Wehrli 17-24 Chevrolet/GMC 6.6L L5P Duramax 3.5in Down Pipe

If you're working on a 2017-2025 Chevrolet Silverado or GMC Sierra with the 6.6L L5P Duramax engine, this 3.5-inch down pipe from Wehrli Custom Fabrication is designed to replace the factory unit. The stock down pipe can be restrictive, especially after the Diesel Oxidation Catalyst (DOC), and this aftermarket part aims to improve exhaust flow right from that connection point.

This down pipe is constructed from 3.5-inch diameter tubing, which offers a straighter path for exhaust gases compared to the crushed factory pipe. It connects directly to the DOC outlet flange and is designed to mate with the front pipe of your OEM exhaust system using a four-bolt flange. It also includes bungs for your factory sensors, meaning you don't need to retune your truck just to install it. The pipe itself is finished with a high-temperature black ceramic coating and comes with pre-installed heat wrap, helping to manage underhood temperatures.

While this down pipe is emissions compliant and doesn't require tuning for basic operation, Wehrli recommends their own piping kits and emissions-compliant tuning for the best possible performance gains. Please note that this part is not CARB approved and cannot be shipped to California.