Eager to try something different, BMW puts the V8 platform on peripherals as it left the naturally-aspirated performance motors with the launch of its S55 engine. Apart from being the performance version of N55, S55 has a lot to boast and to prove.
We have to delve deeper into its reliability, components, technological advancements, moving parts, problems, and many more. Let’s get right to it.
What is the BMW S55?
Before we talk about BMW S55 engines, let us talk first about its predecessor, the N55 engine. Since its production in 2009, the N55 engine replaced the N54 engine and introduced in the F07 5-series Gran Turismo.
N55 is a 3.0L engine and BMW’s first straight-six engine to use a twin-scroll turbocharger. It also received Ward’s best engine awards for three (3) consecutive years from 2011-2013.
Since the arrival of the BMW S58 engine in 2015, the decline in production of N55s was decided. S58 is the pseudo-successor motor for M3 and M4 vehicles.
In 2014, BMW debuted their S55 engine, N55’s successor, for M3 and M4 vehicles. BMW, as a reputable car manufacturer, is trying to detach from naturally-aspirated performance motors.
With the comeback of six-cylinder, six inlines configuration- which are used in the previous 2nd and 3rd generation of M4 Coupe and M3 sedans; we can expect many significant changes on this engine.
S55 though coming from N55, does not share much of its features. The main difference between them is using a single turbocharger and the addition of Valvetronic (Variable Valve Lift) to improve the throttle response to reduce fuel consumption by approximately 15%.
Differences also include closed-deck engine block, lightweight crankshaft, strengthened pistons, different valve materials, twin turbos, twin fuel pumps, active exhaust, and revised intercoolers.
S55 is like N55 but on steroids. The high-performance version of the N55 engine is used for F80 M3, F82 M4, replacing the BMW S65 naturally aspirated V8 engine used in the prior generation M3.
There are six (6) versions of S55:
360HP version that appears in F87 M2 CS Racing; 405HP in F87 M2 Competition; 425HP in 2014-2018 F80 M3 and 2014-2020 F82/83 M4; 444HP in 2016-2018 F80 M3, 2016-Present F82/83 M4, and 2020 F87 M2 CS; 453 HP in 2018 F80 M3 CS and 2017-Present F82 M4 CS; and this version hops to 493HP due to its water injection system. And this engine appears in 2015-2016 F82 M4 GTS and 2017 F82 M4DTM Champion Edition.
BMW S55 Engine Specs
S55 is an inline-6, high-rev, turbocharged petrol engine.
Mainly, It was designed for performance cars. It is equipped with the new BMW’s M TwinPower Technology: two mono-scroll turbochargers that can develop up to 7500RPM, high precision direct-injection, and Valvetronic VVT, and double VANOS variable camshaft timing that provides complete control on intake valve lift.
It also allows the engine to deliver its power resulting in lower fuel consumption efficiently. These high-rev machines are responsive, insanely instantaneous to provide linear control over a wide range of varying engine speeds.
Buying anything, including cars, requires an effort to do some little research ahead of your projected purchase date. It is essential to look for information from previous generations or the current model regarding its minor or major problems.
There are no perfect cars, and eventually, whether we like it or not, issues will sprout at some point.
Crank Hub Issues
A complaint that besieged the S55 engines, that some engines produced before 2016 were failures that resulted in a spun crank hub. However, the S55 hub is the same design used for N54 and N55.
It turns out that the company TPG Tuning, which sells aftermarket crank hubs, made fraudulent claims to sell more of their products. BMW answered, and they solved it, and they also improved it.
Valve Cover and Cover Gasket Oil Leaks
The S55 valve cover and rubber gasket are the components that are more susceptible to deterioration – such as cracking and leakage that comes with years and mileage.
We all know the environment that these elements undergo, and it is undeniably harsh – high temperatures, varying pressures, and non-stop cycles. This extreme condition will eventually destroy the gaskets and result in oil leaks.
The reliability of BMW’s S55 engine is on par with its ability to express maximum satisfaction with its power and performance. It started hitting the streets six years ago and still does.
It has already proven its longevity, so it is not hard to consider it as one of those reliable motors out there.
S55 Mods and Key Features
Considered as one of the most overlooked but powerful engines that BMW made, holding the horsepower record of 1,150HP. This new engine has a slight power upgrade that toppled the V8s with its approximate 430HP, but with some FBO mods such as tune, downpipes, intake, intercooler, it can reach 600hp without breaking a sweat.
The peak torque has also been increased by over 30% and 25% engine efficiency increase. Though some people were frustrated with their elusiveness from the V8s, we can’t deny that they did the right thing in S55s.
Due to its crankcase design, optimized crankcase closed-deck, which increases its rigidity, allows cylinder pressure to push for maximized power output. And, instead of liners, the bores feature a twin-wire arc-spray coating that significantly reduced the engine’s weight.
S55s have a highly advanced thermal management system; it allows the engine and the surrounding moving parts to reduce thermal stress and other deteriorating factors.
The cooling system and engine supply are also modified to fit a track-like environment for outstanding performance. There are additional radiators apart from the main for high and low-temperature circuits, turbochargers, and transmission.
And a temperature-stabilizing electric water pump to ensure maximum and efficient performance.
With its new crankshaft design, advanced thermal management system, water-injection technology, reduced weight, modified cooling system, efficiency, and fuel economy, S55s might be one of the best engines from BMW.
Though it has some minor issues, it still outnumbers the good over the bad. This engine fits those who want a reliable and kick-in-the-back type of ride.
I hope that this clarifies some puzzles in your head on what you will buy next.