General Motors recently announced its all-new 6.6L V8 L8T gasoline engine for the 2020 Chevrolet Silverado HD and 2020 GMC Sierra HD. This immediately made us wonder whether the new motor will make its way under the expansive hood of the new Chevy Silverado Medium Duty. Now, another good candidate comes to mind: the Chevrolet Suburban HD.
Unlike the regular Chevy Suburban, the Suburban 3500 HD is only available to fleet customers, and it’s all about payload, featuring a standard payload capacity of 4,405 pounds and a GVWR (gross vehicle weight rating) of 11,000 pounds. The maximum towing capacity, meanwhile, drops to 3,000 pounds from the regular Suburban’s 8,000-pound towing capacity.
Currently, the Suburban HD is powered exclusively by the 6.0L V8 Vortec L96 gasoline engine paired to GM’s 6L90 6-speed heavy-duty automatic transmission. Notably, the new L8T is the successor to the L96, which also serves as the base engine for the current, K2 platformed Chevy Silverado HD and GMC Sierra HD models, where it is rated at 360 horsepower and 380 pound-feet of torque.
Although capable, the L96 is a relic of an engine, having been around for roughly two decades. The most notable change it received was in the 2009 timeframe, when it got Variable Valve Timing (VVT). It even features Sequential Fuel Injection (SFI), rather than direct injection.
So, if the L8T engine comes to the Suburban HD, then it will likely be only for the next-gen model – which is expected for the 2020 model year (see more on 2020 Suburban). The Suburban HD is naturally a great candidate to get the new engine in addition to the Silverado Medium Duty models. Although we expect the twelfth-gen 2020 Suburban to launch in the fall of this year, it’s unclear whether it will also derive an HD variant this go-round.
About GM’s 6.6L V8 L8T Engine
Based on GM’s fifth-generation Small Block engine architecture, GM’s new 6.6L V-8 L8T gasoline engine is SAE-rated at 401 horsepower and 464 pound-feet of torque in the 2020 Silverado HD and 2020 Sierra HD.
It runs an iron block with aluminum heads, along with direct injection and variable valve timing at a 10.8:1 compression ratio. All that enables it to make robust power low on the power band, which is particularly helpful when it comes to towing.