Product Description
Open up your LB7 Duramax with the MBRP GM8425 3" Turbo Down Pipe (Armor BLK). This mandrel-bent, black-coated aluminized steel downpipe replaces the restrictive factory unit to improve turbo spool, reduce EGTs, and sharpen throttle response. Bolt-on install with factory-style connections.
Fitment
- 2001–early 2004 Chevrolet Silverado 2500HD/3500HD — 6.6L Duramax LB7
- 2001–early 2004 GMC Sierra 2500HD/3500HD — 6.6L Duramax LB7
- Excludes 2004.5 LLY (mid-year change)
Cross-Reference / MBRP Alternatives
- CARB-compliant version: MBRP GMCA425 3" Turbo Down Pipe (EO D-763-2)
- Pair with a downpipe-back system for maximum gains:
UPC / Identifiers
- UPC (GTIN-12): 882663111664
- GTIN-14 (EAN-14 format): 00882663111664
- MBRP Part #: GM8425 (Armor BLK)
Specifications
| Series | Armor BLK (black-coated) |
|---|---|
| Material | Aluminized steel, high-temp black coating |
| Tubing Diameter | 3.0 in (76 mm) |
| Construction | Mandrel-bent, bolt-on |
| Vehicle Configuration | 6.6L Duramax LB7 only (2001–early 2004) |
| Emissions | Not legal for sale/use in CA (use GMCA425 instead) |
| Warranty | MBRP limited warranty per series |
FAQ
Will this downpipe fit my 2004 LLY?No. This downpipe is for LB7 engines (2001–early 2004). For California or LLY applications, see the CARB-approved alternative linked above.
Do I need tuning after installation?
No tuning is required. It’s a direct bolt-on upgrade designed to improve flow and turbo response with factory calibration.
What should I pair this with for best results?
Combine it with an MBRP 4" downpipe-back system like S6005PLM or S6005P (both linked above) to maximize airflow and lower EGTs.
Is this legal in California?
The GM8425 Armor BLK is not for sale/use in California. Choose the CARB-compliant GMCA425 with EO D-763-2.
What’s included?
3" downpipe assembly with required connections. Reuse OE hardware and gaskets where applicable.
