Fitment wasn’t the greatest could improve a lot
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2026
6.6L Duramax L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
Regular price
$357.50
Regular price
$467.50
Sale price
$357.50
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GM Duramax L5P (2017 - 2026)
6.6L Duramax L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
6.6L Duramax L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
SKU: SKU:EP-GM-L5P-DP
Regular price
$357.50
Regular price
$467.50
Sale price
$357.50
Quantity
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Introduction
This L5P downpipe is a 3.5' turbo direct downpipe made for 2017-2026 GM Duramax 6.6L L5P pickup trucks. It bolts directly to the turbocharger and replaces the factory downpipe that contains the DOC (Diesel Oxidation Catalyst) filter.
Removing the DOC right after the turbo allows exhaust gases to flow out faster. This helps the turbo spool quicker, reduces exhaust restriction and improves overall engine performance. This downpipe is commonly used on off-road and competition trucks where maximum exhaust flow is needed.
Technical Specifications
| Pipe Diameter | 3.5 inches |
| Material | High-grade T409 stainless steel |
| Flange Style | 4-bolt turbo flange |
| Studs | Two pre-installed turbo studs |
| Finish | Raw stainless with heat wrap included |
| Design | Turbo-direct DOC delete downpipe |
Vehicle Fitment
| Year | Make | Model | Engine | Body Type |
|---|---|---|---|---|
| 2017 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2018 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2019 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2020 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2021 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2022 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2023 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2024 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2025 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2026 | Chevrolet | Silverado 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2017 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2018 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2019 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2020 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2021 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2022 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2023 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2024 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2025 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
| 2026 | GMC | Sierra 2500HD / 3500HD | 6.6L Duramax L5P | Pickup Truck |
Why an L5P Downpipe Replaces the Factory DOC
On GM L5P Duramax engines, the DOC is positioned immediately after the turbocharger. While necessary for emissions compliance, it creates a major restriction in the exhaust path. Installing an aftermarket L5P downpipe is the primary method to remove this restriction at its source.
A larger 3.5' Duramax down pipe allows exhaust gases to exit the turbo more efficiently, reducing backpressure while improving throttle response, turbo sound and engine efficiency. This modification is commonly performed as part of a complete L5P delete exhaust system intended for off-road or competition use.
Because the DOC is an emissions-controlled component, professional custom tuning is required after installation to prevent check engine lights and ensure proper engine operation. This product is not emissions compliant and is not legal for street-driven vehicles.
L5P Downpipe Features
- 3.5' stainless steel L5P turbo downpipe
- Approximately 20% improved exhaust flow over the factory Duramax down pipe
- Completely removes the factory L5P DOC
- Heat wrap included to reduce engine bay temperatures
- Improved heat retention for stronger exhaust velocity
- 4-bolt turbo flange with two pre-installed studs
- Built for maximum flow in off-road and competition applications
- 2020+ trucks may require minor hanger adjustment
Benefits
- Reduced exhaust restriction directly at the turbocharger
- Improved turbo response and throttle feel
- Lower exhaust backpressure under towing or heavy load
- Supports higher horsepower and torque with proper tuning
- Enhanced turbo sound compared to the stock L5P downpipe
Installation & Notes
- Bolt-on installation at the turbocharger using the factory mounting location
- Basic hand tools required
- Designed to work with DPF delete pipes and full exhaust systems
- Custom tuning required
- For off-road and competition use only
Frequently Asked Questions (FAQ)
What does an L5P downpipe do?
It replaces the factory turbo outlet pipe and removes the L5P DOC to improve exhaust flow and turbo response.
Do I need this for a full L5P delete exhaust?
Yes. Most delete exhaust systems do not remove the DOC. This downpipe is required to fully eliminate it.
Will this cause a check engine light?
Yes, without proper tuning. Professional custom tuning is required after installation.
Is this street legal?
No. This product removes emissions equipment and is intended for off-road use only.
Years: 2017-2026
Make: GM
Model: Duramax
Engine: L5P
Body: Pickup Truck
Make: GM
Model: Duramax
Engine: L5P
Body: Pickup Truck
Shipping Policy at Tuner Depot
At Tuner Depot, we understand the importance of timely delivery for your performance parts. We're committed to ensuring a seamless shipping experience, striving to dispatch your orders with utmost efficiency and speed.
Our Shipping Policy: Our aim is to dispatch all orders within two business days, providing you with a quick and efficient processing time. However, unforeseen circumstances beyond our control may occasionally impact shipping times.
Factors Affecting Shipping:
- Weather Conditions: Adverse weather conditions such as rain, snow, or sleet may affect delivery timelines. We will make every effort to minimize any delays.
- Holiday Periods: Please note that our shipping center will be closed during holidays. We will resume shipping promptly on the next business day. Allow for potential delays during peak seasons, but rest assured, we will keep you informed every step of the way.
- Staff Availability: Unforeseen circumstances can occasionally affect our staffing levels, possibly leading to minor delays. We are committed to swiftly resolving any issues to maintain our high standards of service.
We genuinely appreciate your understanding and patience during any unexpected obstacles. Be assured that we will utilize every resource available to deliver your performance parts promptly.
Warranty
Hardware components are covered by Tuner Depot's standard warranty. Tuning devices and software carry manufacturer warranty terms. Use of these products will void your vehicle's factory warranty. Please confirm with your manufacturer before installation.
Off-Road Use Only
These products are intended for off-road, race, and competition use only and may not be legal for use on public highways where emissions laws apply. Check your local and state regulations before purchase.
Customer Reviews
Overall rating: 4.6 / 5 from 171 reviews.
Tuner depot was very helpful I thought I screwed up on the tune part and flashing the ecm but there customer service told me I didn’t mess it up and helped me through it but one thing for sure is nothing to do with tuner depot but no one every tells you on a first time doing one of these trucks the amount of hours it takes it took me almost 30 hours which if I had the right tools and confidence I could of probably cut it down to about 20 but kit works great it’s got awesome power now and I’ll be doing the down pipe very soon to I highly recommend just buying it and getting it over with because the truck is still very quiet almost like it’s a notch above stock
GM Duramax L5P All-In-One DPF/DEF/EGR Delete Kit (2017-2025)
Just got them installed on my truck yesterday and cannot believe the increase in performance! Can’t wait to take it on a road trip already see more power increase and fuel mileage. Unbelievable would do it again tomorrow!
Love the sound of the straight exhaust especially on the Dirtymax they just sound badass without a muffler
I purchased the efi live sotf tunes along with Dpf delete kit, dpf was good quality, tuner worked with me and not only sent my autocal loaded with a sotf tune but also sent me a few single tunes to use until I installed the switch, the only negative was that 130hp was the max power tune single or switch on the fly, but over all I was pretty happy and service was very good throughout.
Works s expected
Great product
Timely delivery, great product NOT cheap junk.
L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
Thank you!
Great communication
Sounds great easy installation
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2026
Did not fix on the fling correctly where the downpipe sits and was pushing upwards towards frame
6.6L Duramax L5P CAT & DPF Delete Pipe | 2017–2026 GMC/Chevy
Pretty straight forward install
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2026
Helped quiet down the straight 4" pipe
Should come with clamps
Everything went smooth and lined up great just wish it would’ve came with instructions
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2026
Customer service absolutely sucks!!!!
Great product
L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
Worked and fit as expected
Perfect sound
Could have come with some kind of directions. Made it through it ok but a little direction would have been nice. Overall everything works as it should.
Sounds great not to loud
Before installing never had a code after install getting low fuel rail pressure code under load. If I keep RPMs up just a little ( by switching to manual shift and never come out of 5 gear Allison 6 speed trans) will work fine . If u shift to 6th gear lower RPM as soon as u go up a little incline it starves for fuel and goes into reduced power mode. But if u mash the excelsior and down shifts it will take off like a rocket.
Worked perfectly.
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2025
Sounds good.
I received a product that was very different from what I ordered, and I have tried to contact you but haven't received a response.
6.6L Duramax L5P Cold Air Intake | 2017-2026 Sierra/ Silverado
Truck has a nice rumble but not excessively load like a straight pipe.
Muffler has great sound, no restrictions. The best part of the whole deal was the outstanding service and shipping that Tuner Depot provided. Would definitely use them again.
Fit was very good and looks great on my vehicle.
6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2025
Sound is exactly what I was looking for.
Was a little nervous if it was going to show up, nice quality and ease of install would purchase again
GM Duramax 6.6L - Shibby Engineering Tuner Harness Plug Kit (2011-2023)
Excellent
Nice mellow tone and quiet, no diesel is quiet but this muffler makes trips comfortable with no throwing noise at highway speeds.
Glad there are still parts company around
L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
Timely shipping Not yet installed
When buying the delete kit make sure you buy this if your doing a FULL delete. Once installed the truck sounded amazing with the 5 inch exhaust.
L5P Downpipe 3.5 Inch Turbo Direct Pipe | 2017-2026 GMC Chevrolet
Easier install then I expected solid switch cant complain
Really Love The Quality of the Exhaust look Great
L5P 5-Inch Stainless Steel Downpipe-Back Exhaust System | 2017–2025 Duramax 6.6L
Already put On All good Works Great
I Will Be Putting it all together this weekend But Love It
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