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

For 2015.5–2016 GM Duramax LML 2500/3500 – Unlock True Diesel Performance

 Take Your LML to the Next Level

Give your 2015.5–2016 GM Duramax LML 6.6L the performance upgrade it deserves. This downpipe-back race exhaust system is engineered to maximize airflow, boost horsepower & torque, improve fuel economy, and unleash an aggressive diesel sound that turns heads everywhere you go.

📦 What’s Inside the Box

• Heavy-duty SS409 stainless steel downpipe-back race exhaust
• 1.25″ wide band clamps – tight, leak-free seal
• Mandrel-bent tubing – smooth, unrestricted exhaust flow
• Pre-bent hangers – perfect alignment with factory mounts
• Straight pipe & muffler option included – choose your sound on install
• +1″ larger SS304 polished tip – bold, aggressive look
• Designed to reuse factory 3-bolt hardware

🚘 Vehicle Fitment

• 2015.5 & 2016 GM Duramax 2500/3500 (6.6L Diesel)
• Fits: Regular Cab (short & long bed), Crew Cab (short & long bed)
  ⚠️ Does not fit: Cab & Chassis commercial trucks (3-bolt flange only).

🛠 Built Tough – Built to Last

• Crafted from T-409 stainless steel for strength, corrosion resistance & long life
• Unlike T-304 stainless, T-409 is magnetic – don’t mistake it for lesser metals
• Perfect for winter driving in salted roads or heavy towing conditions

⚡ Performance Benefits

• Improved MPG – Gain up to 18–19 MPG combined after DPF/CAT delete (results vary with driving style & tires)
• More Horsepower & Torque – Eliminate restrictions, unleash the power of your LML
• Aggressive Exhaust Note – Deep, throaty sound without drone
• Cooler EGTs – Reduced exhaust backpressure keeps your engine running efficiently under heavy loads

    Installation Made Easy

• Install time: ~1 hour with basic hand tools
• Faster on a lift
• Cutting may be required on short wheelbase setups
• All clamps, hangers & hardware included (some factory hardware reused)

⚠️ Race Tuning Required

Special tuning is mandatory to avoid check engine lights and ensure proper performance.
✅ Recommended: EZ Lynk Tuning (see our tuning solutions for more options).

✅ Why This Exhaust?

• Designed specifically for the 2015.5–2016 Duramax LML
• Available in 4″ & 5″ diameters
• Bolt-on fitment with minimal modifications
• Boosts power, efficiency, and diesel sound instantly
• Built from durable stainless steel to withstand years of use

👉 Upgrade your LML today and experience raw diesel performance, unmatched sound, and better fuel efficiency with a system built for serious Duramax owners.