6.6L Duramax LBZ

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.

6.6L LBZ Duramax Engine Specs, History, & Information

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 Specs

Engine Family:

6.6L Duramax diesel (Duramax 6600)

RPO Code:


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


6.599 liters (6.6 liters nominal), 402.62 CID (403 CID nominal)


90 degree V-8

B10 Life:

Not specified

B50 Life:

Not specified


4.055 inches (103.00 mm)


3.897 inches (99.00 mm)

Bore/Stroke Ratio:

1.04 (marginally oversquare)

Compression Ratio:

16.8 : 1

Firing Order:


Cylinder Numbers:

6.6 Duramax cylinder numbers and locations

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


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


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)

Peak Horsepower:


360 hp @ 3,200 rpm


250 hp @ 2,500 rpm


310 hp @ 3,000 rpm

Peak Torque:


650 lb-ft @ 1,600 rpm


460 lb-ft @ 1,600 rpm


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:


Allison 1000 6 speed automatic
ZF S6-650 6 speed manual (2006 model year only)


GM 4L85E 4 speed automatic

Engine Weight:

Approx. 835 lbs

Engine Dimensions:


Approx 30.0 inches


Approx 30.0 inches


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

6.6L Duramax LBZ horsepower and torque curves

6.6L Duramax LBZ horsepower and torque curves, GMC Sierra & Chevrolet Silverado Models
360 hp @ 3,200 rpm | 650 lb-ft @ 1,600 rpm