26 psi is the ceiling on the stock turbo. With that being said, there are always risks involved with running higher-than-stock boost pressure, so keep that in mind before cranking up the stock turbo to 11.
How reliable is the N20?
The BMW N20 engine is a pretty reliable engine. Early in its build cycle, the N20 was marred with a couple of serious issues including timing chain guide failure and oil filter housing cracks, but both of those issues were ironed out later. Other than those issues, the N20 faces similar issues to other engines in its class including oil filter housing gasket and valve cover gasket leaks. Overall, the N20 falls squarely in the middle of the reliability spectrum when compared with other modern BMW engines. It is more reliable than the BMW N54 and arguably more reliable than the N55 but less reliable than newer B-Series engines like the B48 and B58.
When did BMW fix the N20 timing chain?
BMW redesigned the N20’s timing chain guides in 2015 and timing chain issues were much less common on vehicles manufactured after that.
In-Depth FAQ Guide
8020 Media N20 Videos
Other Helpful N20 Videos
At this point, we have quite a few guides on the BMW N20 – check out all of our N20 content below or use the tabs to find our articles on specific modifications, and so on. However, there is also a ton of good content elsewhere covering the N20. Check out a few of our favorites here: