Preparation for the STILLEN supercharger

Originally Posted by Kyle@STILLEN

Yup...2.5 inch is the right size unless your talking about running a lot more boost and have headers and race pipes to take full advantage of the improved efficiency. Keep in mind the amount of boost your talking about on that cobalt. 20 pounds of boost is HUGE. That is a tremendous amount of air being forced into that motor and therefore it requires a large enough exhaust to allow it to vacate effectively and efficiently. Our standard kit will probably only run around 6 or 7 pounds of boost so the dual 2.5 inch pipes are more than sufficient.

If people decide to bump up their boost pressure A LOT higher than our standard kit and support it with the exhaust components I mentioned then ya 3 inch might be ideal but for 95% of the people who buy our kits the 2.5 inch is the desired size. 3 inch piping would more than likely be too large and decrease your bottom end performance.