4.8 V-8 vs. 5.3 V-8 Engineby Rob Wagner
The General Motors 4.8- and 5.3-liter V-8 engines debuted in 1999 to power GM’s truck lineup. There were a handful of different 4.8-liter versions and numerous variants of the 5.3-liter engine. The primary difference between the two is that the 5.3-liter has a longer stroke, which adds more torque for better off-the-line acceleration and pulling power.
An early version of the 4.8-liter Vortec 4800 V-8 was the LR4, which powered the 1999 and 2002 to 2006 Chevrolet Silverado and GMC Sierra 1500 series half-ton trucks. The sport utility vehicles Chevy Tahoe and GMC Yukon also received the LR4. The LY2 version, which is the generation IV of the small block GM engines, differed from the LR4 with no variable valve timing or an active fuel management system. The LY2 powered 2007 and later Silverados, Sierras, Tahoes and Yukons.
The 5.3-liter Vortec 5300 came in LM7 standard fuel version, the L59 flexible fuel, and the LM4 and L33 variants. These larger engines also powered GM’s trucks and SUVs, and had a 9 mm longer stroke than the 4.8. The 2002 to 2005 Cadillac Escalade SUV, 2002 to 2005 Chevy Avalanche luxury truck, 2003 to 2007 Chevy Express and GMC Savana minivans, 2002 to 2006 Chevy Suburban and GMC Yukon XL, the Tahoe, Yukon and Sierra received the LM7. Buyers could also order the L59 for the Silverado, Tahoe, Yukon, Suburban and Sierra. The lightweight LM4 was available in the Chevy TrailBlazer, Isuzu Ascender, GMC Enjoy XL, Chevy SSR and Buick Rainier between 2003 and 2004. The L33 was a high-output version for the truck line. In 2005, the Generation IV Vortec 5300 arrived with the active fuel management LH6, flexible-fuel LMG, standard LY5, four-wheel-drive flexible-fuel LC9 and the LH8 to specially fit in Hummers.
Although smaller in displacement than the 5.3, the 4.8 developed enough horsepower for excellent towing capability and offered better fuel efficiency than in-line six-cylinders and some V-6 engines. A key attraction was its ability to operate at reduced vibration and noise levels. The engine displaced 293 cubic inches, or 4,807 cc, and had a compression ratio of 9.1-to-1. It had a 3.78-inch bore and 3.27-inch stroke. The LR4 generated between 270 and 290 horsepower and between 285 and 305 foot-pounds of torque depending on the model year and vehicle. The LY2 generated between 295 and 325 horsepower and 305 foot-pounds of torque.
GM increased the displacement of the 4.8 to 5.3 to accommodate the longer 3.6-inch stroke. The bore remained identical to the 4.8. General Motors considers the Generation IV Vortec 5300 5.3 the most significant small block engine since small-block V-8s arrived in 1955. The LM7 had a cast-iron block like the 4.3, but the L33 5.3 featured an aluminum block and cranked out 310 horsepower, about 15 horsepower more than the LM7. The LH6 also had an aluminum block. Overall, the standard 5.3 and its variants had a 9.1.-to-1 compression ratio. Horsepower ranged from 213 to 326 depending on the type of vehicle. Torque ranged from 335 to 350 foot-pounds.
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