BMW N55-S55 Stage 3 DI injectors

What sets Nostrum apart:

• +85% Larger than stock <20.2 g/sec vs 10.9g/sec> 
• +31% larger than EU5 M5 injectors <20.2 g/sec vs 15.4g/sec> 
• +19% larger than the stage 2 injector <20.2g/sec vs 17.0g/sec > 
• Direct Fit, no harness or spacers required 
• OEM decoupling rings pre-installed 
• Ethanol compatible 
• OEM comparable spray pattern 
• Every injector is tested statically and dynamically to ensure best quality product and set batching 
• Includes comprehensive installation guide 

They’re finally here! The long awaited Stage 3 injectors for the N55 & S55 are available. Flowing a ridiculous 85% more fuel than the stock injector while still maintaining a 250bar operating pressure rating, the Stage 3’s are what you want when you have a 4 digit horsepower goal in mind. Developed to have an OEM equivalent spray pattern, the Stage 3’s deliver unparalleled performance without sacrificing idle quality or drivability.  

Being that everything is installed like a factory part, there’s no need to worry about secondary injection controllers, filling meth tanks, clogged meth injectors, or any of the other complex solutions that remove layers of protection and safety from your engine. Our injectors operate with all the OEM ECU’s engine management system diagnostics and safety functions – resulting in a much happier and responsive system! 

Inside the box, you will find everything you need to get your new injectors installed quickly, including pre-installed decoupling rings and detailed instructions for a no nonsense install. When you are ready to tune, we can get you set up with one of our trusted certified tuners, or we have injector tuning data available for your existing dealer or tuner.  

Take your Nostrum Stage 3 injectors to the limit by pairing them with our HPFP upgrade kit, flowing an incredible 36% more fuel than the stock pumps! That additional fuel flow allows for significant torque increases earlier in the rev range, and provide the injectors with all the fuel they need to make more peak horsepower, when properly tuned. Get the best deal by bundling up! 

Every Nostrum manufactured part is backed by a limited lifetime warranty. Our products are comprehensive solutions that come complete with everything you need inside the box, including detailed installation instructions. Tuning guides are also available

Frequently ask questions:

Will these also fit an S63?

Yes, but they are batched in sets of 6. For sets of 8, see: S63 Upgraded Injectors

I see a lot of mentions about OEM equivalent spray patterns. What does that mean and why is it important?

The spray pattern of an injector (the spray geometry and its mass distribution) is designed to optimally interact with an engine air flow inside the combustion chamber to improve fuel evaporation and create a homogenous air-fuel mixture that results in a higher combustion quality. The combustion quality directly impacts the vehicle’s cold start performance, idle stability, overall drivability, NVH, knock propensity, soot and other constituent tailpipe emissions.  

The spray pattern is specific for each engine application. Installing an injector from another engine model, inevitably makes the spray distribution’s interaction with the air flow inside the combustion chamber sub optimal. This typically results in improper mixture formation leading to cold start and drivability issues, engine misfires, increased knock propensity and soot. Additionally, the wrong spray pattern can result in liquid fuel impinging in the cylinder walls, causing oil dilution and thereby increasing mechanical wear to engine components. 

• Bend Calibration
• David Shoup
• Paul Johnson Tuning
• HCP Tuning
• Cary Jordan

*Horsepower and Torque numbers are approximate and can vary significantly depending on numerous factors including what supporting upgrades are done to the vehicle, ambient temperature, elevation, road surface, tire selection & condition, fuel octane and quality, vehicle weight, and more.  The advertised numbers herein are based on optimal conditions and utilizing proper supporting modifications.  Your results may vary.