Predator Performance Upper Pulley — Every Question Answered

We get calls about upper pulleys every week. Same questions keep coming up, so we built this reference to settle them once and for all. If you are running a 6.2L Hellcat, Redeye, or Jailbreak engine — Challenger, Charger, Durango SRT, or Ram 1500 TRX — this covers what you need to know before you order.

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What does an upper pulley actually do?

The upper pulley sits on the supercharger snout and drives the rotors via the belt. A smaller diameter pulley increases rotor speed relative to crankshaft speed — that is overdrive. More rotor speed means more airflow through the TVS rotor pack, which means higher manifold pressure (boost).

Every millimeter you take off the pulley diameter increases rotor speed and lift pressure. The stock 2.65-inch upper pulley on the 6.2L Hellcat produces roughly 11–11.5 psi of boost at the manifold. Swap to a 2.45-inch pulley and you are looking at approximately 14–15 psi, depending on belt slip, heat, and intake air temperature.

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Do I need a tune with an upper pulley?

Yes. Full stop.

The factory PCM is calibrated for stock boost and stock airflow. When you add a smaller pulley, you are pushing more air into the engine than the factory fuel tables account for. Without a tune, the engine will run lean under boost — lean combustion is the fastest path to detonation and piston damage.

A proper tune on a wideband dyno corrects air/fuel ratio across the RPM range, adjusts ignition timing to match the new boost curve, and raises the boost limit set in the PCM. Running an upper pulley on a stock tune is not a grey area — it is a way to damage an expensive engine.

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Will the Predator pulley work without any other supporting mods?

The Predator Performance upper pulley is a bolt-on modification. You do not need a cold air intake, ported snout, or upgraded belt to install the pulley itself. However:

- A tune is required — see above. - Belt slippage becomes a real concern on aggressive pulley sizes. If you are going below 2.40 inches, a belt tensioner upgrade and a Gates/Dayco high-grip belt are strongly recommended. - Charge air temperatures will rise with increased boost. If you are in a hot climate or doing sustained pulls, an upgraded intercooler or water-methanol injection becomes a practical consideration — not a requirement at modest overdrive, but something to plan for.

At the 2.45–2.55 inch range, most owners run the pulley with a tune and nothing else on a daily-driven car without issues.

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What boost levels can I expect from each pulley size?

These are real-world street estimates at wide-open throttle with a healthy belt and no boost leak. Dyno numbers on a calibrated load cell will differ slightly based on altitude, IAT, and individual engine tolerance.

| Pulley Size | Estimated Boost | Notes | |---|---|---| | 2.65" (stock) | 11–11.5 psi | Factory calibration | | 2.55" | 12.5–13 psi | Popular first step | | 2.45" | 14–15 psi | Belt upgrade recommended | | 2.35" | 16–17 psi | Belt + tensioner upgrade required, supporting mods advised | | 2.25" and smaller | 18+ psi | Heat management and forged internals become a serious discussion |

Important: These are manifold pressure estimates, not crank horsepower claims. Actual power output depends on your tune, exhaust, intake, and the health of your engine.

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How much horsepower will I gain?

We will not give you a number, and you should be skeptical of anyone who does without dyno data specific to your car and tune.

What we can say: with a quality tune and a step to approximately 2.45 inches on a stock 707 HP Hellcat, gains of 35–60 wheel horsepower are commonly reported on a chassis dyno. The range is wide because tune quality, octane, IAT, and your starting baseline all matter.

If you want a real number, the only honest answer comes from a before/after pull on the same dyno, same day, same conditions.

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Is it safe for a daily driver?

At conservative overdrive (2.55" to 2.45") with a proper tune, yes — the Hellcat engine is built with enough headroom to handle modest boost increases reliably. FCA engineered these engines with forged internals and a robust oiling system precisely because they knew enthusiasts would push them.

At 2.35" and smaller, you are getting into territory where daily use demands more attention to IATs, oil changes, and listening for detonation. It is not inherently unsafe, but it is not set-it-and-forget-it either.

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What is the smallest safe pulley size without forged internals?

This is a reasonable question with no single correct answer — it depends on your tune, fuel quality, climate, and how hard you drive the car.

As a general working reference used in the Hellcat community: - 2.45" to 2.55": Low risk on a proper tune with 93 octane - 2.35": Manageable with conservative timing and quality fuel; E85 or flex fuel is advisable - 2.25" and smaller: Recommended only with forged pistons, upgraded rods, or proven E85/race fuel tune

Your tuner's opinion based on your specific car, climate, and use case should override any general guidance.

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What tools do I need for installation?

The upper pulley swap is a manageable DIY job with a few specific tools:

- Supercharger pulley removal/installation tool (specific to TVS2300/2650 snout — do not improvise) - Serpentine belt tool or long breaker bar for tensioner relief - Torque wrench (confirm torque spec with your specific pulley kit documentation) - Thread locker (supplied with the Predator kit — do not skip this)

Plan for 45–90 minutes on a cold engine with the car on a lift or level ground. The procedure is not complex, but using the correct pulley tool is non-negotiable — you can crack the snout housing forcing an undersized socket.

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Does it fit the Challenger Widebody and Durango SRT?

The Predator Performance upper pulley is compatible with all 6.2L TVS-equipped platforms: - Dodge Challenger SRT Hellcat (2015+) - Dodge Charger SRT Hellcat (2015+) - Jeep Grand Cherokee Trackhawk (2017+) - Ram 1500 TRX (2021+) - Dodge Durango SRT Hellcat (2021)

Fitment is based on the supercharger snout, not the chassis. Confirm your exact build year and supercharger variant (2.4L vs 2.7L) before ordering — the Redeye and Demon use a different snout diameter.

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Can I combine an upper pulley with a ported snout?

Yes, and this is a common combination. A ported supercharger snout reduces inlet restriction and improves airflow efficiency — it does not increase boost by itself, but it allows the rotors to move more air at the same rotor speed compared to a stock snout.

Combining a ported snout with an upper pulley gets more from both modifications: the porting reduces heat and pressure drop at the inlet, and the smaller pulley raises rotor speed to take advantage of the improved flow path. Many owners in the 600–650 WHP range are running exactly this combination.

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Where do I buy the Predator Performance pulley?

We carry the Predator Performance upper pulley kit with the correct pulley tool and hardware for all 6.2L Hellcat platforms. Stock and sizing options are on our product page — and if you have questions before ordering, call us directly. We will tell you what size makes sense for your car and your goals, not just sell you the most aggressive option on the shelf.

Predator Pulley FAQ – FAS Motorsports Summary

Below is a condensed, customer-facing version of your Predator Pulley FAQ, preserving your technical points and shop perspective while tightening structure and flow.

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What is a Predator Pulley?

The Predator Pulley is a lower crank pulley swap (with a matching belt, and sometimes a corresponding upper) that overdrives the factory IHI 2.4L or 2.7L supercharger on Hellcat-family vehicles.

• It increases pulley ratio, so the blower spins faster and makes more boost.
• Typical kit: lower pulley, updated belt, and on some SKUs an upper pulley to keep the accessory drive in spec.

It is not:

• A tune
• A complete supercharger
• A port job

It’s a mechanical change to pulley ratio, nothing more, nothing less.

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1. Will this fit my Hellcat / Trackhawk / TRX / Demon?

The Predator Pulley platform supports most factory IHI 2.4L and 2.7L–equipped vehicles:

• Hellcat (2.4L)
• Trackhawk
• TRX
• Demon / Redeye (2.7L)

If you have anything non-stock on the blower side, call before you buy:

• Aftermarket cog drive
• 2.7L swap on a 2.4L car
• TVS or other blower conversion

Pulley ratio math changes with blower size and drive type.