4″ / 5″ Downpipe-Back DPF & CAT Delete Exhaust System

For 2011–2015 GM Duramax LML 6.6L – Unlock Raw Diesel Power

🔥 Why Upgrade?

Transform your 2011–2015 GM Duramax LML 2500/3500 into the powerhouse it was meant to be. This downpipe-back race exhaust system is built to eliminate restrictive factory emissions components, increase horsepower & torque, improve fuel efficiency, lower EGTs, and deliver that aggressive diesel growl every Duramax owner loves.

Whether you’re towing heavy, daily driving, or racing, this system ensures your truck performs at its peak.

📦 What’s Included

• Heavy-duty SS409 stainless steel downpipe-back race exhaust
• 1.25″ wide band clamps for a tight, leak-proof seal
• Mandrel-bent tubing for smooth, unrestricted exhaust flow
• Pre-bent exhaust hangers for a direct bolt-on fit
• Straight pipe + muffler option included – choose your sound on install
• +1″ larger SS304 polished tip for a bold finish
• Reuses the factory V-band clamp (no guesswork required)

🚘 Vehicle Fitment

• 2011, 2012, 2013, 2014 & early 2015 GM Duramax LML 2500/3500 6.6L Diesel
• Fits: Regular Cab (short & long bed), Crew Cab (short & long bed)
  ⚠️ Not compatible with Cab & Chassis commercial trucks
  ⚠️ V-Band flange only – If your truck uses a 3-bolt flange, you have a 2015.5–2016 model (check before ordering).

🛠 Construction & Durability

• Made from T-409 stainless steel – built for strength, corrosion resistance, and long-lasting durability
• Note: Unlike T-304 stainless, T-409 is magnetic (a magnet will stick, but it’s still high-quality stainless)
• Highly recommended for trucks that see salted winter roads or heavy-duty use

⚡ Performance Benefits

• Boosted Horsepower & Torque – remove restrictions and free up raw diesel power
• Better Fuel Economy – Expect 18–19 MPG combined after DPF/CAT delete (driving habits & tires may affect results)
• Lower EGTs – optimized flow keeps your Duramax cooler under load
• Aggressive Exhaust Tone – deep, throaty diesel rumble without excessive drone

🔧 Installation

• Install time: ~1 hour with basic hand tools in your driveway
• Faster on a lift
• Cutting may be required on some cab/bed configurations
• Includes clamps, hangers, and hardware (reuse some factory components as needed)

⚠️ Race Tuning Required

This is a race-only exhaust system. Special tuning is required to prevent check engine lights and to maximize performance.
✅ Recommended: EZ Lynk Tuning (see our tuning section for more solutions).

✅ Why Choose This Exhaust?

• Precision-fit for 2011–2015 Duramax LML
• Available in 4″ & 5″ diameters
• Delivers more power, better efficiency & unbeatable diesel sound
• Built with premium stainless steel to handle tough conditions
• Designed for serious Duramax owners who demand performance

👉 Upgrade your Duramax today with a proven exhaust system that delivers sound, style, and serious power gains. Built to last – made to perform.