Exhaust Downpipe · SKU SPAS-1207
Exhaust Downpipe for 2017-2023 Chevrolet Silverado & GMC Sierra 2500 & 3500HD 6.6L Duramax Pickup Trucks
A 3.5 inch mirror polished 201 stainless downpipe built for the 2017-2023 Silverado and Sierra 2500 and 3500HD 6.6L Duramax. It replaces the restrictive factory downpipe between the turbo outlet and the exhaust system, and ships as a single piece with a CNC machined flange. Fitment is year and model specific and does not cover Cab and Chassis trucks.
- Material201 Stainless Steel
- SurfaceMirror Polish
- Size3.5 inch
- FlangeCNC machined, chrome plated
What You Get
Key Benefits
- Opens the turbo outlet to a 3.5 inch bore so exhaust leaves the turbine with less back pressure
- 201 stainless resists road salt and heat cycling better than mild steel replacement pipes
- CNC machined flange holds sealing face flatness so the turbo joint does not weep under load
- Chrome plated flanges add corrosion protection at the bolted joint where coatings usually fail first
- Mirror polish finish photographs well for resale listings and needs no extra prep before shipping
Why Buyers Switch
Problems It Solves
- Factory downpipes choke turbo flow and raise exhaust gas temperature when towing
- Mild steel aftermarket pipes rust at the flange within a few winters of salted roads
- Poorly cut flanges leak at the turbo joint and send buyers back to the shop
- Generic universal pipes need cutting and welding, which kills shop labour margins
Where It Is Used
Application Scenarios
- Diesel truck shops upgrading tow rigs that run hot on long grades
- Distributors stocking bolt-on Duramax parts for the 2017-2023 model years
- Fleet workshops replacing corroded factory downpipes on high mileage trucks
- Online sellers who need a photographed vehicle-specific part with a clean fitment list
Buyers
Who It Is For
- Performance parts distributors buying Duramax hard parts by the pallet
- Truck accessory wholesalers serving North American light truck owners
Construction
Technical Features
- Single piece 3.5 inch downpipe with pre-fitted CNC machined turbo flange
- 201 stainless steel tube with mirror polish inside and out
- Chrome plated flange surfaces for corrosion resistance at the bolted joint
- Bolt-on replacement geometry that follows the factory routing
Data
Specifications
| Material | 201 Stainless Steel |
|---|---|
| Surface | Mirror Polish |
| Size | 3.5 inch |
| Flange | CNC machined, chrome plated |
| Package | 1x Downpipe |
| Fitment | 2017-2023 Chevrolet Silverado and GMC Sierra 2500 and 3500HD 6.6L Duramax |
| Exclusion | Does not fit Cab and Chassis trucks |
Material
Materials
- 201 stainless steel tube
- Chrome plated flange
Manufacturing
How It Is Made
Tube bending to the factory downpipe routing
Flange machining on CNC for a flat sealing face
Welding of flange to tube
Polishing to mirror finish
Test fit check against the flange pattern before packing
Checks
Quality Control
- Flange bolt pattern and sealing face checked before welding
- Weld seams inspected for pinholes along the full joint
- Surface checked for polish defects and handling marks before packing
Private Label
Customisation Options
- Private label packaging and barcode labels on request
- Bulk cartons for container orders instead of single retail boxes
Comparison
Compared With The Alternatives
| Factory Duramax downpipe | The stock pipe is quieter and emissions equipment friendly, this one trades that for a larger 3.5 inch bore |
|---|---|
| Mild steel aftermarket downpipe | Mild steel costs less per unit but corrodes at the flange, 201 stainless holds up through salt seasons |
| Universal cut-to-fit pipe | A universal pipe covers more trucks, this one bolts on without welding labour |
Installation
Use Guide
- Confirm the truck is a 2017-2023 2500 or 3500HD pickup and not a Cab and Chassis model
- Let the exhaust cool fully before removing the factory downpipe
- Replace the turbo outlet gasket rather than reusing the old one
- Torque the flange bolts evenly in a cross pattern to keep the sealing face flat
- Recheck flange torque after the first heat cycle
More In This Family
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Answers
Questions About This Part
Will this fit a 2019 Silverado 3500HD Cab and Chassis?
No. The part covers 2017-2023 2500 and 3500HD pickup trucks with the 6.6L Duramax and is not designed for Cab and Chassis trucks.
What size is the pipe?
3.5 inch. It replaces the factory downpipe from the turbo outlet.
Is the flange included or do I need to weld one on?
The CNC machined flange is already fitted. The pipe ships as one piece and bolts on.
What material is used and why does it matter?
201 stainless steel with a mirror polish. It resists the salt and heat cycling that rusts mild steel pipes at the flange.
What is included in the package?
One downpipe. Gaskets and hardware are not listed with this part number, so plan on a fresh turbo outlet gasket.
Can we get our own brand on the box?
Yes. Private label packaging and barcode labels can be arranged, and bulk cartons are available for container orders.
Is this street legal where I sell?
Emissions rules differ by market and we make no emissions approval claim for this part. Check your local regulations before resale.
Get This Part Quoted
Send the quantity you need and your market, and the reply will cover price, packing and lead time.