It can be daunting when delving into the world of aftermarket parts and modifications of the Hellcat platform for the first time. Hopefully we can help walk you through some of the most beneficial mods you can install, and what the most logical order to implement them will be!
Engine Support Mods
Everyone likes more power, and sometimes 700+ Horsepower just isn’t quite enough. Let’s walk you through how to increase those numbers while keeping your engine safe and protecting your investment!
Cold Air Intakes Â
CAI’s are a quick and relatively inexpensive way to moderately boost power by allowing the engine and blower to suck in more air. More Air = More Power! Another great benefit of CAI’s on the Hellcat platform in particular is the sound. They greatly increase the sound of the supercharger, making that beautiful whine much louder! We recommend going with either one of the JLT Intakes, or if you want to splurge a little bit go with the Legmaker Intake. They both make similar amounts of power, but whereas the JLT is molded plastic, the Legmaker is a single-piece of handmade carbon fiber that just looks incredible. We have also noticed that the Legmaker Intake does make the supercharger a bit louder than the JLT Intake.
Click here to check out all of our available intakes for your Hellcat Engine!
Make sure to input your vehicle’s year, make and model to confirm the fitment of the intake!
Catch-Cans (Oil-Fuel Separators)
A catch can (oil separator) is a must-have upgrade for the Hellcat platform, which is notorious for oil blowback. Under boost, excess crankcase pressure forces oil vapors into the intake, leading to carbon buildup on valves, reduced octane levels, and even power loss over time. A high-quality catch can traps these oil vapors before they reach the intake, keeping the combustion process clean and maximizing performance. Whether you’re pushing stock power or running high boost, a catch can protects your engine, improves longevity, and ensures your Hellcat runs at peak efficiency.
Hellcat / Demon Catch Can By Mighty Mouse
Oil Catch Can (Hellcat / Trackhawk / Redeye / Demon) Black By J&L Passenger Side Mount
Interchillers
An interchiller is a game-changer for the Hellcat platform, helping to keep intake air temperatures (IATs) in check for maximum performance. Heat soak is a common issue, especially in supercharged applications, leading to power loss and inconsistent performance. By using the vehicle’s A/C system to cool the intercooler fluid, an interchiller drastically lowers IATs, improving horsepower, throttle response, and reliability—especially in hot climates or during back-to-back pulls. Whether on the street or track, an interchiller helps your Hellcat stay cool and perform at its best. We highly recommend interchillers from IC Chiller, offering proven solutions to keep your engine running at peak efficiency.
Pulley, Injectors and Fuel System Upgrades
Hellcats, whether equipped with the 2.4L or 2.7L supercharger, gain significant power with simple upgrades. Make sure to verify that your new pulley isn’t too small, as that could overspin the blower leading to potential failures. Here’s a breakdown of what works best:
For 2.4L Blower Cars (Hellcat, TRX, Trackhawk, Durango Hellcat):
3.1″ Upper Pulley + Tune:Â Adds ~50 WHP with no additional fuel system mods.
2.82″ Upper Pulley + Injectors + Boost-A-Pump:Â Gains ~100 WHP.
Recommended Injectors: We use 775cc injectors in our kit, though some run factory Demon injectors (700cc).
Flex Fuel Setup –Â 2.82″ Upper Pulley + Larger Injectors + Drop-in Pump – Gains ~100 WHP on pump gas, ~150 WHP on E85.
Recommended Injectors: Our flex fuel kits use 1000cc injectors instead of 1300cc because they are more linear and infer alcohol content better.
Straight E85 Max Effort Setup (2.64″ Upper Pulley + ATI 10% Lower + 1300cc Injectors + Dual Pump):Â Gains ~200 WHP.
Recommended Injectors:Â 1300cc injectors for full E85 applications.
For 2.7L Blower Cars (Redeye, 2018 Demon):
3.1″ Upper Pulley + Tune: Adds ~50 WHP with stock injectors
3.1″ Upper Pulley + Larger Injectors:Â Enables flex fuel capabilities.
2.72″ Upper Pulley + ATI Lower + 1300cc Injectors:Â Gains ~200 WHP.
Recommended Injectors: 1300cc injectors for max E85 power.
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Supercharger Upgrades
Supercharger porting is a serious upgrade for those pushing max-effort E85 setups, allowing for increased airflow, improved efficiency, and greater horsepower gains. While it’s not ideal for 2.7L blowers due to their fragility or pump gas setups limited by octane rather than airflow, porting shines when paired with high-boost, high-octane builds. For best results, we recommend SDG’s porting service and upgrading to a Nick Williams 108mm throttle body to maximize airflow and throttle response. If you’re chasing every last bit of power, a properly ported supercharger can help you get there!
Supercharger Porting: Gains ~50 WHP and ~2 PSI of boost.
Not recommended for 2.7L blower cars, as they tend to be more fragile.
Not worthwhile on pump gas since the setup is octane-limited, not airflow-limited—adding boost would require slowing the blower to keep boost at safe levels.
Best for max effort E85 setups.
Recommended Porting Service: SDG.
Recommended Throttle Body: Nick Williams 108mm TB.
Driveshaft Upgrades
In a high-horsepower Hellcat, an upgraded driveshaft is essential for putting power to the pavement without compromise. Factory driveshafts with soft rubber mounts and adapter plates can introduce weak points, limiting performance and durability. The Direct Fit Rear CV Driveshaft from The Driveshaft Shop eliminates these issues with a precision-ground CV joint, shedding unnecessary weight while enhancing power transfer and drivetrain response. Engineered to handle 1,000+ HP, this driveshaft ensures rock-solid connections, perfect alignment, and maximum efficiency, giving your Hellcat the strength it needs to dominate the road or track.
Another alternative is the OEM Redeye Driveshaft straight from MOPAR. Its stronger than the stock Hellcat driveshaft, and when combined with a JXB Driveshaft Center Support Bearing, it is able to handle much more power. This support bearing also helps eliminate harsh vibrations that can be caused from increased power.
Transmission Upgrades
The stock 8HP90 transmission in the Hellcat is strong and well-engineered, handling bolt-ons and moderate power increases without issue. However, when pushing significant horsepower—especially with a built engine or aggressive boost levels—the stock internals become a limiting factor. High torque output, rapid shifts, and repeated abuse can lead to clutch slippage, overheating, and eventual failure.
Upgrading to a built transmission, like those from Sipple Speed and Performance, who specialize in built Hemi Transmissions & Converters, provides reinforced clutch packs, upgraded valve bodies, and improved fluid dynamics to handle the increased power and stress. These modifications enhance shift precision, increase holding capacity, and improve longevity under extreme conditions. Paired with a performance torque converter, a built transmission also optimizes power delivery, reduces drivetrain loss, and ensures smooth yet firm shifts, making it essential for high-horsepower applications. Whether you’re launching hard at the track or putting down big numbers on the dyno, a built transmission ensures your Hellcat can handle the power reliably without risking premature failure.
Rear End & Suspension
Upgrading the rear end and suspension of your Hellcat is crucial for putting power to the ground and improving reliability. A DIRS Differential Brace helps prevent costly diff failures, while a Wavetrac LSD upgrade ensures consistent traction when the factory unit wears out. The AAD Drag Pak Suspension eliminates wheel hop, giving you better launches and smoother acceleration. If you’re looking to run 15-inch rear wheels, our brake conversion kit has you covered. To tighten up handling and stability, the BMR Rear Cradle Lockout Kit locks down the rear cradle, reducing flex. These upgrades maximize performance, traction, and durability, making your Hellcat more capable on the street or track.
- DIRS Differential Brace: A must-have for preventing diff failures.
- Wavetrac LSD Upgrade: We developed and sell a Wavetrac limited-slip differential for the ZF rear when the factory LSD wears out.
- AAD Drag Pak Suspension: Best suspension package to eliminate wheel hop.
- 15-Inch Brake Conversion Kit: If you want to run 15-inch rear wheels, we offer a complete brake conversion package.
- BMR Rear Cradle Lockout Kit: Essential for locking out the rear cradle and improving stability.