This 3.5" downpipe is a great upgrade for your 2017 - 2024 GM L5P 6.6L Duramax. Replace the restrictive factory downpipe to improve exhaust flow. It's black ceramic coated and comes pre - installed with heat wrap for excellent thermal protection. The downpipe includes bungs for sensors and requires no tuning. Part Number: WCF100129. For best performance, pair it with WCFab piping kits and emissions - compliant tuning. It connects to the DOC outlet flange and mates with the OEM exhaust system front pipe using a 4 - bolt style flange connection, replacing GM Part Number 12671086.

Using this downpipe is straightforward. First, find a suitable place to work on your vehicle. Remove the old, restrictive factory downpipe. Then, connect this new 3.5" downpipe to the DOC outlet flange and match it with the OEM exhaust system front pipe using the 4 - bolt style flange connection. No tuning is required, so you can start using it right away. When it comes to maintenance, check the heat wrap regularly for any signs of wear. If it gets dirty, you can gently clean the ceramic coating with a mild automotive cleaner. For the best performance, consider using WCFab piping kits and emissions - compliant tuning as recommended.