Spool FX-350 Upgraded HPFP Kit [M256]

QT Parts is a Finnish online store.

Our warehouse is located in Nokia, Finland.

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The delivery time for products in stock is 1-5 business days. We ship worldwide.

If the product is not in stock and it is a pre order product, the average delivery time is 5-21 business days. If the product has a longer delivery time than previously announced, we will be in touch. International orders may be subject to VAT, import duties, and customs fees upon arrival in the destination country.

Terms for product returns:

• You must return the ordered products within 14 days of receiving
• The products must be unused and without damages
• Commission fee for handling returns is 21,90€
• For product returns, the customer is in charge of the return costs. Only door to door service (Express)
• Shipping costs are not refunded

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Return address: QT Parts, Vasarakatu 8B, 37150 Nokia, Finland.

Pre order / made-to-order products

If the product you have ordered is a pre order or made-to-order item, it is not subject to the 14-day right of withdrawal or return under consumer protection laws, as the product is manufactured or sourced specifically based on the customer’s individual order.

If you wish to cancel your order before receiving the product, we will refund 50% of the total order amount.

This condition applies to the following product categories:

• Suspension
• Engine Tuning
• Engine Parts
• Exhaust Systems
• Fueling
• Turbochargers/superchargers
• Drivetrain
• ECE-approved Downpipes

All of the above products are manufactured or sourced individually based on the customer’s order, and therefore cannot be returned after delivery, unless the product has a manufacturing or material defect.

In the event of such a defect, the standard liability for defects as provided by consumer protection legislation shall apply.

Spool FX-350 HPFP Kit | AMG M256

The Spool Performance FX-350 is the next generation high-pressure fuel pump (HPFP) upgrade for Mercedes-Benz M256 engines. This solution surpasses the previous FX-200 model in performance and efficiency, offering significantly higher operating pressure and improved fuel utilization in demanding tuning configurations.

What is the FX-350?

The FX-350 is an advanced HPFP designed to deliver significantly higher pressure and flow than stock or previous upgrade pumps.

• Operating pressure up to 35 MPa / 350 bar
• Up to +90% more flow compared to stock
• Approximately +40% more fuel through the injectors before injection limits are met
• Full E85 compatibility
• Plug & Play installation without modifications

Benefits of higher pressure:

• Improved fuel atomization
• More efficient and cleaner combustion
• Better efficiency and greater power potential

Why is an upgrade necessary?

The M256 engine's stock HPFP is a significant limitation in tuning:

• Insufficient fuel capacity for high power levels
• Limited use of ethanol blends

The FX-350:

• Significantly increases fuel system capacity
• Allows for larger turbochargers and more powerful configurations
• Expands the platform's performance potential

Package contents

• 1 x FX-350 High Pressure Fuel Pump
• Upgraded fuel lines + installation hardware
• Bosch 10 micron high flow fuel filter
• Ethanol content monitoring system with mobile app

Spool 10-micron filter

• High-level filtration without significant pressure drop
• Protects the pump and injectors from contaminants
• Optimized for Mercedes platforms

Spool Ethanol Content Monitor

• Real-time ethanol content and fuel temperature monitoring
• BLE 4.0 connectivity to mobile app
• Enables precise fuel mixture control
• PTFE core, braided stainless steel E85-compatible fuel lines

Software Requirements

• Requires software changes before commissioning
• Calibration is essential for safe and optimal operation

Spool:

• Provides necessary calibration data to the tuner
• Assists in finding an experienced tuner if needed

Note: Spool does not offer ready-made custom tunes

Important note: LPFP

The low-pressure fuel system is critical:

• Insufficient supply can cause damage to the pump and injectors
• HPFP lubrication relies on fuel flow
• Lack of fuel can lead to wear and failure

Recommendation: ensure adequate low-pressure side upgrade