MagnaFlow 4in Turbo Downpipe - GM 6.6L Duramax 2001-2007

MagnaFlow 4in turbo downpipe (PN 15399) for the 2001-2007 GM 6.6L Duramax diesel (Chevy Silverado / GMC Sierra 2500 HD & 3500). Mandrel-bent from corrosion-resistant stainless steel on CNC robotic equipment, the larger 4in bore frees up exhaust flow off the turbo. Professional install recommended.

Specifications

This part fits:

Shipping

• In-stock orders placed before 3 PM EST ship the same day — everything else ships within 24 hours.
• Standard, expedited, and overnight options at checkout.
• Oversized items ship by freight and take longer.
• Backordered items ship as soon as stock lands — contact us for lead times.
• International orders: prices do not include VAT, duties, or import fees. Your country charges these at import and they are the buyer’s responsibility.

Returns

• 30-day returns on new, uninstalled items in original packaging with all hardware.
• Standard returns: 8% restocking fee, buyer pays return shipping. Both waived if the item is defective or we made the error.
• Installed or used parts can’t be returned — confirm fitment before you install.
• Special orders and custom items are final sale.
• Email us for return authorization before shipping anything back.

Full details: Shipping Policy · Refund Policy