Since the debut of the E39 540i in 1995, BMW has produced a 4.4-liter V8. Although the M62 was riddled with issues and needed constant attention, it produced what could arguably be, the best sounding naturally-aspirated V8 engine out there. Thirteen years later, in 2008, BMW would introduce the N63, the world’s very first “Hot Vee” engine layout, featuring twin turbos that were located directly inside of the “V” of the engine.

Much to the behest of many N63 owners, reliability was still a questionable idea, and rightfully so. However, after 14 years and numerous alterations, the N63 engine is still in production today. Taking one of the least reliable BMW engines, and transforming it into one the most underrated motors after a dozen years of updates and tweaks.

Why does this all matter? Well, when discussing an engine with spotty reliability, there may come a time when a replacement is necessary, and unfortunately for many, that time has come and gone.

This article will detail the different variations of the N63, common issues, and performance figures that serve as guide to current cost for the N63 engines on today’s market.

N63 Engine Variants

N63 Engine
Via Bimmerlife

If anything, BMW has shown their commitment to the N63 over the past dozen years, and although it has a checkered past when it comes to reliability; the numerous applications, upgrades, and alterations have transformed this engine in its entirety.

From 2008 to present day, the only qualities these engines share is the fact that they’re both 4.4-liter Twin-Turbo V8 motors. Other than displacement and the number of cylinders, these engines could not be farther from each other in terms of quality, reliability, and most of all, power output.

N63B44O0

The original N63, classified as N63B44O0 was produced from 2009-2013, and is the lead candidate to be named BMW’s least reliable engine of all time. It was such a mess, BMW even introduced a “customer care package” to help remedy the situation.

Refusing to label the service bulletin a “recall,” BMW allowed customers, in and out of warranty, to have their N63 serviced and replace the necessary parts relating to: the timing chain, fuel injectors, mass air flow sensors, crankcase vent lines, the battery, vacuum pump, and low pressure fuel sensor. The response however, was less than enthused as a class-action lawsuit was brought about the company shortly after the introduction of the service bulletin.

N63B44O1

In 2012, BMW started producing the N63B44O1, also known as technical update #1. As previously mentioned, other than being a 4.4-liter V8, it shared no similarities to the previous version. According to Bmwtuning.co, it included updates to: VANOS, valve cover, pistons, rods and crank, timing chain, oil spray nozzles, intake manifold, MAP sensor, fuel injectors, vacuum pump, and new turbos. The updates see a power bump of 42-hp as well as a noticeable amount of torque.

N63B44O2

The arrival of the next iteration of the N63, the N63B44O2, or known as the technical update #2, boasted the same horsepower and torque output, however experienced an elongated power band due to the update of more efficient twin-scroll turbochargers. The updates were less expansive, focusing on optimizing the exhaust, relocating the oil/coolant heat exchange, and a partial integration of intake and cylinder heads to save on weight.

N63B44M3/N63B44T3

2018 brought us even more updates, this time in the form of the lower output N63B44M3, and the higher output N63B44T3.The former seeing updates to the fuel system, thermal shielding, and valve stem seals. It also experienced another bump in power, capable of producing 456-hp, 12 more horsepower than the previous N63.

The latter, high output engine, saw an even bigger bump in power thanks to some more updates to the pistons, crankshaft, rods, turbos, and ignition system. These changes allowed the top-tier N63 to achieve 523-hp and 553 lb-ft of torque.

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Hot Vee Or Hot Trash?

BMW N63 V8
via: eEuroparts.com

Although the original N63 was plagued with problems, it was a monumental engineering achievement for the fact that it introduced the automotive industry to the “Hot Vee” engine layout, in a production car. Simply put, a “Hot Vee” engine has the exhaust ports facing inward.

Opposite a conventional setup, the ports point toward the center of the engine, which allows the turbochargers to be mounted between the cylinder banks. By fitting the turbos between the banks, it allows the turbos to be exponentially closer to where the combustion is occurring. This led to a dramatic decrease in boost lag since the intake and exhaust path are now much shorter than in a regular “V” engine.

However, as detailed in the previous section, these engines are not without their share of issues. Excessive oil consumption and leaking valve stems were a result of the turbochargers' location. Fuel injector failure was universal among all engines and deemed a “quirk.” Timing chains stretched easily, causing them to jump a tooth and fail quite often. Finally, batteries had to be replaced every other oil change as a result of the car charging its battery only when it coasts, unlike traditional motors that are charged by the turning of belts.

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Pricing And Availability

BMW 4.0 – 4.4-Liter Twin-Turbo N63 V8 Engine
autowp.ru

According to BMW of South Atlanta, a remanufactured engine that will fit any N63 vehicle from 2009-2017 will set you back a modest, $6,615, inclusive of the core charge. It also appears that BMW has discontinued production of the N63B4402, however, BMW of South Atlanta offers the higher output, N63B44T3, for an astounding $24,222.29 with the core charge.

Due to the many factors surrounding the engines' integrity, it can be quite difficult to find a good example of a used N63 in today’s market. Coincidentally, as a result of becoming more reliable, too new into their production lifespan, or discontinued altogether, it can be quite difficult to find the refreshed models at anything less than retail.