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Description
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2025Introduction Unlock the full potential of your Chevrolet Silverado or GMC Sierra 2500 3500HD 6. 6L Duramax L5P with the Downpipe Back Race Exhaust System, available for 20172019 and 20202025 models. Built from 16 gauge stainless steel and offered in 4 inch or 5 inch variants. This L5P downpipe back exhaust delivers unrestricted flow, improved throttle response and a deep aggressive tone purpose built for serious off road and competition use. Available
Introduction
Unlock the full potential of your Chevrolet Silverado or GMC Sierra 2500/3500HD 6.6L Duramax L5P with the Downpipe-Back Race Exhaust System, available for 2017–2019 and 2020–2025 models. Built from 16-gauge stainless steel and offered in 4-inch or 5-inch variants. This L5P downpipe back exhaust delivers unrestricted flow, improved throttle response and a deep aggressive tone purpose built for serious off-road and competition use.
Available Variants
- 2017–2019 GM 2500/3500HD Duramax L5P
- 2020–2025 GM 2500/3500HD Duramax L5P
Both versions feature a 4” or 5” stainless steel configuration designed to fit each model generation precisely.
Features
- 16-gauge stainless steel construction for strength and corrosion resistance
- 4” and 5” diameter options to tailor flow, tone and application
- Downpipe-back race exhaust design for maximum airflow and power
- OEM-style hangers and prewelded contour bends for accurate fitment
- Improved flanges and stainless clamps for secure, leak-free connections
- OEM-style 4-bolt turbo flange (2020–2025 variant only)
- No bungs for a clean, unrestricted exhaust path
- Fits EC-CC/SB-LB-Dually configurations (not for Cab & Chassis trucks)
- Ease of installation with all necessary hardware included
Benefits
- Boosts horsepower and torque by reducing exhaust restriction
- Lowers EGTs during towing and heavy load operation
- Improves turbo spool and throttle response
- Enhances airflow for better engine breathing and efficiency
- Produces a deep, performance-driven exhaust tone
- Built from premium stainless steel for long-term durability in harsh conditions
Compatibility
- 2017–2019 Chevrolet Silverado / GMC Sierra 2500HD–3500HD 6.6L Duramax L5P
- 2020–2025 Chevrolet Silverado / GMC Sierra 2500HD–3500HD 6.6L Duramax L5P
- Fits EC-CC/SB-LB-Dually trucks
- Not compatible with Cab & Chassis models
- 2020–2025 models must have OEM-style 4-bolt turbo flange
Technical Specifications
- Material: 16-gauge stainless steel
- Diameter: 4” or 5” mandrel-bent tubing
- Configuration: Downpipe-back, single side exit
- Finish: Natural brushed stainless
- Hardware: Stainless clamps, contour-bent hangers, prewelded flanges
- Design: Bung-free, high-flow race system
Installation & Notes
- Direct bolt-on installation using factory hanger points
- No cutting or welding required
- Must be paired with off-road race tuning for proper performance
- Professional installation recommended for best results
- For off-road and race applications only
Frequently Asked Questions
Q1: What sizes are available?
A1: Choose between 4-inch or 5-inch stainless steel versions.
Q2: Does it require tuning?
A2: Yes. Race tuning is required for correct performance and to prevent error codes.
Q3: Are all components included?
A3: Yes. Each kit includes clamps, contour-bent hangers and improved flanges.
Q4: How does it change sound and performance?
A4: Expect a deeper exhaust tone, faster turbo spool, lower EGTs and improved throttle response.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.4 ★★★★★
Based on 10 reviews
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Product Reviews
★★★★★ 5
Great Serta Chair
Color: Black
Great chair. Definitely need two people to assemble. Heavy!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 2, 2026
★★★★★ 5
Comfort and Support
Color: Grey
If you're looking for an office chair with comfort and support in mind, then this is one you should consider. Item delivered on time as stated when purchased. Assembly instructions were quite clear, just make sure all parts are accounted for when opening box. Pay attention to the supplied screw sizing during assembly per the instructions. The supplied hex key, if used, will get the assembly job done, but would recommend using a cordless drill with clutch and appropriate sized hex bit for faster and less fatiguing hand work. Just be sure to start screws by hand first to make sure they start threading into the openings so you won't cross thread the screws. Once assembled, set the chair adjustments to your liking and enjoy a very nice looking, comfortable, and supportive office chair. I especially like the lumbar support built into this product. One last note, if you are going to use this product on hard surfaced floors it is recommended that you purchase soft office chair wheels (sold here on Amazon) because the wheels supplied are hard plastic and will scratch or mar hard flooring.
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Reviewed in the United States on March 6, 2020
★★★★★ 5
Exceptional value!!!
Color: White
The chair is of high quality and is easy to put together, even for a mechanically challenged person like me!! I purchased and assembled two of them!! It is very attractive and we have gotten compliments from those who have seen them. It is extremely comfortable and I would highly recommend.
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Reviewed in the United States on June 7, 2026
★★★★★ 5
Great chair!
Color: Black
Had some issues with Delivery! But got the chair. Beautiful and comfortable. Had one once before as a gaming chair, same kind but bought it from walmart. I used to fall asleep in it all the time. Now i have it for work! One of the best chairs for the cheapest price you can get! If you want a more comfortable chair then this..... your looking at about 300 bucks. Which is next on my list!
It comes with its own screws and washers. The manual is self explanatory however you do kinda gotta play the guessing game. It's pretty simple! match the screws up with the ones in diagram. It comes with an Alan wrench. Your hand might be a bit tired tho. I advise to tighten them with super lock tight or gorilla glue so they never come unloose. And gorilla glue the bolt covers on.
Keep in mind if you use gorilla glue..... they will never come off. Lol. But as far as tighting it.... do not over tighten it. Tighten enough to where you have to put some pressure on it to turn it half way and stop.
Another tip, it's a bit of a pain to set it up with one person. If you got an extra set of hands... use em. If not.... you might be their for a bit.
Start with setting up base.
Then put arms on seat.
(Keep bolts loose but screwed in. You'll see why later when you tighten them down)
Then attach back to arms and seat.
(Now make sure bolts are in holes and tighten them down. But not at once! Do about 4 turns, move to another one. Then the other side. It's like tightening lug nuts on the wheel of a car. If you tighten one all the way down it will throw all the other bolts off and make it much more difficult to ease the bolts into the holes they go in)
Then attach seat to base.
Believe me. It's way easier if you do it like that instead of how the installation instructions say.
After that, put the caps on the holes to cover the bolts. If you don't glue them, they will pop off ..... their not..... super good. But!!!! 1 or 2 drops of gorilla glue and you never have to worry about them popping off. (They seem like they go on their tight, but they don't stay on!)
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Reviewed in the United States on March 31, 2024
★★★★★ 4
Nice chair but definitely not breathable.
Color: Black
Once I figured out the arms had a left and right...the chair was easy to put together. The faux leather is nice. The seat is (or will be once I break it in) very comfortable. I have 2 minor complaints. It is extremely straight up and down. I haven't had much chance to play with it to see if I can get it to recline even an inch. That would help. And number two, it's HOT. I'm going to have to get some sort of seat pad because the pleather is not breathable and every time I get up my bum is sweaty. I know, TMI. But all in all I think it will serve my purposes.
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Reviewed in the United States on April 16, 2026