Supercharger Lid and Blower Pulley Upgrades: What They Do and What They Cost
A smaller blower pulley or ported lid is the first and most cost-effective upgrade for any Hellcat or Redeye.
The Supercharger System Basics
The Hellcat's 2.4L Roots-type supercharger is belt-driven off the crankshaft. The ratio of the crank pulley diameter to the blower pulley diameter determines how fast the supercharger spins. Faster spin = more boost.
Lid Porting
The supercharger lid houses the throttle body and the inlet to the blower rotors. Factory lids have casting restrictions that limit airflow.
What porting does: Enlarges and smooths the inlet passages, reducing restriction and improving mass flow. A ported lid typically adds 20–40 hp on a stock-boost Hellcat without changing boost levels.
Who does it: STS Turbo, SHR, Lethal Performance, and others offer ported Hellcat lids.
Cost: $400–700 for the ported lid exchange service. Worth doing before spending on pulleys.
Smaller Blower Pulley (Underdrive Pulley)
Replacing the 2.65" factory blower pulley with a smaller pulley spins the blower faster, generating more boost.
Common upgrades:
- 2.45" pulley: ~1–1.5 psi more boost, 30–50 hp gain
- 2.40" pulley: ~1.5–2 psi more boost, 40–60 hp gain
- 2.10" pulley (aggressive): Requires upgraded fuel system and tune, significant cooling demands
Important: Pulley upgrades require a tune. Running more boost without recalibrating fuel and ignition causes detonation.
The Lid + Pulley Combo
The most popular Hellcat first step: ported lid + 2.45" pulley + E85 tune.
Expected gains on a stock Hellcat:
- From 707 hp at the crank to approximately 620–650 whp
- Quarter mile improvement: typically 0.3–0.5 seconds off the stock ET
Supporting Mods Required
- Upgraded spark plugs (one heat range colder, 0.035" gap)
- Tune calibrated for the new boost level
- Verify fuel pump can support increased demand
- Consider heat exchanger coolant upgrade for sustained use
Related Articles
Wheel Offset Explained for 2022 Challenger Owners
Offset decides whether an aftermarket wheel tucks in, sits flush, or rubs. Here is the beginner-friendly way to read offset before buying wheels for a Challenger.
Backspacing vs Offset: The Wheel Fitment Terms That Get Mixed Up
Offset and backspacing describe related fitment ideas, but they are not the same number. Understanding both helps prevent rubbing and brake-clearance mistakes.
Narrowbody vs Widebody Challenger Fitment: What Actually Changes?
Widebody Challengers can support wider factory-style tire packages, but that does not mean every wide wheel fits every car. Here is what changes.