The power rating of 6.4 HEMI varies on different applications that range from 470 – 525 HP with 470 – 510 lb-ft of torque available. It cuts out the valve lifters of the involved cylinders in order to eliminate pumping losses. This mechanism turns off fuel in four cylinders when power is not demanded. The truck engine is more efficient by integrating a cylinder deactivation system called Multi Displacement System or MDS. Valve-train consists of hydraulic roller lifters and sodium-filled exhaust valves. The 6.4 truck engine has a variable valve timing, cam-in-block, that uses a hydraulic cam phasing system developed by Chrysler. At the same time, the truck 6.4L HEMI has an active dual-runner-length intake manifold for low to mid-range engine speeds without compromising the higher-end power of SRT V8s.īoth the high-speed and truck version shares the drive-by-wire throttle bodies. The headcovers are made from plastic and a plastic intake manifold with shorter runners for high-speed SRT vehicles such as Challenger and Charger. These heads feature a larger cross-sectional head port area that provides a better airflow on both the intake and exhaust ports – 11% intake and 13% exhaust. The 6.4 HEMI cylinder heads are also identical to those of 5.7 HEMIs, which have two valves and two spark plugs in each cylinder, in addition to the oval-shaped, semi-hemispherical combustion chambers. This cooler not only makes the engine safe but also stretches the engine’s lifespan and longevity.įurthermore, the 6.4 HEMI has better connecting rods made of higher-strength powder material and larger diameter flat-top pistons with fully floating pins. And for this reason that Chrysler integrated an oil-to-water oil cooler to provide additional cooling under extreme conditions. These squirters spray engine oil underneath each piston to regulate combustion heat for better performance. The 6.4 HEMI engine also features piston cooling jets or squirters. These cross-bolted caps are cast into the ending block to increase the block’s rigidity, so everything stays intact to handle large amounts of energy, especially when maximizing engine power. While the aluminum heads and deep-skirt cast-iron block are used on the 3.6L Pentastar V6, the cross-bolted main bearing caps are designed for special performance modifications.

The cylinder block comprises deep-skirt cast-iron material with cross-bolted main bearing caps and aluminum alloy headers. Resulting in higher RPM range – and more power, without overplaying the piston speed. Oversquare engines mean that the cylinders have a greater bore than the stroke, making the bore/stroke ratio greater than 1. The 6.4L HEMI engine is an over-square engine with a 103.9 mm cylinder bore, 94.6 mm piston stroke, and 10.9 compression rating for most SRT vehicles.

The engine design revolved around the 90-degree cylinder bank orientation. The framework of the 6.4 L HEMI can also be found in the 6.1 and 5.7 L HEMI they are the same but have different bores and strokes. Compression Ratio: 10.9 for 6.4 L HEMI SRT and 10.0 for 6.4 HEMI RAM Trucks.Valvetrain: OHV, two valves per cylinder.In addition to that, Special-Edition Chargers as well as Challengers installed with this engine, and the machines themselves, will have the 392 HEMI badge in commemoration of the first-generation engine of the same displacement.Īn updated 2015 version of the 392 HEMI was released with a 485 horsepower output and 475 lb-ft of torque in the Challenger SRT 392, Charger, and R/T Scat Pack Models. The newly launched 392 HEMI is based on the third-generation 5.7 L HEMI, codenamed as “The Eagle,” while the 6.4 is codenamed as “Apache,” sharing few parts with the 392 HEMI crate engine. There are several improvements, including stronger forged aluminum-alloy pistons it is also more powerful and produces more torque deemed suitable for towing and hauling like its alternate turbocharged diesel version – the 6.7 L ISB Cummins.īut the production version came out in the form of the 2011 Dodge Challenger SRT 8 equipped with variable camshaft timing and MDS in vehicles with automatic transmissions. The engine has been available in the market since 2007 as a crate engine under the badge 392 HEMI.

What are Dodge HEMI 6.4 L Engines?Ĭhrysler created a wide range of HEMI engines, and they launched a more powerful and larger 392 cubic-inch HEMI in 2005 with a factory-rated output of 525 HP and 510 lb-ft of torque. In retrospect, the 392 HEMI can be found across Chrysler products in late 1950 before its re-emergence until 2011, carrying the same confidence they had over the years.īut apart from the respect of its competitive peers, what does the 392 HEMI have? Let’s have a brief tour of the 6.4 L HEMI engine. HEMI engines can be traced way back to the 1950s when Chrysler’s revolutionary hemispheric combustion chambers took over the automotive arena by having a more efficient and powerful engine.

Dodge variable valve timing