Power Gains

Let's face it, removing the cat isn't going to be like a shot of nitrous. However, we find this modification to be very worthwhile. Years ago we did a back to back test and found peak gains of 5whp and 6wtq on a normally modified all-motor VR6. Those numbers are certainly worthwhile in a detailed all-motor build. Even larger power gains can be had on supercharged or turbocharged car. Of course, individual power gains depend on the condition of the catalytic converter removed, the exhaust system used, and the condition of the motor. We wouldn't build them if they didn't work.

The Sound

The resulting sound of a test pipe also depends on the exhaust system used. Overall, adding a test pipe increases the volume of the exhaust note while also providing a much sharper sound. For example, when using a Magnaflow 2.25" cat-back exhaust system the volume of the exhaust note increases some at idle and cruising while becoming significantly louder at higher RPMs. Idle and low-load cruising attract little additional attention to the vehicle. High-revs and aggressive driving are obviously louder activities. Inside the car all low rpm 'drone' disappears. The exhaust note can be heard, but does not drown out the radio or conversation.

Legality

• For off road racing and testing purposes only!
• Read & understand local laws and emissions testing requirements before purchasing. In many states it is illegal to remove emissions components. Emissions compliance is the sole responsibility of the vehicle's owner.
• May cause 'catalyst below efficiency' fault code and / or check engine light (CEL) to illuminate in the instrument cluster.

2.5" Through Test Pipes - Fitment Details

By popular request our test pipes are now available in 2.5" through. These pipes fit exactly like the original but lack the reduction to stock band clamp size. This allows for a straight-through fitment when using 2.5" exhaust. Our 2.5" through test pipes terminate at the center of the stock band clamp. Many 2.5" cat-back exhaust systems for the mk3 VR6 have a built in reduction to the stock band clamp size. In this case, the cat-back exhaust system will need to be modified. The reduction will need to be removed, a 2.5" section of pipe added and a 2.5" band clamp added. Many cat-back exhaust systems begin at the center of the stock band clamp as 2.5". In this case no modification is required and a band clamp should be used. Due to the variances in aftermarket cat-back designs we cannot guarantee a 100% bolt-on 2.5" through test pipe for any or all aftermarket exhaust systems.