From 3.0L to 3.4L: The Next Chapter Begins for Grimace
For the last two years, our promotional BMW G81 M3 Touring - Grimace - has served as EuroWerke’s dedicated in-house S58 development platform.
From bolt-on performance packages through to hybrid turbocharger setups, Grimace has played a major role in shaping our understanding of the S58 platform.
In its most recent configuration, the car was pushing close to 1000 horsepower on the factory engine and stock block - an impressive milestone, but also a clear indication that we had reached the upper limits of what the standard platform could reliably support.
Now, it’s time for the next step.
Why Move Beyond the Factory S58?
At EuroWerke, development has always been about progression.
After years of testing and building some of Australia’s fastest Stage 1, Stage 2 and Stage 3 S58-powered BMWs, we believe we’ve established the ideal combinations for customers looking to extract the most from the stock engine platform.
But development doesn’t stop there.
The next phase is about understanding where the platform can go beyond factory displacement - not only for our own testing, but to validate the products and packages we are willing to stand behind and supply to customers moving into more serious power levels.
That next step begins with capacity.
The Move to 3.4 Litres
For Grimace’s next chapter, the factory 3.0L S58 is being transformed into a fully built 3404cc stroker engine, based around the proven 5150 AutoSport Bully Stroker Kit.
This package utilises an 85mm bore configuration, increasing displacement to 3.4 litres and creating the foundation required for significantly greater torque, improved turbocharger response and a much higher power ceiling.
The bottom-end specification includes:
- 5150 4340 billet steel stroker crankshaft
- CP-Carrillo Pro-Xtreme connecting rods
- CP-Carrillo forged pistons
- Heavy-duty wrist pins
- CP-Carrillo piston rings
- Upgraded cylinder sleeves
- Fully balanced rotating assembly
At these power levels, precision and preparation become critical.
Machine Work and Block Preparation
To support the next phase of Grimace’s development, the S58 block has undergone substantial machine work and reinforcement.
This includes:
- CNC cylinder sleeving
- Precision boring, honing and decking
- Oversized head stud installation
- Fire ring machining
- Minor internal block clearancing for stroker crankshaft clearance
Importantly, the S58’s factory closed-deck block design remains one of the strongest foundations in modern BMW performance engineering, allowing us to build on an already capable architecture without the need for additional block reinforcement.
Combined with upgraded fasteners and a fully balanced rotating assembly, this new bottom-end package creates the foundation required for the next stage of development.
Why Single Turbo?
With Grimace previously running hybrid twin turbochargers and producing over 650kW, the next logical progression was clear.
Single turbo.
The decision wasn’t made purely for power.
Moving to a single turbo configuration allows greater efficiency at higher airflow demands, improved top-end power potential and a completely different power delivery characteristic - while also delivering the unmistakable sound and presence that comes with a properly engineered single turbo setup.
The full turbo system will be covered in detail in the next article.
Built, Strengthened and Tuned In-House
What makes this project different isn’t just the hardware.
It’s where it’s being built.
Unlike many high-horsepower builds, Grimace is being developed entirely in-house at EuroWerke.
From engine assembly and transmission strengthening through to fabrication and final calibration on our Mainline ProHub 3600CS AWD Hub Dyno, every stage of this build remains under one roof.
That process matters.
Because at EuroWerke, we believe the best way to stand behind the products and services we offer our customers is to test, build and validate them ourselves.
That’s exactly what Grimace has always represented.
Build Progress
✅ Chapter 1 - Bottom End: From 3.0L to 3.4L (current)
⬜ Chapter 2 - Head Assembly
⬜ Chapter 3 - Gearbox & Transfer Case Build
⬜ Chapter 4 - The Single Turbo Transformation
⬜ Chapter 5 - Everything Behind the Power
⬜ Chapter 6 - Engine & Gearbox Reunited
⬜ Chapter 7 - First Start, Cal
What Comes Next?
This is only the beginning.
With the bottom-end now complete, the next phase of the build will focus on cylinder head preparation and assembly before moving into the single turbo conversion and supporting systems.
The goal?
To build a platform capable of competing with the fastest G81 M3s in the world - while creating a repeatable, proven package we can offer our customers with complete confidence.
Follow along as Grimace enters its next chapter.
EuroWerke - Sydney’s S58 Performance Specialists.
The beauty is in the details
Frequently Asked Questions
Why stroke the BMW S58 engine to 3.4L?
Increasing the S58 from its factory 3.0L displacement to 3.4L improves overall torque, turbocharger response and airflow capacity. For high-horsepower applications, additional displacement helps improve spool and broadens the powerband.
How much power can a built S58 engine handle?
A properly built S58 with forged internals, upgraded sleeves and the correct supporting systems can comfortably support well over 1000 horsepower. Final limits depend heavily on turbocharger setup, fuel system and calibration.
Why switch from hybrid turbos to a single turbo on the S58?
Single turbo setups offer greater efficiency at higher power levels, improved top-end power potential and simpler airflow management compared to hybrid twin turbo systems. They also create a completely different sound and power delivery.
What is required to build a 1000+ horsepower BMW S58?
Building a four-figure S58 requires far more than tuning alone. A forged bottom end, upgraded sleeves, transmission strengthening, fuel system upgrades, cooling improvements and proper dyno calibration are all critical.
Can EuroWerke build and tune custom S58 engines?
Yes. EuroWerke specialises in BMW S58 performance development, offering in-house engine building, transmission strengthening, custom fabrication and dyno tuning for high-performance BMW applications.
