The 6.6L Duramax LBZ was a short-lived generation of the Duramax 6600 introduced for the 2006 model year and retired mid-model year for 2007. It is mechanically identical to its predecessor, the 2006 model year LLY. The LBZ, however, was calibrated for higher horsepower and torque yields than the LLY, producing a peak 360 horsepower and 650 lb-ft of torque to the LLY's 310 horsepower and 605 lb-ft. The LBZ was the first Duramax diesel offered in the GMC Savana and Chevrolet Express 2500/3500 vans. A six speed manual transmission was offered alongside the Allison six speed automatic for the 2006 model year, while the manual transmission was retired for 2007 and the only available transmission in the Sierra/Silverado was the Allison 1000. Chevrolet Express and GMC Savana vans, which featured a significantly detuned version of the Duramax diesel, were only offered with a GM 4L85E 4 speed automatic.
The Duramax LBZ was ultimately phased out mid-model year in 2007 due to its inability to meet strict Federal emissions regulations. Its replacement, the LMM, featured an advanced exhaust aftertreatment system that included a soot-capturing diesel particulate filter. The LBZ became a popular choice for performance enthusiasts due to the engine's strengthened design, an abundance of aftermarket support, and its reasonably high factory performance.
6.6L LBZ Duramax Engine Specs
| Engine Family | 6.6L Duramax diesel (Duramax 6600) | |
| RPO Code | LBZ | |
| VIN Code | D (8th digit of VIN) | |
| Assembly Site | DMAX engine plant, Moraine, Ohio | |
| Applications/Production Years | 2006 - 2007 Chevrolet Silverado 2500 HD, 3500 HD 2006 - 2007 GMC Sierra 2500 HD, 3500 HD 2006 - 2007 Chevrolet Express 2500, 3500 2006 - 2007 GMC Savana 2500, 3500 2006 - 2007 Chevrolet Kodiak 2006 - 2007 GMC TopKick |
|
| Displacement | 6.599 liters (6.6 liters nominal), 402.62 CID (403 CID nominal) | |
| Configuration | 90 degree V-8 | |
| B10 Life | Not specified | |
| B50 Life | Not specified | |
| Bore | 4.055 inches (103.00 mm) | |
| Stroke | 3.897 inches (99.00 mm) | |
| Bore/Stroke Ratio | 1.04 (marginally oversquare) | |
| Compression Ratio | 16.8 : 1 | |
| Firing Order | 1-2-7-8-4-5-6-3 | |
| Cylinder Numbers |  Cylinders 1, 3, 5, and 7 are located on the passenger side bank Cylinders 2, 4, 6, and 8 are located on the driver side bank |
|
| Engine Block Material | Cast gray iron, induction hardened, deep skirt engine block | |
| Cylinder Head Material | Cast aluminum alloy | |
| Injection System | Direct injection Bosch high pressure common rail system Piezoelectric fuel injectors (7 hole) Bosch CP3 (CP3.3) injection pump 26,000 psi max injection pressure |
|
| Aspiration | Turbocharged, air-to-air intercooler Water-cooled Garrett GT3788VA variable vane turbocharger (VVT) |
|
| Minimum Cylinder Pressure | 300 psi (minimum compression test pressure) | |
| Reciprocating Assembly | Fracture split forged alloy steel connecting rods Nitrided forged steel crankshaft Forged steel camshaft Cast iron main bearing caps |
|
| Valvetrain | Overhead valve (OHV), standard cam-in-block, mechanical roller lifters 4 valves per cylinder (32 valve) |
|
| Cold Start Aid(s) | Traditional glow plug system, 1 per cylinder | |
| Engine Oil Capacity | 10 quarts with oil filter change | |
| Engine Oil Spec | See viscosity chart at 6.6L Duramax LBZ service guide | |
| Lube Oil Filter P/N | ACDelco PF2232 | |
| Fuel [1] | #2 low sulfur diesel fuel preferred (includes winterized blends) #1 low sulfur diesel fuel acceptable in cold weather Max B5 biodiesel blends (5% biodiesel, 95% petroleum diesel) |
|
| Horsepower | Sierra/Silverado | 360 hp @ 3,200 rpm |
| Express/Savana | 250 hp @ 2,500 rpm | |
| Kodiak/TopKick | 310 hp @ 3,000 rpm | |
| Torque | Sierra/Silverado | 650 lb-ft @ 1,600 rpm |
| Express/Savana | 460 lb-ft @ 1,600 rpm | |
| Kodiak/TopKick | 605 lb-ft @ 1,600 rpm | |
| Idle Speed | ~ 680 rpm @ operating temperature | |
| Governed Speed | 3,400 - 3,450 rpm (electronically governed) | |
| Emissions Equipment | Diesel oxidation catalyst (DOC), exhaust gas recirculation (EGR) | |
| Coupled Transmissions | Sierra/Silverado |
Allison 1000 6 speed automatic ZF S6-650 6 speed manual (2006 model year only) |
| Express/Savana | GM 4L85E 4 speed automatic | |
| Engine Weight | Approx. 835 lbs | |
| Engine Dimensions | Length | Approx 30.0 inches |
| Width | Approx 30.0 inches | |
| Height | Approx 32.0 inches | |
[1] - Ultra low sulfur diesel (ULSD) supersedes low sulfur diesel (LSD) specification in the United States, original OE recommendations listed.
6.6L LBZ Duramax Horsepower & Torque Curves
360 hp @ 3,200 rpm | 650 lb-ft @ 1,600 rpm
Editor, Diesel Hub