{"product_id":"3-5-downpipe-exhaust-for-2017-2026-l5p-6-6l-duramax-diesel","title":"3.5\" Downpipe Exhaust for 2017-2026 L5P 6.6L Duramax Diesel","description":"\u003cp\u003e---tab Description---\u003c\/p\u003e\n\u003ch2\u003eSPEtuner 3.5\" Turbo Downpipe Exhaust For 2017-2026 GM Chevy GMC 6.6L Duramax L5P\u003c\/h2\u003e\n\u003cp\u003eThis 3.5\" Turbo Downpipe for 2017–2023 Chevy\/GMC 2500HD\/3500HD 6.6L Duramax L5P. This catless high-flow pipe replaces restrictive factory bottlenecks, cutting backpressure and EGTs for instant turbo spool, max power, and sharp throttle response. Off-road\/race only; ECU tuning required.\u003c\/p\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb data-path-to-node=\"6,0,0\" data-index-in-node=\"0\"\u003eMassive High-Flow Exhaust Velocity:\u003c\/b\u003e Replaces the restrictive factory turbo-outlet pipe with a smooth, continuous 3.5-inch diameter mandrel-bent path to eliminate turbo-outlet backpressure and lag.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb data-path-to-node=\"6,1,0\" data-index-in-node=\"0\"\u003eDrastically Drops EGTs (Exhaust Gas Temps):\u003c\/b\u003e Eliminating factory thermal bottlenecks allows hot exhaust gases to evacuate instantly from the turbocharger, safeguarding your engine under sustained heavy towing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb data-path-to-node=\"6,2,0\" data-index-in-node=\"0\"\u003eInstantaneous Turbo Spool \u0026amp; Response:\u003c\/b\u003e Removing the factory restriction lets your turbocharger spin up with significantly less effort, giving you immediate throttle response across the RPM range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb data-path-to-node=\"6,3,0\" data-index-in-node=\"0\"\u003eAdvanced Thermal \u0026amp; Corrosion Defense:\u003c\/b\u003e Fabricated from thick, heavy-duty stainless steel and available in high-temp ceramic black or polished finishes to withstand extreme under-hood heat and road salt.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb data-path-to-node=\"6,4,0\" data-index-in-node=\"0\"\u003eIntegrated O2 Sensor Provisions:\u003c\/b\u003e Features factory-matched sensor bungs and robust 4-bolt turbo-outlet and V-band flanges for a secure, leak-free layout.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecification\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Stainless Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePipe Diameter:\u003c\/strong\u003e 3.5 inch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSurface:\u003c\/strong\u003e Mirror Polish\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConfiguration:\u003c\/strong\u003e Catless\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlange Type:\u003c\/strong\u003e \u003cspan\u003eBolt-on (4-Bolt) turbo outlet \u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e \u003cspan\u003e4.10\u003c\/span\u003e kg\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhat's Included in the Package?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHigh-Flow 3.5\" Catless Turbo Downpipe (Precision mandrel-bent stainless steel tubing)\u003c\/li\u003e\n\u003cli\u003eOEM-Matched Gaskets\u003c\/li\u003e\n\u003cli\u003eIntegrated Sensor Bungs \u0026amp; Heavy-Duty Hardware Set\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation\u003c\/h3\u003e\n\u003cp\u003eThe matching variant is designed as a direct bolt-on replacement for the listed factory turbo connection. Most installations can be completed with common hand tools in approximately 1–2 hours, although corrosion, access and model-specific heat shields can increase labor time. Have new gaskets and mounting hardware ready, use a 22 mm slotted O2 sensor socket where sensors are present, and apply penetrating oil to existing fasteners before removal. Use the vehicle manufacturer’s service information for disassembly procedures and torque specifications.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAllow the exhaust system to cool completely before work begins.\u003c\/li\u003e\n\u003cli\u003eCheck the mating surfaces and any reused clamp or seal for damage.\u003c\/li\u003e\n\u003cli\u003eConfirm clearance from wiring, hoses, heat shields, the firewall, transmission components and the chassis through the full routed section.\u003c\/li\u003e\n\u003cli\u003eAfter installation, inspect every joint for exhaust leakage, contact or movement.\u003c\/li\u003e\n\u003cli\u003eRecheck accessible connections after an appropriate heat cycle and investigate any exhaust smell, soot trace, rattle or diagnostic code.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e---tab Fitment---\u003c\/p\u003e\n\u003ch3\u003eFitment\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e2017 – 2026 Chevrolet Silverado 2500HD \/ 3500HD (6.6L V8 Duramax L5P Diesel)\u003c\/li\u003e\n\u003cli\u003e2017 – 2026 GMC Sierra 2500HD \/ 3500HD (6.6L V8 Duramax L5P Diesel)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e---tab FAQ---\u003c\/p\u003e\n\u003ch2\u003eFAQ\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ1: Does installing this 3.5\" downpipe on an L5P Duramax require custom tuning or cause a Check Engine Light (CEL)?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA1:\u003c\/strong\u003e No. The downpipe is located upstream of the primary emissions system (DPF\/SCR) and sensor bungs. Replacing only the factory downpipe on an L5P will not trigger a Check Engine Light or require custom tuning on an otherwise stock truck.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ2: How difficult is the removal of the factory L5P downpipe compared to older Duramax models?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA2:\u003c\/strong\u003e The L5P engine bay is packed extremely tight near the firewall. Removing the bulky, heavily heat-shielded factory downpipe requires unbolting the transmission dipstick bracket, releasing surrounding heat shields, and carefully maneuvering the pipe through the wheel well or cutting the OEM pipe into two pieces with a reciprocating saw for faster extraction.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ3: What do I do with the factory thermal heat blanket on the L5P turbo outlet?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA3:\u003c\/strong\u003e The 2017+ L5P utilizes specialized multi-layer factory heat blankets around the turbo housing and upper downpipe section. You should carefully unbolt and retain these heat blankets to reinstall them around the top section of the new 3.5\" downpipe to protect firewall insulation and wiring harnesses from excessive radiant heat.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ4: Will a 3.5\" diameter downpipe cause rubbing against the transmission housing or steering shaft?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA4:\u003c\/strong\u003e No. Although 3.5\" is larger than the crushed factory pipe, this downpipe is mandrel-bent specifically to navigate the narrow channel between the L5P block, transmission bellhousing, and passenger-side firewall. Maintaining good engine mount condition ensures at least 1\/2\" of air gap all around.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ5: Will this 3.5\" downpipe bolt directly to my stock front pipe and DPF assembly?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA5:\u003c\/strong\u003e Yes. The lower connection features a factory-style 2-bolt flange that mounts directly to the OEM front pipe and DPF flange, as well as any aftermarket 4\" or 5\" front-pipe\/delete pipe setup.\u003c\/p\u003e\n\u003cp\u003e---tab Shipping \u0026amp; Returns---\u003c\/p\u003e\n\u003ch2\u003eShipping \u0026amp; Returns\u003c\/h2\u003e\n\u003ch3\u003eFast Shipping Policy\u003c\/h3\u003e\n\u003cp\u003eYour order will be dispatched within \u003cstrong\u003e1-2 business days\u003c\/strong\u003e, and the package is expected to arrive by the estimated delivery date. \u003ca href=\"https:\/\/spetuner.com\/pages\/shipping-policy\" rel=\"noopener\" title=\"SPEtuner shipping policy\" target=\"_blank\"\u003eClick to View Shipping Policy.\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eEasy Return Policy\u003c\/h3\u003e\n\u003cp\u003eEvery order comes with a \u003cstrong\u003e30-day free return\u003c\/strong\u003e, which means you don't have to pay for a return slip. \u003ca href=\"https:\/\/dpfexhaust.com\/pages\/refund-policy\" rel=\"noopener\" target=\"_blank\"\u003eClick \u003c\/a\u003e\u003ca href=\"https:\/\/spetuner.com\/pages\/refund-policy\" rel=\"noopener\" title=\"SPEtuner refund policy\" target=\"_blank\"\u003eto View\u003c\/a\u003e\u003ca href=\"https:\/\/dpfexhaust.com\/pages\/refund-policy\" rel=\"noopener\" target=\"_blank\"\u003e Return Policy.\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003ePlease note that tuner units are final‑sale and cannot be returned or exchanged after purchase\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"SPEtuner","offers":[{"title":"Silver","offer_id":48552594047113,"sku":"#10489","price":219.0,"currency_code":"USD","in_stock":true},{"title":"Black","offer_id":48552594079881,"sku":"#10488","price":228.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0661\/3342\/6313\/files\/17_durmaaxdownpipe.webp?v=1791451332","url":"https:\/\/spetuner.com\/products\/3-5-downpipe-exhaust-for-2017-2026-l5p-6-6l-duramax-diesel","provider":"SPEtuner","version":"1.0","type":"link"}