Best Exhaust For L5P Duramax

The L5P uses a 3.5 inch downpipe, smaller than owners coming from an older Duramax expect, and that changes which parts fit. EngineGo carries exhaust for L5P trucks from 2017 up in 4 inch and 5 inch downpipe-back layouts, plus the catless downpipe on its own. Note the year split in the listings, where 5 inch systems cover 2017-2019 and the 4 inch system covers 2020-2026, so your model year narrows the choice as much as your build does.

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2017-2019 Downpipe-Back Exhaust System DPF Delete 5" for Chevy/GMC 2500HD/3500HD 6.6L Duramax L5P | EngineGo

Downpipe-back Exhaust System DPF Delete 5" for 2017-2019 Chevy Silverado/GMC Sierra 2500HD/3500HD 6.6L Duramax L5P

Part #PDP0180AZZ

$679.25

Installation Difficulty Level: Moderate

Duramax Race Exhaust

Pipe Diameter: 5 Inch

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2017-2019 L5P 6.6L Duramax EGR/DPF/DOC Delete Kit 5" Downpipe-Back w/o Muffler, Downpipe | EngineGo

EGR/DPF/DOC Delete Kit for 2017-2019 L5P 6.6L Duramax | 5" Downpipe-Back without Muffler, EGR Delete, 3.5" Downpipe

Part #PCBDK0020AZZ

$1,019.01 $1,044.01

Installation Difficulty Level: Hard

Duramax All-in-one Kit

2017-2019 Downpipe-Back Exhaust System DPF Delete 4" for Chevy/GMC 2500HD/3500HD 6.6L Duramax L5P | EngineGo

Downpipe-back Exhaust System DPF Delete 4" for 2017-2019 Chevy Silverado/GMC Sierra 2500HD/3500HD 6.6L Duramax L5P

Part #PDP0290AZZ

$579.00

Installation Difficulty Level: Moderate

Duramax Race Exhaust

Pipe Diameter: 4 Inch

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2017-2019 6.6 Duramax L5P Downpipe-Back 4" & EGR Delete Kit Chevy Silverado/GMC Sierra 2500/3500HD

Downpipe-Back Exhaust DPF Delete 4" & EGR Delete Kit for 2017-2019 Chevy Silverado/GMC Sierra 2500/3500HD 6.6L Duramax L5P

Part #PCBDK01910AZZ

$721.77 $736.77

Installation Difficulty Level: Hard

Duramax All-in-one Kit

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2017-2019 L5P 6.6L Duramax EGR/DPF/DOC Delete Kit 4" Downpipe-Back w/o Muffler, Downpipe | EngineGo

EGR/DPF/DOC Delete Kit for 2017-2019 L5P 6.6L Duramax | 4" Downpipe-Back without Muffler, EGR Delete, 3.5" Downpipe

Part #PCBDK0030AZZ

$918.76 $943.76

Installation Difficulty Level: Hard

Duramax All-in-one Kit

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2017-2026 Chevrolet/GMC 6.6L Duramax L5P Downpipe Exhaust 3.5" for 2500HD/3500HD | EngineGo

3.5" Catless Downpipe for 2017-2026 Chevrolet Silverado/GMC Sierra 2500HD 3500HD 6.6L Duramax L5P

Part #POP0010AZZ

$218.99 $238.99

Installation Difficulty Level: Moderate

Duramax Downpipe

2020+ 6.6L Duramax L5P Downpipe-Back Exhaust System DPF Delete 4" for Chevy/GMC 2500HD/3500HD | EngineGo

Downpipe-back Exhaust System DPF Delete 4" for 2020-2026 Chevy Silverado/GMC Sierra 2500HD/3500HD 6.6L Duramax L5P

Part #PDP0300AZZ

$587.00

Installation Difficulty Level: Moderate

Duramax Race Exhaust

Pipe Diameter: 4 Inch

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2017-2019 6.6 Duramax L5P Downpipe-Back 5" & EGR Delete Kit Chevy Silverado/GMC Sierra 2500/3500HD

Downpipe-Back Exhaust DPF Delete 5" & EGR Delete Kit for 2017-2019 Chevy Silverado/GMC Sierra 2500/3500HD 6.6L Duramax L5P

Part #PCBDK01900AZZ

$822.02 $837.02

Installation Difficulty Level: Hard

Duramax All-in-one Kit

L5P Exhaust Systems

Sorted by year coverage and how much of the run you are replacing.

2017-2019 L5P, 5" downpipe-back without muffler, EGR delete, 3.5" downpipe: the full package including the downpipe and EGR work.
2017-2019 Silverado/Sierra, downpipe-back 5" with DPF and EGR delete: matched exhaust and delete hardware.
2017-2019 Silverado/Sierra, downpipe-back exhaust 5": the exhaust alone, no EGR hardware.
2020-2026 Silverado/Sierra, downpipe-back exhaust 4": the 4" run for later trucks.
2017-2026 Silverado/Sierra, 3.5" catless downpipe: the downpipe section on its own.

4 Inch, 5 Inch, and the 3.5 Inch Downpipe

The downpipe on an L5P is 3.5", and that is fixed by the turbo outlet, not a choice you make. What you choose is the diameter of the run behind it. A 4" system suits stock-turbo L5P trucks and keeps things sensible for towing. A 5" system makes sense on trucks making more power, though on a stock turbo the gain is mostly volume. Note the year split in the listings above, where the 5" systems are listed for 2017-2019 and the 4" system covers 2020-2026, so your model year narrows the choice as much as your build does. The catless downpipe is a separate item if you want to address that section without replacing the full run. L5P parts do not interchange with LML or LMM hardware.

Why L5P Owners Order From EngineGo

The 3.5" downpipe spec catches out owners who assume Duramax parts carry across generations. Every listing names the engine code, the year span, and every pipe diameter involved. Orders ship from U.S. warehouses, most process the same or next business day excluding Sundays, and free shipping applies within the continental United States. Authorized returns are accepted within 45 calendar days on qualifying items, and installed exhaust is generally not returnable. Send your year, model, cab style, bed length, and how the truck is built and support will confirm the right system.

Shop L5P Exhaust

Match your model year to the listed range first, since that narrows your diameter options, then decide how much of the run you are replacing. If you are on a stock turbo and torn between 4" and 5", message support and we will give you the practical answer rather than the bigger number.

Important: Some products in this collection are intended for off-road, race, or non-public-road use where permitted. Confirm federal, state, and local laws before purchase and installation. Customers are responsible for legal compliance.

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Best Exhaust For L5P Duramax

Downpipe-back Exhaust System DPF Delete 5" for 2017-2019 Chevy Silverado/GMC Sierra 2500HD/3500HD 6.6L Duramax L5P

EGR/DPF/DOC Delete Kit for 2017-2019 L5P 6.6L Duramax | 5" Downpipe-Back without Muffler, EGR Delete, 3.5" Downpipe

Downpipe-back Exhaust System DPF Delete 4" for 2017-2019 Chevy Silverado/GMC Sierra 2500HD/3500HD 6.6L Duramax L5P

Downpipe-Back Exhaust DPF Delete 4" & EGR Delete Kit for 2017-2019 Chevy Silverado/GMC Sierra 2500/3500HD 6.6L Duramax L5P

EGR/DPF/DOC Delete Kit for 2017-2019 L5P 6.6L Duramax | 4" Downpipe-Back without Muffler, EGR Delete, 3.5" Downpipe

3.5" Catless Downpipe for 2017-2026 Chevrolet Silverado/GMC Sierra 2500HD 3500HD 6.6L Duramax L5P

Downpipe-back Exhaust System DPF Delete 4" for 2020-2026 Chevy Silverado/GMC Sierra 2500HD/3500HD 6.6L Duramax L5P

Downpipe-Back Exhaust DPF Delete 5" & EGR Delete Kit for 2017-2019 Chevy Silverado/GMC Sierra 2500/3500HD 6.6L Duramax L5P

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