Understanding the Hellion TwinTurbo System

For Dodge Challenger owners seeking next-level performance, a forced induction upgrade often stands as the most transformative modification. Among the aftermarket options, the Hellion TwinTurbo System has earned a reputation for delivering exceptional power while maintaining drivability. This system is engineered specifically for late-model Challenger platforms, including the 5.7L HEMI, 6.4L HEMI, and the legendary 6.2L Hellcat V8. Rather than relying on a single large turbocharger, Hellion uses two smaller, precision-matched turbochargers. This twin-turbo configuration reduces turbo lag, provides quicker spool, and allows for a broader powerband. By forcing more air into the combustion chambers, the system enables the engine to burn more fuel efficiently, producing substantial gains in both horsepower and torque without sacrificing reliability when properly tuned.

The Hellion system is a complete kit, including all necessary plumbing, oil and coolant lines, intercoolers, blow-off valves, and wastegates. It is designed to integrate seamlessly with the Challenger’s factory engine management system, though aftermarket tuning is highly recommended to unlock its full potential. The twin-turbo setup also improves throttle response compared to a supercharger, making it a popular choice for drivers who want both street manners and track-ready power.

Power Gains from the Upgrade

When upgrading to the Hellion TwinTurbo System, the power increases are substantial and consistent across different engine variants. On a stock 6.4L HEMI, owners typically see rear-wheel horsepower gains of 200–300 HP and torque increases of 150–200 lb-ft, depending on boost levels and fuel quality. For the Hellcat engine, which already benefits from a supercharger, a Hellion twin-turbo conversion can push output well past 1,000 HP with proper supporting modifications and tuning.

These gains are not just peak numbers; the torque curve becomes much flatter and earlier, providing strong pull throughout the RPM range. The twin-turbo system also reduces parasitic loss compared to a belt-driven supercharger, meaning more of the power reaches the wheels. Many Challenger owners report a completely transformed driving experience after the upgrade, with effortless acceleration and the ability to dominate at the drag strip or on the open road.

Factors That Influence Power Gains

While the Hellion system offers impressive baseline increases, actual power output depends on several variables. Understanding these factors helps set realistic expectations and guides preparation for the upgrade.

  • Engine type and condition: A healthy, well-maintained HEMI will respond better to boost. Engines with high mileage or pre-existing issues should be inspected and refreshed before installation.
  • Boost level: The wastegates supplied with the kit can be adjusted. Increasing boost from a conservative 6–7 psi to 10–12 psi adds significant power but requires careful tuning and higher-octane fuel.
  • Fuel quality and delivery: Premium pump fuel (93 octane) is adequate for moderate boost, but E85 or race fuel may be needed for higher outputs. Upgrading fuel injectors, fuel pump, and lines becomes necessary as horsepower climbs.
  • Existing modifications: A Challenger already equipped with headers, a camshaft, or a built bottom end will realize higher gains from the twin-turbo system than a completely stock car.
  • Tuning quality: The calibration of the ECU is the single most critical factor in realizing safe, reliable power. A professional tuner experienced with turbocharged HEMI engines is essential.

Installation Insights

Installing the Hellion TwinTurbo System is a major undertaking that requires mechanical skill, proper tools, and a thorough understanding of turbocharging principles. The kit is engineered to be as “bolt-on” as possible for a twin-turbo setup, but it still involves significant disassembly of the engine bay, exhaust, and cooling systems. Hellion provides detailed instructions, but professional installation is strongly recommended unless the owner has extensive fabrication and automotive experience.

The entire installation typically takes 20–40 hours for an experienced technician. Planning ahead—gathering all tools, replacement hardware, and any ancillary upgrades—will prevent delays. It is also wise to set aside a budget for consumables like gaskets, fluids, and replacement fasteners.

Step-by-Step Installation Process

Below is a high-level overview of the installation sequence. Specific steps vary by model year and engine, but the general flow remains consistent.

  1. Disassembly and preparation: Remove the factory intake system, exhaust manifolds, and front bumper cover. Drain engine coolant and oil. Disconnect the battery and allow the engine to cool.
  2. Install turbocharger mounting brackets: Hellion supplies custom brackets that attach to the engine block and chassis. These position the turbos in the lower front corners of the engine bay, clear of other components.
  3. Mount turbochargers and wastegates: Secure the two GT-series turbochargers (Hellion uses various models depending on power goals) onto the brackets. Attach the wastegates and connect the boost reference lines.
  4. Route oil and coolant lines: Oil feed lines run from the engine to the turbos; drain lines route back to the oil pan. Coolant lines connect to the engine cooling system. Use only quality fittings and ensure no leaks.
  5. Install exhaust piping and downpipes: The kit includes mandrel-bent stainless steel downpipes that connect the turbo outlets to the factory exhaust or an aftermarket system. Clamps and gaskets must be tight.
  6. Mount intercoolers and intake plumbing: Hellion systems often use dual air-to-air intercoolers mounted behind the front fascia. Connect the charge pipes from the turbo outlets to the intercoolers and then to the throttle body. All couplers must be snug with T-bolt clamps.
  7. Install blow-off valve and intake filters: A blow-off valve (BOV) is included to protect the turbo system from pressure spikes. High-flow air filters are positioned in a cool, dry location.
  8. Reassemble and connect electronics: Reinstall the front bumper, reconnect the battery, and route any necessary wiring for boost controllers, gauges, or wideband oxygen sensors. Refill oil and coolant.
  9. Initial startup and inspection: Before starting the engine, prime the oil system by cranking with the fuel pump relay removed. Check for leaks, listen for unusual noises, and verify that wastegate actuators open correctly.

Common Installation Challenges

Even with a well-designed kit, some difficulties may arise. These include:

  • Clearance issues: On narrow engine bays like the Charger or Challenger, the power steering lines or AC lines may need slight repositioning.
  • Heat management: Twin turbos generate substantial heat. Heat wrap on downpipes, reflective shielding on nearby wiring and hoses, and proper air ducting are vital to avoid heat soak.
  • Oil drain routing: Ensuring a reliable gravity oil return to the pan can be tricky; some installations require a dedicated oil pan with a welded bung.
  • Intercooler fitment: Aftermarket front bumpers or tow hooks may interfere with the intercoolers. Trial fitting is recommended before final assembly.

Post-Installation Considerations

Once the system is installed, the next critical phase is tuning and validation. Without proper calibration, the twin-turbo setup can cause knock, lean conditions, or excessive boost, leading to engine damage. A reputable tuner with a dynamometer and experience in forced induction HEMI engines should handle this step. Expect spending several hours on the dyno to dial in the air/fuel ratio, ignition timing, and boost curve.

After tuning, regular maintenance becomes more intense. Oil changes should be performed every 3,000–5,000 miles using high-quality synthetic oil, as turbos place additional thermal and mechanical stress on the lubricant. Inspect the air filters, boost hoses, and clamps every oil change for cracks or looseness. It is also wise to install a boost gauge and wideband air/fuel ratio gauge to monitor system health in real time.

Drivability after the upgrade is generally excellent if the kit is well-tuned. Cold starts are normal, idle quality remains good, and there is minimal turbo lag thanks to the quick-spooling twins. On the other hand, the engine will produce more heat, so monitoring coolant and oil temperatures during spirited driving is essential. An auxiliary oil cooler or upgraded radiator may be worth considering for track use.

Long-Term Reliability

A properly installed and tuned Hellion TwinTurbo System can last many years and tens of thousands of miles without major issues. Key longevity factors include using quality fuel, avoiding aggressive surge or backpressure, and letting the turbos cool down before shutting off the engine. A turbo timer or manual idle-down period helps prevent oil coking in the turbo bearings.

External Resources

For more detailed specifications and product support, visit the official Hellion Turbo website. Tuning expertise can be found at Hemi Tuner, a community resource for HEMI performance. For installation walkthroughs and owner experiences, check out the ChallengerTalk forum, which has extensive threads on twin-turbo upgrades.

Conclusion

Upgrading to a Hellion TwinTurbo System is one of the most effective paths to explosive power for the Dodge Challenger. With gains exceeding 200 horsepower even on mild boost, the system transforms a fast car into a genuine monster. However, the installation is not a weekend project for the faint of heart—it requires careful planning, mechanical skill, and a commitment to post-installation tuning and maintenance. For those who invest the time and resources, the reward is a unique, high-performance vehicle that can compete with the most powerful modern muscle cars. Whether you are chasing quarter-mile times or simply want an unforgettable street experience, the Hellion TwinTurbo System delivers on its promise.