Wikiページ 'Cat Back Exhaust System for Toyota GR86, FT86, FR S, Supra, & Subaru BRZ' の削除は元に戻せません。 続行しますか?
Most designs of the time therefore included secondary air injection, which injected air into the exhaust stream. This increased the available oxygen, allowing the catalyst to function as intended. Cat-back exhaust systems replace every component behind the catalytic converter, including most piping, mufflers, resonators, and tailpipes.
The cat back system’s pipes have a larger diameter than a standard set. So, your vehicle will get to perform better at a fraction of the work it outputs. An 
Wikiページ 'Cat Back Exhaust System for Toyota GR86, FT86, FR S, Supra, & Subaru BRZ' の削除は元に戻せません。 続行しますか?