How Much Boost Can A 6.1L HEMI Handle?

The 6.1L HEMI debuted shortly after the 5.7L HEMI returned to the Chrysler engine lineup. From the start, the 6.1 HEMI, developed by Chrysler's Street and Racing Technology (SRT) group, was designed with performance in mind. It ruled the Gen 3 HEMI lineup from its 2005 introduction with up to 425 horsepower and 420 foot-pounds of torque until the 6.1 HEMI was succeeded by the 6.4 HEMI in 2011.

While the 6.4 HEMI, with up to 485 horsepower and 475 lb-ft of torque, represented a substantial upgrade in power, it was no match for the 6.2L HEMI that came a few years later. The 6.2 HEMI in the 2015 Dodge Challenger SRT Hellcat produced 707 horsepower and 650 lb-ft of torque. Its secret was the addition of a supercharger.

Superchargers work by forcing air into the engine through its intake system. This forced air induction allows the introduction of more fuel without the risk of creating a mixture that is too rich with fuel to burn efficiently, producing more power from the same displacement. The good news is that companies like Magnuson Superchargers and Edelbrock offer bolt-on supercharger kits with prices listed at $6,495 and $9,572.87 respectively. However, you'll want to add $1,245 for Magnuson's Universal Cooling System, while the Edelbrock kit comes with an air-to-water intercooler. The Edelbrock kit advertises maximum boost pressures rated at 6 psi, which a 6.1 HEMI with stock internals should handle without issue when combined with enough fuel and a good tune.

Edelbrock claims its Stage 1 Supercharger Kit increases the stock 6.1L HEMI output to 556 horsepower and 520 lb-ft of torque, an increase of 131 hp and 100 lb-ft of torque. The Magnuson Superchargers' TVS2650 Supercharger System claims gains of 155 horsepower and 155 lb-ft of torque.

In 2018, MotorTrend bolted an Edelbrock E-Force TVS supercharger kit onto a 6.1 HEMI in a Chrysler 300C SRT8 they acquired for under $10,000. That kit supplied around six pounds of boost pressure, came with upgraded 46-pound-per-hour fuel injectors to match the increased airflow, and a 50-state-legal DIY tune. It also claimed to add around 135 horsepower, although dyno testing didn't support quite that much gain thanks to the car's clogged catalytic converter.

The 6.1 HEMI is capable of producing in excess of 1,000 horsepower with just over 20 pounds of boost supplied by a larger supercharger like the Kenne Bell 3.6L twin-screw unit, priced at $8,349. However, don't press the buy button on that kit just yet, as the stock internals of the 6.1 HEMI will not stand up to that much boost for very long.

If a 6.1 HEMI with four-digit horsepower is the goal, it'll need forged internals, including new pistons and connecting rods, at least. It'll also benefit from porting the cylinder heads, an appropriate camshaft, and upgraded exhaust to bring in the good stuff and export the bad stuff.