4"/5" 2015.5-2016.5 LML 6.6 Duramax Turbo Back Exhaust Chevy GMC

4” / 5” Turbo-Back Exhaust System

2015.5–2016.5 Duramax 6.6L LML (Chevy / GMC)

*Race and off-road use only*

Upgrade exhaust flow and performance on your 2015.5–2016.5 LML Duramax with this 4” or 5” turbo-back exhaust system, manufactured by SPELAB and independently retailed by Secret Diesel Performance.

This turbo-back system replaces the factory exhaust from the turbo outlet to the rear exit, helping reduce backpressure and improve overall exhaust efficiency. Designed for off-road, competition, and performance-focused builds, it delivers a deeper, more aggressive exhaust tone while supporting future power upgrades.

Constructed from durable T-409 stainless steel, this system is built to handle high exhaust temperatures and demanding use. The modular design allows for proper fitment and straightforward installation for dedicated performance applications.

Features & Benefits

• Turbo-back exhaust system for 6.6L Duramax LML
• Available in 4” or 5” diameter configurations
• Improves exhaust flow and reduces backpressure
• Aggressive exhaust tone compared to stock
• Constructed from T-409 stainless steel
• Designed for race and off-road performance use

Fitment

• 2015.5–2016.5 Chevrolet Silverado 2500HD / 3500HD
• 2015.5–2016.5 GMC Sierra 2500HD / 3500HD
• 6.6L Duramax LML

Important Notes

• Intended for race and off-road use only
• Not legal for use on public roads in the United States
• Installation may require removal or modification of factory emissions components
• Professional installation recommended
• Product is independently retailed and not affiliated with or endorsed by the vehicle manufacturer