Poor Acceleration At Lower Rpm

[gibby]

I have a 2004 996 C4S and I put in Fab speed 996 Sport Catalytic Converter X-Pipe and now the acceleration is not as brisk as it could be till it reaches 3500 rpms and then it kits in and is very fast. What would cause this? There are no faults in the computer.

[number9ine]

I have a 2004 996 C4S and I put in Fab speed 996 Sport Catalytic Converter X-Pipe and now the acceleration is not as brisk as it could be till it reaches 3500 rpms and then it kits in and is very fast. What would cause this? There are no faults in the computer.

Exhaust backpressure can affect the torque characteristics of your car, which is why the stock exhaust is tuned carefully to optimize power delivery in all operating states. Any modification to that may yield extra power in one state while robbing your car of power in another.

If you replace with the stock part, does the problem go away? That's your first troubleshooting step. If re-fitting the stock exhaust solves the issue, then it's a matter of deciding whether you want that extra power up top, or reliable power across the board. I'd choose the latter.

Mark