Description
Product Overview
Replace your restrictive factory downpipe with the iFJF 3-inch T304 Stainless Steel Turbo Downpipe — engineered for 2011–2015 Chevrolet/GMC 6.6L Duramax LML diesel trucks. This premium downpipe is the critical first section of your exhaust system, directly connecting to the turbocharger outlet and dictating how quickly exhaust gases can escape.
Constructed from 16-gauge T304 stainless steel with computerized mandrel bends, this downpipe eliminates the bottlenecks found in the factory exhaust and provides a solid foundation for your performance build. Includes a roll of titanium exhaust heat wrap for additional thermal management.
Key Features
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16-Gauge T304 Stainless Steel — Premium material, superior corrosion resistance vs. T409
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3.0" OD Mandrel-Bent Tubing — Smooth, unrestricted flow path
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CNC-Machined Flanges — Chrome plated for corrosion resistance, precision fit
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100% TIG Welded — All joints TIG welded for maximum strength and crack resistance
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Includes Titanium Heat Wrap — Reduces under-hood temperatures and turbo lag
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V-Band Style Connection — Direct bolt-on for 2011–2015 LML models
Vehicle Compatibility
| Year |
Make |
Model |
Engine |
| 2011–2015 |
Chevrolet |
Silverado 2500HD / 3500HD |
6.6L Turbo Diesel LML |
| 2011–2015 |
GMC |
Sierra 2500HD / 3500HD |
6.6L Turbo Diesel LML |
⚠️ V-Band Only! Fits 2011–2015 LML models with V-band clamp at the turbo. Does NOT fit 2015.5–2016 3-bolt flange models or Cab & Chassis trucks.
Performance Benefits
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+10–15 HP & 20–25 lb-ft Torque — Reduced restriction = more usable power
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Lower EGTs — 150–250°F drop under load
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Faster Turbo Spool — Less backpressure means quicker boost response
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Better Fuel Economy — Engine doesn't work as hard to push exhaust out
Package Includes
- 1 × 3" T304 Stainless Steel Downpipe
- 2 × Stainless Steel Hose Clamps
- 1 × Roll of Titanium Exhaust Heat Wrap
Frequently Asked Questions
Q: Will this downpipe bolt directly to my factory exhaust?
A: This downpipe is designed as a performance replacement and works best when paired with a 3" or 4" exhaust system. It connects to the turbo via V-band clamp and may require an adapter to connect to the factory cat-back.
Q: Do I need a tune after installing this downpipe?
A: A tune is recommended to fully optimize fuel and boost maps after reducing exhaust restriction, but the truck will run without one.
Q: Can I install this without welding?
A: Yes, this is designed as a bolt-on replacement using the factory-style V-band clamp connection at the turbo.
Q: What's the difference between T304 and T409 stainless?
A: T304 offers superior corrosion resistance and a brighter finish. T409 is more cost-effective and still magnetic. This downpipe uses T304 for maximum durability.
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