If you're looking to boost your 370Z's performance and give it a more aggressive sound, you've probably come across the term "test pipes." In the Nissan tuning community, test pipes are a popular upgrade that replaces the factory catalytic converters for better flow and power.
What Are Test Pipes and How Do They Work?
Test pipes are straight sections of exhaust tubing that replace the OEM catalytic converters. They eliminate the flow restriction caused by the cats, allowing exhaust gases to exit more freely.
This unrestricted flow can increase horsepower and improve throttle response. Most test pipes are made from stainless steel and include fittings for oxygen sensors. Some versions, like resonated test pipes, are designed to reduce rasp and drone.
Unlike high-flow cats, test pipes contain no internal filtering media. They are intended for off-road or track use where emissions compliance isn't a concern.
Benefits of Installing Test Pipes on a 370Z
One of the main reasons enthusiasts install 370Z test pipes is to gain power. On average, a quality set can provide 5 to 15 horsepower gains, especially when combined with other bolt-ons and tuning. Removing flow restrictions like catalytic converters can significantly improve volumetric efficiency and overall engine performance.
Another benefit is sound. Test pipes give your 370Z a deeper, louder, and more aggressive exhaust tone. Many owners on forums like reddit and The370z report that it adds character to the car, especially above 3,000 RPM.
Finally, test pipes are lighter than OEM cats. Every pound counts in performance driving, and reducing exhaust weight helps with acceleration and handling.
Drawbacks and Risks of Test Pipes
Despite the performance benefits, there are trade-offs. First, removing catalytic converters will almost certainly trigger a Check Engine Light (CEL). This happens because the rear oxygen sensors detect a difference in emissions levels.
Second, the exhaust will smell like raw fuel. Without catalytic converters, unburnt hydrocarbons exit directly through the exhaust. This odor can be strong, especially in enclosed spaces like garages.
Third, sound quality may not appeal to everyone. Non-resonated test pipes often cause a high-pitched rasp or metallic buzz between 3,500 and 5,000 RPM. Several forum users caution against cheap, unbranded pipes due to poor welds and fitment.
Sound and Aesthetics: How Test Pipes Affect Your 370Z's Exhaust Note
One of the immediate effects of installing test pipes on your Nissan 370Z is the significant change in exhaust sound. Since test pipes bypass the catalytic converters, they produce a louder, more aggressive exhaust note. The result is a deeper, throaty sound that is more pronounced at higher revs. For many enthusiasts, the enhanced exhaust tone adds to the overall driving experience, offering a more dynamic and exciting sound. However, it is important to note that this increase in volume may be undesirable for those seeking a quieter ride.
Are Test Pipes Legal on the Street?
In the U.S., test pipes are not legal for street use in most states. Federal EPA regulations prohibit tampering with emissions equipment. States like California enforce CARB (California Air Resources Board) rules, making test pipes strictly illegal unless approved for emissions.
Even in states with looser inspection laws, test pipes can cause your car to fail annual emissions tests. That’s why many aftermarket manufacturers label them "for off-road or racing use only."
Installation Guide and Requirements
Installing test pipes is a bolt-on job but may require basic tools and mechanical skill. The process involves lifting the car, removing the old cats, and bolting in the new pipes. Most installations take 1.5 to 2 hours.
Because of the CEL issue, many owners also install O2 sensor spacers or use ECU tuning to disable rear O2 codes. Tuning is not mandatory, but it's highly recommended for maximum gains and smoother operation.
DIY installation is possible, but shops can do it quickly if you're not comfortable working under the car.
Final Verdict: Are Test Pipes Worth It for Your 370Z?
If you're looking for more power, better response, and a meaner exhaust tone, test pipes are a strong upgrade. They're ideal for track use or weekend builds.
But if emissions compliance or daily comfort matters, you might prefer high-flow cats or resonated systems instead.
Like most mods, it comes down to your priorities. Just know that with the right parts and setup, test pipes can help unleash the full character of your 370Z.
