Downpipe Exhaust For 2003-2007 Nissan 350z/G35 | SPELAB

Who This Is For

2003-2007 Nissan 350Z (Z33) and 2003-2007 Infiniti G35 (V35) owners with the 3.5L VQ35 V6 who want a higher-flow downpipe / test pipe for the naturally-aspirated VQ.

Key Features

• 2.5" piping for the full VQ35 system
• Direct bolt-on to factory or aftermarket headers
• TIG-welded stainless steel construction
• Increases exhaust flow for the naturally-aspirated VQ35
• Fits all 350Z and G35 Coupe/Sedan models

Product Specifications

• Engine: Nissan VQ35DE / VQ35HR 3.5L V6
• Inlet Size: 2.5 inch
• Outlet Size: 2.5 inch
• Piping Diameter: 2.5 inch (63.5mm)
• Material: Stainless Steel
• Surface: Mirror Polish
• Configuration: Catless
• Flange Type: Bolt-on (4-Bolt triangular)
• Weight: 4.06 kg (4060 g)

What's Included

• Downpipe
• Gasket(s)
• Mounting hardware

Check Before Choosing

• Engine variant: Fits VQ35DE and VQ35HR variants. Verifies your specific engine code before ordering.
• No tuning needed: This is a naturally-aspirated engine — no tuning is required.
• VQ rasp / hiss: Removing the catalytic converter deepens the exhaust note but can introduce VQ "rasp" at high RPM. Consider pairing with a resonated mid-pipe.
• Street legality: Off-road / race use only. Check local laws regarding cat replacement on street-driven vehicles.

Vehicle Fitment

Compatible vehicles: Nissan 350Z, Infiniti G35 Sedan, and Infiniti G35 Coupe (2003–2007).

Installation Guide

Pre-Installation Checklist

• Confirm your engine code and model year match the fitment list above
• New gaskets and mounting hardware ready
• 22mm slotted O2 sensor socket + PB Blaster on hand (if applicable)
• Penetrating oil on hand for seized exhaust bolts

Installation Steps

1. Lift the vehicle and secure it on jack stands
2. Spray exhaust bolts with PB Blaster and let them soak for 30+ minutes
3. Remove the factory downpipe / Y-pipe section
4. Discard the old gasket and clean the mating surfaces
5. Install the new downpipe / Y-pipe with a fresh gasket
6. Tighten all bolts to factory torque spec
7. Start the engine and check for exhaust leaks

Installation Notes

• Never reuse the old gasket — it will cause an exhaust leak
• Verify all O2 sensor bungs are properly plugged or fitted with sensors
• Expect a more aggressive exhaust note and a slight drone change
• No tuning required for naturally-aspirated applications

FAQ

Does it fit VQ35DE and VQ35HR?

Yes — both 3.5L VQ variants share the same downpipe flange geometry.

Do I need a tune?

No — the VQ35 is naturally aspirated. No tuning required.

Will it cause exhaust rasp?

Removing the catalytic converter can introduce VQ "rasp" at high RPM. Consider pairing with a resonated mid-pipe if rasp is a concern.

Is it street-legal?

Off-road / race use only. Check local laws regarding cat replacement.