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The Magnuson Supercharger Kit for the Jeep Grand Cherokee SRT represents one of the most compelling forced induction upgrades available for the 6.4L HEMI V8. This Roots-type supercharger system delivers a verified 100+ horsepower gain and costs approximately $6,500. For enthusiasts seeking a dramatic increase in acceleration and overall performance without sacrificing daily drivability, this kit offers a well-engineered solution that maintains factory reliability when properly installed and tuned.
Magnuson Supercharger Kit: System Overview
Magnuson Products, a leading manufacturer of supercharger systems based in California, developed the Maggie kit specifically for the 2012–2021 Jeep Grand Cherokee SRT with the 6.4L HEMI engine (also compatible with Dodge Durango SRT and certain Ram models). The kit uses a Eaton TVS R1320 positive displacement supercharger, known for its low heat generation, quiet operation, and excellent low-rpm boost response.
Key Components Included
- Eaton TVS R1320 supercharger unit – Twin Vortices Series rotor assembly with 1320cc displacement
- Cast aluminum intake manifold with integrated air-to-water intercooler
- Billet aluminum supercharger pulley (sized for approximately 6–7 psi boost)
- High-flow fuel injectors (upgraded 65 lb/hr or equivalent)
- Dual intercooler heat exchanger with electric water pump
- All necessary hoses, clamps, gaskets, and hardware
- Custom ECU calibration (via DiabloSport handheld tuner)
- Installation instructions and technical support
The system is designed as a complete bolt-on solution. The intercooler resides inside the intake manifold, reducing intake air temperatures while maintaining a compact underhood footprint. The supercharger mounts directly above the engine valley, replacing the factory intake manifold. No cutting, welding, or permanent modifications are required for installation.
Power Gains and Performance Metrics
Magnuson advertises a gain of over 100 horsepower at the crank. Real-world dyno results from independent shops show wheel horsepower increases between 90 and 110 hp, translating to roughly 480–500 whp on a stock Grand Cherokee SRT (versus 370–390 whp stock). Torque improvements are equally impressive, with peak torque rising by 80–100 lb-ft and a substantially fatter torque curve available from 2500 rpm onward.
0–60 mph and Quarter Mile Times
- Stock Grand Cherokee SRT: 0–60 mph in approximately 4.4 seconds, quarter-mile ~12.8 seconds
- Magnuson supercharged SRT: 0–60 mph in approximately 3.6–3.8 seconds, quarter-mile ~11.6–11.8 seconds
These gains significantly close the gap with high-performance SUVs like the Dodge Durango Hellcat and Porsche Cayenne Turbo. The supercharger provides immediate throttle response, eliminating the lag typical of centrifugal or turbocharger systems.
Drivability Characteristics
The Magnuson kit retains factory-grade drivability. Cold starts, idle quality, and part-throttle operation remain smooth. The air-to-water intercooler effectively manages charge air temperatures, preventing heat soak during aggressive driving. The supercharger produces a distinct but subdued whine under load, which many enthusiasts find satisfying without being intrusive during highway cruising.
Installation Process and Considerations
Installation of the Magnuson Supercharger Kit is rated as moderate to advanced by DIY standards. Magnuson estimates approximately 8–12 hours for experienced mechanics. The kit includes detailed printed instructions and step-by-step videos. Professional installation is recommended, particularly for the tuning and fuel system modifications.
Step-by-Step Installation Outline
- Disconnect the battery and drain the cooling system.
- Remove the factory intake manifold, throttle body, and associated components.
- Remove the factory fuel injectors (replace with provided high-flow units).
- Install the intercooler heat exchanger and circulate pump (front bumper area).
- Mount the supercharger unit and new intake manifold assembly.
- Connect coolant hoses, vacuum lines, and electrical connectors.
- Install the supercharger belt and tensioner.
- Reassemble the intake tract, throttle body, and air filter assembly.
- Load the provided calibration file via DiabloSport tuner.
- Prime the cooling system, check for leaks, and perform test drives.
Important Pre-Installation Checks
- Fuel system: Stock SRT fuel pumps typically support the 100 hp gain, but if you plan future upgrades (cams, larger pulley), a higher flow fuel pump is advisable.
- Ignition system: Replace spark plugs with colder heat range iridium plugs (NGK or equivalent) gapped to 0.035 inches.
- Cooling system: Ensure the coolant is fresh and the radiator is in good condition. Some owners upgrade to a higher-capacity radiator for track use.
- Transmission: The 8HP70 ZF eight-speed transmission handles the extra torque well, but fluid health should be checked.
Tuning and Calibration
The Magnuson kit ships with a DiabloSport i3 handheld tuner containing a custom calibration developed by Magnuson’s engineers. This calibration accounts for increased airflow and fuel requirements, optimizes timing, and adapts the electronic throttle for responsive drivability. The tuner also allows data logging for diagnostics and performance monitoring.
While the provided tune is safe and effective, many owners opt for a custom dyno tune from a reputable shop (such as Hemi Fever or Livernois Motorsports) to maximize gains. Custom tuning can yield an additional 10–20 horsepower by leaning out the air/fuel ratio and advancing timing on high-quality fuel (93 octane or E85).
It is essential to run the correct octane fuel. Magnuson recommends 91 octane minimum, 93 preferred. Using lower octane can cause detonation and engine damage. For sustained track use, an auxiliary fuel system or water-methanol injection may be beneficial.
Cost Analysis and Value Proposition
The Magnuson Supercharger Kit retails for approximately $6,500. This price includes all hardware, the supercharger unit, fuel injectors, intercooler, tuning device, and calibration. Additional costs may include professional installation ($800–$1,200), a custom dyno tune ($400–$800), and optional supporting modifications (colder spark plugs, catch can, upgraded radiator).
Comparison to Alternative Forced Induction Systems
| System | Type | Price Range | HP Gain | Drivability |
|---|---|---|---|---|
| Magnuson TVS R1320 | Roots (positive displacement) | $6,500 | 100+ | Excellent |
| ProCharger C4000 | Centrifugal | $5,800–$6,200 | 100–120 | Good (some lag) |
| RIPP Supercharger | Twin-screw | $5,500 | 90–110 | Very good |
| Whipple 2.9L | Roots (larger capacity) | $7,200 | 120+ | Excellent |
The Magnuson kit strikes a strong balance between price, power output, and drivability. The Eaton TVS design is known for its reliability and is used by many OEMs (including GM on the Corvette ZR1). For most SRT owners, the $6,500 investment provides the best combination of low-end torque and ease of installation.
Long-Term Reliability and Maintenance
Properly installed and tuned, the Magnuson supercharger adds minimal strain to the 6.4L HEMI engine. The engine’s forged internals (pistons and connecting rods) handle the extra 6–7 psi boost well. Key longevity considerations include:
- Oil changes: Use high-quality synthetic 5W-20 or 5W-30 and reduce intervals to 3,000–4,000 miles.
- Intercooler coolant: Replace annually to prevent corrosion.
- Supercharger oil: The Eaton TVS uses sealed bearings; no maintenance required for the supercharger itself for 100,000+ miles.
- Belt tension: Inspect the supercharger belt every 10,000 miles.
- Heat management: Consider a hood with heat extractors if living in hot climates or frequent track use.
Magnuson offers a 12-month/12,000-mile warranty on the supercharger unit. Engine damage caused by improper installation or tuning is not covered, which underscores the importance of professional calibration.
Testimonials and Community Reception
Owners on forums like Jeep Garage and Hellcat.org consistently praise the Magnuson kit for its seamless integration and dramatic performance uplift. Common feedback highlights the immediate throttle response and the fact that the vehicle remains a comfortable daily driver. Some users note that the full potential requires a custom tune and that the provided calibration is conservative by design.
The supercharger kit also opens the door for future upgrades. With a smaller pulley, added fuel system capacity, and E85 conversion, owners have reached 650+ crank horsepower on the stock engine bottom end, though supporting modifications become necessary at that level.
Conclusion
The Magnuson Supercharger Kit for the Jeep Grand Cherokee SRT delivers exactly what it promises: a reliable 100+ horsepower increase for approximately $6,500. The kit is thoughtfully engineered, includes all necessary components, and retains the vehicle’s everyday usability. For SRT owners who want a transformative performance upgrade without building an engine or sacrificing reliability, the Magnuson TVS R1320 supercharger kit stands as the premier bolt-on solution.
Whether you are hunting for a lower quarter-mile time, seeking the thrill of a supercharged engine surge, or simply want to dominate the on-ramp, this kit delivers. Invest in professional tuning, maintain your vehicle properly, and you will enjoy a Grand Cherokee SRT that performs like a true performance SUV.