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GM 6.6 Liter V-8 L8T Engine
The L8T is a gasoline engine produced by General Motors for use in Heavy Duty pickup trucks. The engine displaces 6.6 liters in a V8 configuration and an OverHead Valve (OHV) layout otherwise referred to as push-rod.
It is part of GM’s fifth-generation Small Block engine family and made its debut in the all-new 2020 Chevrolet Silverado HD and 2020 GMC Sierra HD.
Overview
The 6.6L V8 L8T is built on a cast-iron Small Block, enabling it to have long-term durability. Thanks to aluminum heads and direct injection, the engine delivers more precise fuel control resulting in a higher compression ratio of 10.8:1. That enables a power output of 401 horsepower and 464 pound-feet of torque (in the 2020 Silverado HD and 2020 Sierra HD), with strong performance at low rpm, where it is needed when pulling away with a loaded cargo box or trailer.
The L8T also features a forged steel crankshaft, forged powder-metal connecting rods and additional high-strength components to provide the added strength and durability demanded by Heavy Duty truck customers.
The L8T replaces the 6.0L V8 L96 / LC8 engine and makes over 11 percent more horsepower and over 21 percent more torque.
Interestingly, the L8T does not use GM fuel saving technologies such as Active Fuel Management (AFM), Dynamic Fuel Management (DFM), or Auto Stop-Start (ASS).
Vehicle Applications
| Manufacturer | Model Year | Make | Model | Transmission | Power (hp / kW) @ RPM | Torque (lb-ft / Nm) @ RPM |
|---|---|---|---|---|---|---|
| General Motors Company | 2020 | Chevrolet | Silverado HD | 6-speed auto (6L90) | 401 / 299 @ 5200 (SAE certified) | 464 / 629 @ 4000 (SAE certified) |
| General Motors Company | 2020 | GMC | Sierra HD | 6-speed auto (6L90) | 401 / 299 @ 5200 (SAE certified) | 464 / 629 @ 4000 (SAE certified) |
Specifications
| GM RPO Code: | L8T |
|---|---|
| Type: | 6.6L V-8 gasoline |
| Bore & Stroke (in / mm): | 4.06 x 3.86 / 103.25 x 98 |
| Block Material: | Cast iron with nodular iron main caps |
| Cylinder Head Material: | Cast aluminum |
| Compression Ratio: | 10.8:1 |
| Valvetrain: | Overhead-valve, two valves per cylinder, variable valve timing |
| Fuel Delivery: | Direct fuel injection |
| Recommend Fuel: | 87 octane |
| Power (hp / kW @ rpm): | 401 / 299 @ 5200 (SAE certified) |
| Torque (lb.-ft. / Nm @ rpm): | 464 / 629 @ 4000 (SAE certified) |
| Predecessor: | 6.0L V8 L96/LC8 |
| Successor: | None currently |
Photos
Coming soon.
