A freer-flowing exhaust path can make a VQ-powered 350Z or G35 feel sharper, louder, and more responsive without changing the full exhaust system at once. This Flashark downpipe exhaust/test pipes kit is built for listed 2003-2006 Nissan 350Z and selected 2003-2007 Infiniti G35 VQ35DE applications, replacing the restrictive factory catalytic converter sections between the exhaust manifolds and Y-pipe.
These pipes are designed for drivers who want stronger exhaust flow, a deeper tone, and better pull through the upper rpm range on an off-road or track-focused setup. Depending on the full exhaust setup, tune, engine condition, and installation quality, this kit supports an estimated 10-15 HP and 5-10 ft-lbs of torque.
Specifications
Product Type
Test Pipes
Model
DP17517-SL / MT001118
Material
16-gauge T-304 stainless steel
Finish
Polished / mirror-polished finish
Pipe Size
2.5-inch inlet and 2.5-inch outlet
Flange Type
2-bolt and 3-bolt mounting flanges
Welding
TIG-welded construction
Estimated Gain
Supports an estimated 10-15 HP and 5-10 ft-lbs of torque depending on setup and installation
Use Case
Off-road, track, and performance exhaust builds where legal
Key Features
Estimated performance support: Supports an estimated 10-15 HP and 5-10 ft-lbs of torque when paired with the right exhaust setup, tune, and installation quality.
Free-flow exhaust design: Helps reduce restriction after the exhaust manifolds for smoother exhaust movement and sharper throttle response.
VQ sound change: Adds a deeper, louder, and more aggressive exhaust tone compared with the factory catalytic converter sections.
16-gauge T-304 stainless steel: Built for heat resistance, corrosion resistance, and long-term use in a high-temperature exhaust area.
2.5-inch inlet and outlet: Designed around a 2.5-inch pipe layout to match the listed VQ35DE exhaust path.
Mandrel-bent tubing: Helps keep exhaust flow more consistent through the bends.
TIG-welded joints: Welded for strength around high-heat exhaust connection points.
CNC-machined flanges: Helps improve sealing and alignment when matched with the correct vehicle and hardware.
Included hardware: Comes with test pipes/downpipes, gaskets, and bolts for the listed application.
Why This Test Pipe Upgrade Fits the 350Z and G35 Platform
The Nissan 350Z Z33 and Infiniti G35 V35 are popular VQ35DE platforms because they respond well to intake, exhaust, catback, and tuning upgrades. The factory catalytic converter sections are built for quiet operation, emissions control, and long-term daily driving, but they can become a restriction point for owners building a louder and freer-flowing exhaust setup.
Flashark downpipe exhaust/test pipes are designed to replace that restrictive section with a freer-flowing stainless steel pipe layout. The goal is not to change the character of the car completely, but to help the VQ35DE move exhaust more efficiently, sharpen throttle response, add a deeper exhaust note, and support an estimated 10-15 HP and 5-10 ft-lbs of torque depending on the full setup, tune, engine condition, and installation quality.
Built for Better Flow and Sound
The factory catalytic converter sections on a 350Z or G35 can limit exhaust flow, especially when the car already has intake, headers, catback, or tuning upgrades. This test pipe setup reduces restriction in that section of the exhaust path, helping the VQ35DE breathe more freely through the mid and upper rpm range.
The sound change is one of the biggest reasons owners choose this upgrade. Expect a louder tone, sharper revs, and a more raw VQ exhaust note. On some setups, especially with a non-resonated or straight-through rear exhaust setup, the car may also produce more rasp or drone.
OEM Downpipe vs Aftermarket Downpipe/Test Pipe
Area
Factory Catalytic Converter Section
Flashark Test Pipes / Downpipes
Exhaust Flow
More restrictive factory layout built for quiet operation and emissions control
Freer-flowing pipe design to reduce restriction after the exhaust manifolds
Power Support
Limited by the factory catalyst section as mileage and heat cycles add wear
Supports an estimated 10-15 HP and 5-10 ft-lbs of torque depending on setup
Sound
Quieter and more muted
Louder, deeper, and more aggressive
Long-Term Restriction
Old or failing catalytic converter sections may clog or reduce flow over time
Removes that restriction point, but also removes factory catalyst function in this section
Emissions
Factory emissions equipment retained
For off-road or track use where legal
CEL Risk
Lower risk when factory parts are working correctly
Possible check engine light depending on sensors, tune, and setup
Downpipes vs Test Pipes on the 350Z and G35
On many turbo cars, a downpipe connects to the turbocharger outlet. The 350Z and G35 VQ35DE platform is naturally aspirated, so this part does not work as a turbo downpipe. On this platform, many shoppers still use downpipe, test pipe, and catless downpipe as common search terms for the same general upgrade area.
Technically, this kit replaces the factory catalytic converter sections between the exhaust manifolds and the Y-pipe. It combines the common downpipe search intent with the actual test pipe function: reducing restriction, improving exhaust flow, changing sound, and supporting better response on a performance exhaust setup.
What Is Included
2 x Test pipes / downpipes
Gaskets
Bolts and installation hardware
Shipping & Returns
Free U.S. Shipping: Orders are typically processed within 1–2 business days and delivered within 7–9 business days. Additional charges may apply to remote areas.
30-Day Returns: Unopened and unused items in their original packaging may be returned within 30 days of receipt. Return shipping is covered for verified quality issues.
Worry-Free Delivery: Optional protection against eligible loss, theft, delay, or transit damage is available at checkout.
Year
Make
Model
Engine
2003–2006
Nissan
350Z (Z33)
3.5L V6 VQ35DE
2003–2007
Infiniti
G35 (V35)
3.5L V6 VQ35DE
350Z and G35 Test Pipes Downpipe FAQs
Q1: Are these G35 test pipes or downpipes?
A1: On the VQ35DE G35 platform, many owners search this part as test pipes, downpipes, or catless downpipes. Technically, this kit replaces the factory catalytic converter sections between the exhaust manifolds and the Y-pipe.
Q2: Do these fit a Nissan 350Z?
A2: These pipes are intended for listed 2003-2006 Nissan 350Z VQ35DE applications. For 2007+ 350Z HR models, do not assume fitment without checking the correct variant and flange layout.
Q3: Do these fit an Infiniti G35 Coupe?
A3: They are intended for listed 2003-2007 Infiniti G35 Coupe VQ35DE applications. Always confirm your engine code and current exhaust setup before ordering.
Q4: Do these fit a G35 Sedan?
A4: They may fit listed 2003-2006 G35 Sedan VQ35DE applications, but 2007 and newer G35 Sedan models commonly use the VQ35HR layout. Verify the year, engine code, body style, and flange design before buying.
Q5: Are these for VQ35DE or VQ35HR?
A5: This product is primarily positioned for VQ35DE fitment shown in the listing. VQ35HR applications can use different exhaust layouts, so HR owners should confirm compatibility or choose the correct HR/G37/370Z variant if available.
Q6: How much horsepower can these test pipes add?
A6: This kit supports an estimated 10-15 HP and 5-10 ft-lbs of torque depending on the full exhaust setup, tune, engine condition, and installation quality. It is not a guaranteed dyno result.
Q7: Do I need a tune after installing these test pipes?
A7: A tune is not always required for installation, but it is recommended if you want the best drivability, fuel trims, and performance from a modified exhaust setup. A tune may also help manage check engine light behavior depending on the setup.
Q8: Will these cause a check engine light?
A8: A check engine light is possible because this kit changes the factory catalytic converter section. CEL behavior depends on the vehicle, sensor condition, tune, and local emissions equipment requirements.
Q9: Are these test pipes street legal?
A9: This is a catless test pipe setup and may not be legal for street use or emissions-controlled vehicles. It is best suited for off-road, track, or performance use where allowed by local regulations.
Q10: Will these make my 350Z or G35 louder?
A10: Yes. Replacing the factory catalytic converter sections usually makes the exhaust louder and more aggressive. The final tone depends on your rear exhaust setup, resonators, mufflers, and engine condition.
Q11: Will these add rasp or drone?
A11: Rasp or drone is possible, especially with a non-resonated, straight-through, or muffler-delete exhaust setup. A resonated or quieter rear exhaust setup can help control harshness.
Q12: Will there be more exhaust smell?
A12: Yes, a stronger exhaust smell is possible because this kit removes the factory catalytic converter function in that section. Buyers who want a cleaner-smelling, quieter setup should consider a catted option instead.
Q13: Can I use these with the stock exhaust and catback?
A13: These are designed for the listed exhaust section and may be used with compatible stock-style exhaust components when the flange layout matches. If your car has aftermarket headers or catback parts, check fitment carefully before installation.
Q14: What comes in the box?
A14: The package includes 2 test pipes/downpipes, gaskets, and bolts. Inspect all parts before installation and compare the flanges with your current exhaust layout.
Q15: Who should not buy these test pipes?
A15: This kit is not the right choice if you need a street-legal emissions replacement, want a quiet factory-style sound, cannot accept CEL risk, or own a vehicle with an unconfirmed VQ35HR, AWD, or heavily modified exhaust layout.
Every order comes with a 30-day free return, provided the item is brand new, uninstalled, and in its original packaging. We cover return shipping for quality issues. Refunds are processed within 3-5 business days. Click for Return Policy
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