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Shop 4.0L

Upgrade Your 4.0L Engine with FastHemis The 4.0L inline-six engine is known for its durability and smooth power delivery, commonly found in Jeep models like the Wrangler and Cherokee. Its robust design offers a solid foundation for both daily driving reliability and moderate performance enhancements. At FastHemis, you'll find a range of parts tailored to the 4.0L platform, including intake and exhaust upgrades, ignition components, and tuning accessories. These parts help improve throttle response, efficiency, and overall engine capability without compromising the engine’s legendary reliability. Key upgrades for your 4.0L engine include: - High-flow air intake systems - Performance exhaust components - Ignition and spark upgrades - Engine management and tuning tools Shop 4.0L engine upgrades at FastHemis.
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1033 Results

American Brother Designs Hitch Cover 2" Receiver: Durango, Jeep & Ram Models
American Brother Designs Hitch Cover 2" Receiver: Durango, Jeep & Ram Models
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American Brother Designs Hitch Cover 2" Receiver: Durango, Jeep & Ram Models

American Brother Designs

Regular price $108.00 $58.00 46% off

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ANZO Tail Lights (Red/Clear): Jeep Grand Cherokee 1999 - 2004
ANZO Tail Lights (Red/Clear): Jeep Grand Cherokee 1999 - 2004
ANZO Tail Lights (Black): Jeep Grand Cherokee 1993 - 1998
ANZO Tail Lights (Black): Jeep Grand Cherokee 1993 - 1998
S&B Cold Air Intake: Jeep Wrangler TJ 4.0L 1997 - 2006
S&B Cold Air Intake: Jeep Wrangler TJ 4.0L 1997 - 2006
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S&B Cold Air Intake: Jeep Wrangler TJ 4.0L 1997 - 2006

S&B Filters

Regular price $429.99 $379.00 12% off

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2 filter types
  • Cotton Cleanable
  • Dry Extendable
Bilstein B8 5100 Shock Absorber Rear 3.5-6" Lift Long Arm: Jeep Wrangler TJ 1997-2006
Bilstein B8 5100 Shock Absorber Rear 3.5-6" Lift Long Arm: Jeep Wrangler TJ 1997-2006

Bilstein B8 5100 Shock Absorber Rear 3.5-6" Lift Long Arm: Jeep Wrangler TJ 1997-2006

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Shock Absorber Rear 3.5-4" Lift Short Arm: Jeep Wrangler TJ 1997-2006
Bilstein B8 5100 Shock Absorber Rear 3.5-4" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein B8 5100 Shock Absorber Rear 3.5-4" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Rear Shock: Jeep Grand Cherokee 1993 - 1998 (w/ 1.5-2" Rear Lift)
Bilstein B8 5100 Rear Shock: Jeep Grand Cherokee 1993 - 1998 (w/ 1.5-2" Rear Lift)

Bilstein B8 5100 Rear Shock: Jeep Grand Cherokee 1993 - 1998 (w/ 1.5-2" Rear Lift)

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Rear Shock: Jeep Grand Cherokee 1999 - 2004 (w/ 3-4" Rear Lift)
Bilstein B8 5100 Rear Shock: Jeep Grand Cherokee 1999 - 2004 (w/ 3-4" Rear Lift)

Bilstein B8 5100 Rear Shock: Jeep Grand Cherokee 1999 - 2004 (w/ 3-4" Rear Lift)

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Shock Absorber Rear 6" Lift: Jeep Grand Cherokee ZJ 1993-1998
Bilstein B8 5100 Shock Absorber Rear 6" Lift: Jeep Grand Cherokee ZJ 1993-1998

Bilstein B8 5100 Shock Absorber Rear 6" Lift: Jeep Grand Cherokee ZJ 1993-1998

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Shock Absorber Front 3.5-4" Lift Short Arm: Jeep Wrangler TJ 1997-2006
Bilstein B8 5100 Shock Absorber Front 3.5-4" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein B8 5100 Shock Absorber Front 3.5-4" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Front Shock: Jeep Wrangler TJ 1997 - 2006 (w/ 4.5" Front Lift & Long Arm Lift Kit)
Bilstein B8 5100 Front Shock: Jeep Wrangler TJ 1997 - 2006 (w/ 4.5" Front Lift & Long Arm Lift Kit)

Bilstein B8 5100 Front Shock: Jeep Wrangler TJ 1997 - 2006 (w/ 4.5" Front Lift & Long Arm Lift Kit)

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Shock Absorber Rear 3-4" Lift: Jeep Grand Cherokee ZJ 1993-1998
Bilstein B8 5100 Shock Absorber Rear 3-4" Lift: Jeep Grand Cherokee ZJ 1993-1998

Bilstein B8 5100 Shock Absorber Rear 3-4" Lift: Jeep Grand Cherokee ZJ 1993-1998

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Front Shock Absorber 3" Lift: Jeep Grand Cherokee ZJ 1993-1998
Bilstein B8 5100 Front Shock Absorber 3" Lift: Jeep Grand Cherokee ZJ 1993-1998

Bilstein B8 5100 Front Shock Absorber 3" Lift: Jeep Grand Cherokee ZJ 1993-1998

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B8 5100 Rear Shock Absorber 3" Lift Short Arm: Jeep Wrangler TJ 1997-2006
Bilstein B8 5100 Rear Shock Absorber 3" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein B8 5100 Rear Shock Absorber 3" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein

Regular price $171.85 $123.00 28% off

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per 

Bilstein B8 5100 Front Shock Absorber 3" Lift Short Arm: Jeep Wrangler TJ 1997-2006
Bilstein B8 5100 Front Shock Absorber 3" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein B8 5100 Front Shock Absorber 3" Lift Short Arm: Jeep Wrangler TJ 1997-2006

Bilstein

Regular price $171.85 $123.00 28% off

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Bilstein B6 4600 Rear Shock: Jeep Grand Cherokee 1999 - 2004 (w/ OEM Ride Height)
Bilstein B6 4600 Rear Shock: Jeep Grand Cherokee 1999 - 2004 (w/ OEM Ride Height)

Bilstein B6 4600 Rear Shock: Jeep Grand Cherokee 1999 - 2004 (w/ OEM Ride Height)

Bilstein

Regular price $136.85 $92.00 33% off

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Bilstein B6 4600 Front Shock: Jeep Grand Cherokee 1999 - 2004 (w/ OEM Ride Height)
Bilstein B6 4600 Front Shock: Jeep Grand Cherokee 1999 - 2004 (w/ OEM Ride Height)

Bilstein B6 4600 Front Shock: Jeep Grand Cherokee 1999 - 2004 (w/ OEM Ride Height)

Bilstein

Regular price $154.85 $104.00 33% off

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Bilstein B6 4600 Rear Shock Absorber (REAR): Jeep Grand Cherokee ZJ 1993-1998
Bilstein B6 4600 Rear Shock Absorber (REAR): Jeep Grand Cherokee ZJ 1993-1998

Bilstein B6 4600 Rear Shock Absorber (REAR): Jeep Grand Cherokee ZJ 1993-1998

Bilstein

Regular price $136.85 $92.00 33% off

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Bilstein B8 5100 Shock Absorber Rear 0-2" Lift (REAR): Jeep Wrangler TJ 1997-2006
Bilstein B8 5100 Shock Absorber Rear 0-2" Lift (REAR): Jeep Wrangler TJ 1997-2006

Bilstein B8 5100 Shock Absorber Rear 0-2" Lift (REAR): Jeep Wrangler TJ 1997-2006

Bilstein

Regular price $171.85 $123.00 28% off

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Eibach 30mm Wheel Spacers (Pair): Jeep Grand Cherokee (93-98) & Wrangler (97-06)
Eibach 30mm Wheel Spacers (Pair): Jeep Grand Cherokee (93-98) & Wrangler (97-06)

Eibach 30mm Wheel Spacers (Pair): Jeep Grand Cherokee (93-98) & Wrangler (97-06)

Eibach

Regular price $261.11 $235.00 10% off

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Borla Touring Cat-Back Exhaust System (Polished Tip): Jeep Wrangler 1997 - 1999 (2.5L & 4.0L)
Borla Touring Cat-Back Exhaust System (Polished Tip): Jeep Wrangler 1997 - 1999 (2.5L & 4.0L)
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Borla Touring Cat-Back Exhaust System (Polished Tip): Jeep Wrangler 1997 - 1999 (2.5L & 4.0L)

Borla

Regular price $799.99 $713.99 11% off

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Borla SS Single Right Rear Exit Cat-Back Exhaust: Jeep Wrangler YJ 4.0L 6cyl 4WD 2Dr 1991 - 1995
Borla SS Single Right Rear Exit Cat-Back Exhaust: Jeep Wrangler YJ 4.0L 6cyl 4WD 2Dr 1991 - 1995
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Borla SS Single Right Rear Exit Cat-Back Exhaust: Jeep Wrangler YJ 4.0L 6cyl 4WD 2Dr 1991 - 1995

Borla

Regular price $716.99 $639.99 11% off

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MBRP Cat Back Exhaust (Single Turndown): Jeep Wrangler TJ Unlimited 4.0L (97-06) - Aluminized
MBRP Cat Back Exhaust (Single Turndown): Jeep Wrangler TJ Unlimited 4.0L (97-06) - Aluminized

MBRP Cat Back Exhaust (Single Turndown): Jeep Wrangler TJ Unlimited 4.0L (97-06) - Aluminized

MBRP

Regular price $333.52 $269.99 19% off

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MBRP Cat Back Exhaust (Single Turndown) (REAR): Jeep Wrangler TJ Unlimited 4.0L (97-06)
MBRP Cat Back Exhaust (Single Turndown) (REAR): Jeep Wrangler TJ Unlimited 4.0L (97-06)

MBRP Cat Back Exhaust (Single Turndown) (REAR): Jeep Wrangler TJ Unlimited 4.0L (97-06)

MBRP

Regular price $401.46 $324.99 19% off

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MBRP Cat Back Exhaust System (Single Side Exit, Black): Jeep Wrangler TJ 1997 - 1999 (2.5L & 4.0L)
MBRP Cat Back Exhaust System (Single Side Exit, Black): Jeep Wrangler TJ 1997 - 1999 (2.5L & 4.0L)
MBRP Cat Back Exhaust (Single Side Exit): Jeep Wrangler TJ (97-06) 2.5L & 4.0L w/ Hardware
MBRP Cat Back Exhaust (Single Side Exit): Jeep Wrangler TJ (97-06) 2.5L & 4.0L w/ Hardware

MBRP Cat Back Exhaust (Single Side Exit): Jeep Wrangler TJ (97-06) 2.5L & 4.0L w/ Hardware

MBRP

Regular price $352.05 $284.99 19% off

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MBRP Cat Back Exhaust System (Single Side Exit): Jeep Wrangler TJ 1997 - 1999 (2.5L & 4.0L)
MBRP Cat Back Exhaust System (Single Side Exit): Jeep Wrangler TJ 1997 - 1999 (2.5L & 4.0L)

MBRP Cat Back Exhaust System (Single Side Exit): Jeep Wrangler TJ 1997 - 1999 (2.5L & 4.0L)

MBRP

Regular price $401.46 $324.99 19% off

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Spec D LED Projector HeadLights (Chrome): Jeep Grand Cherokee 1999 - 2004
Spec D LED Projector HeadLights (Chrome): Jeep Grand Cherokee 1999 - 2004

Spec D LED Projector HeadLights (Chrome): Jeep Grand Cherokee 1999 - 2004

Spec D

Regular price $207.00 $153.00 26% off

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Spec D CCFL Projector Headlights (Black):Jeep Grand Cherokee 1999 - 2004

Spec D CCFL Projector Headlights (Black):Jeep Grand Cherokee 1999 - 2004

Spec D

Regular price $360.00 $267.00 26% off

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Performance Upgrades for Your 4.0L Inline-Six Engine

The 4.0L inline-six engine is a durable and smooth-running powerplant widely recognized in Jeep Wrangler and Cherokee models. Known for its reliability and balanced power delivery, this engine offers a solid base for bolt-on performance enhancements that improve throttle response and efficiency without sacrificing longevity.

Key Performance Upgrades for the 4.0L Engine

Enhancing your 4.0L engine focuses on improving airflow, ignition, and engine management to unlock better throttle response and overall drivability. Popular upgrades include high-flow intake systems that increase air volume, performance exhaust components that reduce backpressure, and ignition upgrades that ensure stronger, more consistent sparks.

  • High-flow air intake systems to boost airflow and efficiency
  • Performance exhaust components for improved scavenging and sound
  • Ignition and spark upgrades to optimize combustion
  • Engine management and tuning tools for precise calibration

How to Maintain Reliability While Upgrading Your 4.0L

The 4.0L engine’s reputation for durability means upgrades should complement its robust design without over-stressing components. Focus on bolt-on parts that enhance performance within the engine’s mechanical limits. Proper tuning and quality parts help maintain reliability while extracting more capability from your engine.

Find the Right 4.0L Engine Parts at FastHemis

At FastHemis, we offer a curated selection of 4.0L engine upgrades designed to improve performance and maintain reliability. Whether you’re looking for intake kits, exhaust solutions, ignition components, or tuning accessories, our parts are fitment-focused and engineered for your Jeep’s inline-six. Shop the 4.0L collection today to enhance your engine’s capability.

SELECT YOUR VEHICLE