BMW is showing their commitment to the N63. The N63 was released in 2008 and remains in production as of 2020. However, the N63 is almost a completely different engine compared to 12 years ago. Really, the only thing that hasn't changed is the 4.4L twin turbo V8 design. Let's dive in and examine the differences between the various N63 engines.
BMW N63 Engine Codes
To avoid any confusion, the breakdown of N63 engines is as follows:
- N63B44O0 - (N63)
- N63B44O1 - (N63TU)
- N63B44O2 - (N63TU2)
- N63B44M3 - (N63TU3)
- N63B44T3 - (N63TU3)
Let's just focus on the last two characters rather than doing a full examination of BMW engine codes. The second to last characters represent output as follows:
- S - Super
- T - Top
- O - Upper (Obere)
- M - Medium (Mittel)
- U - Lower (Unterste)
- K - Reduced (Kleiner)
In this case, the N63 only features medium, upper, and top "power levels". Finally, the last digit represents technical updates (TU):
- 0 = original design
- 1 = technical update 1 (TU)
- 2 = technical update 2 (TU2)
- So on
You get the picture. The number simply represents the number of technical updates since the original design. Sorry to go off track for a moment, but hopefully this helps some differentiate the various N63's. Now, back on track.
BMW N63B44O0 - Original N63 Design
N63B44O0 Horsepower: 402 hp (300kW)
N63B44O0 Torque: 443 lb-ft (600 N-m)
Many are probably familiar with the original N63. It's almost a horror story. Actually, it is a horror story. The original N63 may be one of, if not, the least reliable BMW engines in history. BMW went as far to offer a "customer care package" for N63 owners. The N63 customer care package had dealerships look into the following issues on ALL N63B44O0 engines:
- Timing chain
- Fuel injectors
- Mass air flow sensors
- Crankcase vent lines
- Vacuum pump
- Low pressure fuel sensor
The above issues were essentially recalls even though BMW gave it another name. As such, these issues were fixed on BMW's dime, regardless of warranty. BMW also shortened the service/check-up interval to every 1 year or 10,000 miles. BMW dealerships even offered extra incentives such as trade-in cash bonuses. Long story short - these N63's had some serious common problems. Fortunately, BMW did their best to mitigate and resolve issues and keep N63 owners as happy as possible. Still, we can't imagine this was fun for original N63's.
There isn't much else to say here. Many of the original N63's on the road should be 'cured' by now. Nonetheless, be cautious if you're looking to buy an N63B44O0.
BMW N63B44O1 - N63TU Technical Update
N63B44O1 Horsepower: 444 hp (331kW)
N63B44O1 Torque: 479 lb-ft (650 N-m)
Following the disastrous start, BMW began producing the N63TU in 2012. Though still an N63, the N63TU is almost an entirely different engine. It remains a 4.4L twin turbo V8 but sees a 42 horsepower increase. However, the power gain seems to be mostly on paper. Dyno testing has shown the N63 and N63TU put down similar numbers to the wheels. The N63TU engine does show a nice boost in torque, though. Aside from the power differences, other notable changes include:
- Updated VANOS, adopted from N55
- New valve cover with updated crankcase ventilation
- Pistons updated
- Forged rods and crank
- Timing chain updated
- Oil spray nozzles for piston crown cooling
- Intake manifold updated
- MAP and charge air temperature sensors updated, adopted from N20
- Low pressure fuel sensor deleted
- New fuel injectors and HPFP
- Second coolant pump added
- Vacuum pump updated
- New turbochargers
- Addition of Valvetronic
This is far from an exhaustive list of the changes on the N63TU. Nonetheless, as we stated, this is almost a completely different engine. The list is already insane as is. Nearly every part on the N63TU was re-designed compared to the N63. As you can see, all of the problematic areas on the original N63 were updated with new components and/or designs. Additionally, the N63TU receives stronger, forged rods and crank.
Despite the similar power numbers from the factory, the N63TU should be better suited to mods and increased boost. Additionally, this was a massive reliability improvement over the N63. The N63TU is not an unreliable engine with tons of common problems. Still expect the standard BMW problems such as gasket oil leaks, cooling system, etc, especially as the N63TU ages. However, the N63TU is a pretty reliable engine overall.
BMW N63B44O2 - N63TU2 Technical Update 2
N63B44O2 Horsepower: 444 hp (331kW)
N63B44O2 Torque: 479 lb-ft (650 N-m)
Given the N63TU was a drastic improvement, the N63TU2 did not have too much to improve upon. Peak power and torque remain the same, however the N63TU2 benefits from a wider power band. This is primarily due to the switch to efficient twin-scroll turbochargers. A few of the updates include:
- Twin-scroll turbochargers
- Exhaust optimized for minimal back-pressure
- Oil/Coolant heat exchanged moved to "V" of the engine
- Partial integration of intake and cylinder head (weight savings)
- VANOS taken over from modular B series engines
Again, this is not an exhaustive list. There are some other minor updates, mostly to accommodate the above changes. Expect N63TU2 reliability to be more or less the same as the N63TU.
The N63TU2 takes another step in the right direction when it comes to modding, tuning, and increasing boost. When modded, the efficient twin-scroll turbos should add a bit of peak power with a more impressive power band. Overall, the N63TU2 is an excellent engine.
BMW N63B44M3 - N63TU3 Technical Update 3
N63B44M3 Horsepower: 456 hp (340kW)
N63B44M3 Torque: 479 lb-ft (650 N-m)
Looking at the middle output version of the third technical update, the N63TU3 receives a few performance and emission related updates. The middle output version features the same twin-scroll turbos from the N63TU2. However, it receives an "over-boost" function. This is basically BMW's way of saying the ECU is "tuned" for an increase in boost pressure. As such, the N63TU3 sees a minor bump in power. Other notable updates include:
- New higher-pressure fuel system
- Improved thermal shielding
- Valve stem seals updated
- Forged rods carried over from S63TU2
A few other updates accommodate the above changes. The higher-pressure fuel system is intended to support just over 5,000psi (350 bar), compared to the previous 2,900 psi (200 bar). Thermal shielding is intended to provide better cooling. Additionally, valve stem seals are updated with new materials to help prevent hardening.
Although power sees a bump, expect mods to have similar effects as with the N63TU2. The higher-pressure fuel system may support a bit of additional power. However, the new fuel system is mostly geared towards emissions benefits.
BMW N63B44T3 - N63TU3 Technical Update 3
N63B44T3 Horsepower: 523 hp (390kW)
N63B44T3 Torque: 553 lb-ft (750 N-m)
The top tier version of the N63TU3 is quite impressive. It produces a staggering 523 horsepower and 553 torque. Notice, this is the same torque output as the impressive S63 M engines. Updates are similar to the middle output version. Although, the upper output version gets some stronger, beefier components to support the power. Updates include:
**Also includes above TU3 updates, but we do not mention them here to avoid duplicates
- Electric arc wire sprayed cylinder walls
- Piston skirt coating
- Crankshaft re-balanced with new main bearing shells
- Forged rods from S63TU4
- Larger turbochargers with electrical blow-off valves
- Updated ignition system, taken from modular B series engines
The top power N63TU3 receives a few extra updates over the middle output version. Cylinder walls receive arc spraying for strength and durability. Pistons are coated to accommodate the cylinder walls update. The crankshaft is lightened and strengthened. N63TU3 forged rods are carried over from the 591 horsepower S63TU4. Larger turbochargers are responsible for the significant increase in power and torque. Finally, the ignition system is updated to support the new found power.
As evidenced, this update is almost all to do with power. New, larger turbos produce impressive numbers. The N63TU3 is mod happy and is a strong engine designed to handle the power and torque. Excellent update and beautiful engine.
BMW N63 Final Thoughts
From one of the least reliable BMW engines to one of the most underrated BMW engines. BMW experienced early issues with the original N63. Fortunately, customer care packages dampen the troubles. Furthermore, issues were resolved with the release of the N63TU. This engine was basically a complete re-design of the N63. The N63TU2 takes another step forward with the change to efficient twin-scroll turbos.
Finally, the newest N63 is an all around excellent engine that doesn't get the respect is deserves. The top output version makes highly impressive power with the strength to back it up. We're surprised BMW didn't put the N63 name in its past after the tragic start. Original N63's and updated N63's share few parts. However, BMW has shown their commitment to the N63. Today, it is one of the most impressive, underrated BMW engines.
Check out our N63 Common Problems post here
Learn about N63 tunes and mods here
What are your thoughts and experience with the N63? Drop a comment and let us know!