Twin Turbo Kits for the Challenger: Hellion and Beyond
Want big power without the bulk of a roots blower? Twin turbo kits for the Challenger exist and they're impressive — but they're also complex builds that require serious supporting work. Here's the complete picture.
Why Turbo Instead of Supercharger?
The Challenger's forced induction aftermarket is dominated by superchargers — Whipple, Magnuson, Procharger, Vortech. But turbochargers offer some genuine advantages:
- Higher peak efficiency: Turbochargers convert exhaust energy to boost without the parasitic drag of a belt-driven supercharger
- Ability to make more power per psi of boost: Turbo air is typically cooler per unit pressure than centrifugal supercharger air
- Compound/stacked setups: Adding turbos to an existing Hellcat supercharger for extreme power
The Main Option: Hellion Street Sleeper
Hellion Turbo is the dominant provider of bolt-on twin turbo kits for the 5.7L, 6.4L, and 6.2L HEMI. Their "Street Sleeper" system earns that name — the turbos mount tucked away under the car, invisible from normal viewing angles.
Hellion Street Sleeper for 5.7L/6.4L HEMI:
- Twin 62mm turbos standard (76mm upgrade available)
- Air-to-air front-mount intercooler
- Complete manifold and downpipe package
- Designed for 500–700 HP on stock motor (5.7L at 6–8 psi)
- Up to 900+ HP with built internals on larger turbos
- Price: $6,000–$8,500 for the complete kit
Installation complexity: High. The system requires:
- Full exhaust manifold replacement
- Intercooler routing through the front bumper
- Fuel system upgrades (injectors, fuel pump) at any significant power level
- Custom or heavily revised PCM tune
Supporting Modifications Required
At 6–8 psi (modest boost, ~150–200 HP gain):
- Injectors: 60–75 lb/hr
- Tune: Mandatory
- E85 or methanol injection: Recommended for knock margin
At 10–15 psi (aggressive street/strip, 250–350 HP gain):
- Forged connecting rods: Mandatory — stock Apache or cast rods will not survive
- Forged pistons: Strongly recommended
- Valve springs: Higher pressure springs for boost conditions
- External oil cooler: Recommended
- Quality fuel system (in-tank pump + surge tank for extreme demands)
Power Numbers
| Setup | Boost | Approx Power |
|---|---|---|
| 5.7L + twin 62mm, 6 psi | Mild | ~520 WHP |
| 6.4L + twin 62mm, 8 psi | Street | ~620 WHP |
| 6.4L + twin 76mm, 12 psi | Built motor | ~800+ WHP |
| Hellcat + twin turbo compound | Variable | 1,200+ WHP |
The Compound Setup (Hellcat + Turbos)
Perhaps the most insane factory-based build available: adding the Hellion twin turbo system to a Hellcat (which already has a factory supercharger). The turbos pressurize the intake of the supercharger, which then provides additional boost on top.
This "compound boost" setup is capable of exceeding 1,500 HP on a built engine. It is a full race build — not a street car at that level.
Turbo vs Supercharger for the Street
For a street-driven daily driver, a supercharger kit is typically easier to live with:
- Instant boost, no spool delay
- Simpler installation
- Better idle manners
- Easier tuning
Turbo kits are the choice when maximum power potential and efficiency matter more than simplicity.
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