Product Description
MBRP GM8428 3" Turbo Down Pipe — Aluminized Steel
Unlock flow and lower EGTs on your LML with MBRP’s direct-fit 3" turbo down pipe. Built from rugged aluminized steel with smooth mandrel bends, GM8428 replaces the restrictive factory piece to improve response and overall drivability while retaining factory emissions equipment.
- Direct bolt-on for 2015–2016 6.6L Duramax LML (Silverado/Sierra 2500HD/3500HD)
- 3" mandrel-bent tubing for increased exhaust flow
- Aluminized steel construction
- DPF/SCR-compatible design (retains OEM aftertreatment)
- 3-bolt turbo outlet flange
Fitment
- 2015.5–2016 Chevrolet Silverado 2500HD/3500HD — 6.6L Duramax LML
- 2015.5–2016 GMC Sierra 2500HD/3500HD — 6.6L Duramax LML
- Turbo outlet: 3-bolt flange; designed to work with the OEM DPF/SCR system.
What’s Included
- (1) 3" aluminized steel down pipe assembly
- Installation instructions
- Hardware as supplied by MBRP (reuse select factory hardware as required)
Helpful Notes
- Not for sale in California for non-CARB configurations. If you need a CARB-EO option for 2011–2015 LML, see the alternative below.
- Professional installation recommended; allow penetrant on fasteners and verify clearance around heat shields.
Cross-Reference / Alternatives (MBRP-only)
- CARB-EO Alternative (2011–2015 LML): MBRP GMCA427 3" Turbo Down Pipe (CARB)
- Earlier LBs/LBZ/LMM Coverage: MBRP GM8425 3" Turbo Down Pipe (2001–2004)
Recommended MBRP Add-Ons
Why Buy from CPP Diesel
- Diesel specialists with fast shipping and phone support
- Price-match friendly and curated, model-specific fitment
FAQ
Does the GM8428 work with the factory DPF/DEF system?
Yes. This down pipe is designed to retain the OEM aftertreatment on 2015.5–2016 LML trucks.
Is tuning required after installing this down pipe?
No tuning is required for fitment; it’s a flow upgrade at the turbo outlet. Always verify local regulations.
Is there a California-legal option?
For 2011–2015 LML models that require a CARB-EO, use the MBRP GMCA427. The GM8428 is not for sale in CA.
What size is the turbo flange?
The GM8428 uses a 3-bolt turbo outlet flange specific to the LML turbo on 2015.5–2016 applications.
