3.0" T4 Turbo Downpipe Exhaust for 1999-2013 Chevy Silverado & GMC Sierra 4.8/5.3/6.0/6.2L vortec LS

Flashark 3.0" T4 Turbo Downpipe Exhaust — 1999–2013 Chevy Silverado & GMC Sierra 4.8/5.3/6.0/6.2L Vortec LS V8

The Vortec LS V8 is one of the most turbo-friendly platforms on the market — but the factory exhaust manifold and downpipe routing were designed for naturally aspirated use. When you bolt a T4-flanged turbo onto an LQ4, LM7, or LY6, the stock exhaust path becomes the biggest restriction in your entire build. You need a purpose-built downpipe that flows from the turbine exit without crimps or bottlenecks.

This Flashark 3.0-inch (76 mm) T4 turbo downpipe is engineered specifically for single-turbo LS swap builds on 1999–2013 Silverado and Sierra trucks. It connects directly from the T4 turbine outlet flange to your mid-pipe or exhaust system with a free-flowing 3-inch mandrel-bent stainless steel pipe. The included 90° outlet tube and V-band clamp give you clean routing options within the engine bay, while the pre-welded O2 bung supports wideband sensor installation for tuning. A block-off plug is included if you don't need the bung.

This downpipe is designed for single turbo swap builds using a T4-flanged turbocharger. It is NOT compatible with stock naturally aspirated exhaust systems. For off-road and race use only — not street legal in California or emissions-controlled states.

Key Features

3.0" (76 mm) Mandrel-Bent Stainless Steel Tubing — Full 3-inch inner diameter from T4 turbine flange to outlet. Mandrel bends maintain consistent pipe diameter through every curve — no crush-bent restrictions, no turbulence pockets, no flow bottlenecks

T4 Turbo Flange — Direct Bolt-On — Precision-cut T4 flange mates directly to any T4-flanged turbocharger housing. No adapter rings, no fabrication — bolt the downpipe to your turbo and go

90° Outlet Tube Included — Flexible routing within the engine bay for tight LS swap clearances. The 90-degree bend allows the exhaust to clear frame rails, steering columns, and firewall on GMT800/GMT900 trucks

V-Band Clamp Included — Secure, leak-free connection at the outlet that won't rattle loose under boost. V-band clamps allow quick disassembly for turbo service without fighting rusted slip joints

Pre-Welded O2 Bung + Block-Off Plug — Wideband O2 sensor bung pre-welded at the correct depth for accurate readings. Stainless block-off plug included for builds that don't use a wideband — no welding or drilling required either way

Catless Design (Race-Off-Road) — Straight-through flow with no catalytic converter restriction. On a turbo LS, maximum exhaust flow after the turbine is critical for spool time and peak power — this pipe delivers unrestricted flow from flange to outlet

Mirror-Polished 201 Stainless Steel — Professional polished finish that resists the corrosive combination of exhaust condensate, road salt, and thermal cycling. Looks clean under the hood and holds up through multiple winters without surface rust

Complete Hardware Kit — Every gasket, bolt, and clamp required for installation is in the box. No trips to the hardware store, no guessing what size fasteners you need

Why Upgrade?

The factory exhaust manifold and routing on Vortec LS trucks were designed for NA use — they choke turbo flow, limit spool speed, and cap your power ceiling. This downpipe opens up the exhaust path from the T4 turbine exit, letting spent gases escape faster so your turbo builds boost earlier and your LT1/LS pushes harder through the entire RPM range.

Pro Tip: On a single-turbo LS build, the 3.0-inch downpipe diameter is well-matched for turbos in the 61mm–76mm inducer range (GT35R, GT40R, S366, S475). If you're running a larger turbo (S480+ or compound setup), consider stepping up to a 3.5" or 4" downpipe for optimal flow at high boost pressures.

Package Includes

• 1× 3.0" mirror-polished stainless steel T4 turbo downpipe
• 1× 90° outlet tube
• 1× V-band clamp
• 1× Pre-welded O2 sensor bung
  

This downpipe is designed for T4-flanged single turbo swap builds only. It does NOT include a turbocharger, exhaust manifold, mid-pipe, or cat-back exhaust. Professional installation recommended.