Exhaust Header for 2002-2005 Nissan Sentra 2.5L SER Spec-V B15 2.5L DOHC | SPELAB

A Polished Four-Into-One Header for the B15 SE-R

The SPELAB stainless four-into-one header is intended for compatible 2002–2005 Nissan Sentra B15 SE-R and SE-R Spec V models with the 2.5L QR25DE DOHC engine. The mirror-polished B15 header brings four runners into one collector with a nominal 2.5-inch outlet and includes a four-port head gasket, outlet sealing ring and connection fasteners. Header compatibility depends on the car’s complete catalyst and sensor arrangement.

Best For

• Replacing a diagnosed manifold fault: the B15 SE-R header and required emissions components must be planned together as a compatible system.
• Refreshing a B15 SE-R front exhaust: the B15 header’s outlet seal and support points must match the retained front pipe and vehicle configuration.
• Planning a QR25DE build: selecting the Sentra header requires the actual B15 chassis and QR25DE configuration, not engine displacement alone.

Four Runners With a Single Collector

The B15 SE-R header gathers individual runners into a compact collector with sensor bosses and a flanged outlet. The polished stainless assembly provides a tubular route for a properly matched QR25DE front-exhaust project.

The B15 SE-R tubular header is not a confirmed catalytic-converter assembly. No product-specific power gain, engine-protection result or guarantee of eliminating warning lights is established for this header; the actual fault and complete exhaust system require evaluation.

Specs

What’s Included

Check the Installation section for vehicle-side seals, fasteners and connections that may need to be retained or renewed.

Vehicle & Engine Fitment

The 2002–2005 B15 SE-R / Spec V header does not cover other Sentra engines, later chassis, Altima applications or engine swaps. A shared QR25 engine designation does not establish matching pipe routing or interfaces for this header.

Before You Order & Install

• Original catalyst arrangement: the B15 header installation requires comparison of the original manifold and close-coupled converter with the proposed complete exhaust. All required catalyst functions and sensors must remain correctly accommodated; required equipment must not be removed to make a header mismatch work.
• Sensor compatibility: the B15 header’s sensor provisions must match the required sensor type, thread, sealing, position and wiring reach. A threaded boss alone does not establish correct catalyst monitoring or guarantee prevention of a warning light.
• Collector seal: the B15 header collector must match the retained front pipe in sealing-ring seat, flange angle, bolt spacing and alignment. The nominal 2.5-inch outlet alone does not establish a direct connection.
• Support and clearance: the B15 header installation requires compatible engine-side supports and clearance from the radiator, fan, wiring and hoses. The retained downstream exhaust needs its own support rather than relying on the header to carry an unsupported system.
• Fasteners: the B15 header installation requires inspection of cylinder-head studs and joint hardware before manifold removal. The four pictured fasteners do not establish a complete cylinder-head mounting set for this header.
• Intended use: the B15 header installation must retain all required catalysts, sensors and auxiliary equipment and meet applicable noise and emissions requirements. The product name does not establish road-use certification or inspection compliance for this header.

Will the ECU Need Tuning?

ECU tuning requirements for the B15 QR25DE header depend on the actual engine, sensor arrangement and complete exhaust and require a qualified technician’s assessment. No product-specific calibration data establishes that tuning is always required or always unnecessary for this header. Exhaust leaks, sensor faults and warning lights require diagnosis first; calibration cannot correct incompatible joints, poor clearance or missing required emissions equipment.

Installation Overview

This is a general installation overview. Follow the service procedure for the actual vehicle and complete the configuration and connection checks above. Professional installation is recommended.

1. Confirm the configuration and parts. Identify the B15 2.5L SE-R configuration and complete required catalyst/sensor plan. Compare the header flanges, outlet ring, support provisions and fasteners.
2. Cool and support the vehicle. Allow the engine and exhaust to cool completely. Use the correct lifting procedure with a suitable lift or rated stands on a firm level surface; never work beneath a vehicle supported only by a jack.
3. Record connections and remove the original assembly. Document sensor wires and supports. Support the retained front exhaust and remove the old manifold according to the exact vehicle procedure, preserving required equipment.
4. Prepare the joints. Inspect threads, mating surfaces, supports and retained pipes. Address damaged fasteners and clean sealing faces carefully. Match the appropriate seal and hardware to every joint.
5. Trial-fit the complete route. Fit the header loosely and align the supported front pipe with its correct sealing ring. Check support alignment, sensor reach, radiator and fan clearance and nearby heat-sensitive parts.
6. Secure and restore connections. Use the applicable tightening procedures with suitable seals and fasteners. Restore all required catalysts, sensors, supports and heat protection.
7. Check sealing and operation. Run the engine in a well-ventilated area and inspect for leaks, contact, abnormal sound and warning lights. Investigate faults before use and recheck the cooled assembly as required by the applicable service procedure.

Frequently Asked Questions

Will this fit a 1.8L Sentra or an Altima QR25?

The B15 SE-R header has no established application for a 1.8L Sentra or an Altima QR25. Its stated scope is the compatible 2002–2005 Sentra B15 SE-R / SE-R Spec V with the 2.5L QR25DE engine.

Does this include a replacement pre-catalyst?

A replacement pre-catalyst assembly is not confirmed as included with the B15 SE-R header. The complete required catalyst and sensor arrangement must be established before ordering the header.

Will the sensor bosses prevent a catalyst-efficiency code?

The B15 SE-R header’s sensor bosses do not guarantee prevention of a catalyst-efficiency code. Sensor location, catalyst operation, sealing and wiring must all remain correct, and the actual code requires diagnosis rather than masking.

Are the four fasteners a complete cylinder-head set?

The B15 header’s four pictured connection fasteners are not established as a complete cylinder-head fastener set. Original head studs and nuts require separate inspection, and each supplied fastener must match its intended joint.

Will the outlet ring seal any 2.5-inch front pipe?

The B15 header’s outlet ring is not a universal seal for every nominal 2.5-inch front pipe. The ring seat, flange angle, bolt spacing and pipe route must match the actual vehicle-side joint.

Warranty & Customer Support

A one-year limited warranty from delivery covers qualifying material and workmanship defects under normal use for the original purchaser. Proof of purchase is required. Improper installation, alteration and modification are excluded, as are installation and removal labor costs.

Returns within 30 days are subject to product condition and the applicable shipping terms. Read the Warranty & Return Policy for eligibility and claim procedures.

For fitment questions or an order issue, email service@spelabautoparts.com or call +1 888 301 8666. Hours: Monday–Friday, 9:00 AM–6:00 PM EDT. Share your vehicle year, model, engine, chosen style and relevant photos; include the order number for an existing purchase.