Product Description
BMW S55 Race Series Engine Build - ZNM Performance
ZNM Performance Race Series Engine Build Program
Introducing our BMW S55 engine program—engineered for M-powered inline-6 owners seeking bulletproof performance and reliability under serious boost. This page applies to all variants of the BMW S55 engine, including the S55B30T0 found in the F80 M3, F82/F83 M4, and F87 M2 Competition.
The BMW S55 is a twin-turbocharged 3.0L inline-6 with a factory closed-deck design, direct injection, and lightweight internals. While capable of supporting impressive power, common issues such as crank hub slip, rod bearing wear, and head gasket sealing problems under boost make it a strong candidate for a properly built long-block when pursuing aggressive tuning goals.
Our Race Series S55 engine builds start with complete teardown and blueprinting. We reinforce every key component—addressing crank hub failure, optimizing bearing clearances, offering optional Darton or Italian sleeves, and equipping the valvetrain for high-RPM durability. These builds are ideal for everything from 700+ WHP street cars to full-frame twin turbo or single turbo 1000+ WHP drag setups.
Our facility in Pompton Lakes, NJ builds engines for customers across the U.S. and internationally. All engines are fully disassembled, measured, and assembled in-house with final clearances precisely set by our team. Please inquire about international shipping options.
Key Features and Options for Our Built S55 Engines
- Pinned or keyed crank hub solution to eliminate OEM timing slip issues permanently
- Optional Darton MID sleeves or Italian ductile iron sleeves for high-boost, high-power builds
- Forged pistons, upgraded rods (Carrillo, Manley, IRP, MAHLE), and ARP625+ or L19 fasteners
- Balanced rotating assemblies, custom clearances based on use case and oil viscosity
- Supports 700–1000+ WHP with proper fueling and turbo systems
Cylinder Head Upgrades for Your S55
- Complete teardown, pressure testing, cleaning, and crack inspection
- Supertech dual valve springs with titanium retainers for high-RPM reliability
- GSC Power Division valve guides—ideal for high-heat, high-pressure turbo use
- Optional Inconel exhaust valves and stainless intake valves for extended abuse
- Schrick performance camshafts available—optimized for extended lift/duration and improved airflow
Upgraded Head Studs
- Choice of ARP 2000 or ARP Custom Age 625+ head studs depending on boost level and build goals
- Wagner Tuning Pro-Series studs available—engineered for high tensile strength and elevated cylinder pressure
- Critical for maintaining head gasket seal and preventing lift under high-boost conditions
Frequently Asked Questions (FAQ)
Q: How much power can the stock S55 handle?
A: Stock S55 engines typically hold 600–700 WHP with supporting mods, but bearing wear and crank hub failure become major risks at those levels. Our Race Series builds reinforce every known weak point for reliable operation at 800–1000+ WHP.
Q: What is the S55 crank hub issue and how do you fix it?
A: The factory S55 crank hub uses a friction design that can slip, causing timing misalignment or engine failure. We permanently solve this by installing either a keyed or pinned crank hub—both of which mechanically lock the timing gear to the crankshaft.
Q: Should I sleeve my S55 block?
A: Sleeving is strongly recommended for any engine targeting over 950 WHP, or if cylinder wall damage is present. Our Darton and Italian sleeves restore wall integrity and enhance head sealing for extreme boost builds.
Q: Are camshaft upgrades available for the S55?
A: Yes—Schrick offers performance camshafts for the S55 that increase lift and duration. When combined with upgraded springs, retainers, and proper tuning, they help extend the usable powerband and improve high-RPM breathing.
Q: Do you offer CNC porting or combustion chamber work?
A: Absolutely. We offer CNC porting, valve seat cutting, and chamber blending to maximize flow and detonation resistance. Each head is rebuilt with precision and tailored to your build goals.
Q: What bearings do you use and how are they set?
A: We use ACL Race, King GPC or King XP, bearings, depending on the application. All bearing clearances are set manually in-house using micrometers and dial bore gauges—never left to factory specs or generic charts. This ensures optimal oiling and longevity.