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Latest Powerplants Packing a Punch


The much-anticipated HEMI Hellcat engine is Dodge and SRT’s first application of V8 supercharger technology, delivering an amazing 600-plus horsepower.



This supercharged 6.2-liter HEMI V8 Hellcat engine is the most powerful V8 engine ever produced by the Chrysler Group.

According to Chrysler, its breakthrough supercharged engine ­features a forged-steel crankshaft with induction-hardened bearing surfaces.

The result is a crank so well-engineered it can withstand ­firing pressures of 110 bar (1,595 psi) – the equivalent of five family sedans standing on each piston, every two revolutions.

And its unique, specially tuned crank damper has been tested to 13,000 rpm.

High-strength, forged-alloy ­pistons – developed using advanced telemetry measurement – are coupled to powder-forged connecting rods with high-load-capacity bushings and diamond-like-carbon-coated ­piston pins.

The supercharged 6.2L HEMI (seen here) has premium-grade, heat-treated aluminum-alloy cylinder heads that are optimized for superior thermal conductivity. And, its die-cast aluminum rocker covers are painted HEMI Orange.


According to its engine designers, the blower used on the Hellcat is rated at 2,380 cc per rev, and spins at 14,600 rpm. The twin screw rotors have a special coating to reduce corrosion and to be conducive to higher tolerances and temperatures.

Air enters through a port near the driver’s side marker light and is redirected through an 8-liter air box before reaching the blower. Two air to water intercoolers, mounted on the supercharger housing, offer supplemental cooling.
An integrated electronic bypass valve regulates air boost, and a ­massive 92-mm throttle body ­controls the power. Fuel delivery is managed by half-inch fuel lines and 600 cc/min fuel injectors.


The Hellcat engine also uses a high-tech lubrication system employing a high-flow gerotor pump, oil-to-air heat exchanger and piston cooling jets.

The race for higher production horsepower using supercharged ­engines has gained momentum.

In early June, General Motors ­announced its Corvette Z06’s LT4 ­supercharged 6.2L V8 engine is SAE-certified at 650 horsepower at 6,400 rpm and 650 lb-ft of torque at 3,600 rpm.

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The new LT4 engine (seen here) is based on the same Gen 5 small block foundation as the Corvette Stingray’s LT1 6.2L naturally aspirated engine, incorporating several unique features designed to support its higher output and the greater cylinder pressures created by forced induction, including:

•Rotocast A356T6 ­aluminum cylinder heads that are stronger and handle heat better than conventional aluminum heads;

• Lightweight titanium intake valves;

• Machined, forged powder metal steel connecting rods for reduced reciprocating mass;

• A high 10.0:1 compression ratio – for a forced-induction engine;

• Forged aluminum pistons with unique, stronger structure to ensure strength under high cylinder ­pressures;

• Stainless steel exhaust manifolds and an aluminum balancer that are lighter than their LT1 counterparts,

• Standard dry-sump oiling ­system with a dual-pressure-control oil pump, and

• A new 1.7L supercharger that spins at up to 20,000 rpm – 5,000 rpm more than the supercharger on the Corvette ZR1’s engine.


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