When constructing a race car, no matter whether it’s a purpose built track machine or a modified production vehicle, car builders try to achieve an aerodynamic balance between drag and downforce. Minimizing drag reduces the air resistance encountered by the car, allowing it to go faster. Downforce is necessary so the tires stay firmly planted on the track surface for optimal power delivery, steering and braking. Diffusers, air dams and side skirts combine to increase down force on race cars. If you want to make your machine look like it’s ready for the track, check out our selection of diffusers.

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    • (4 reviews)
      # sp7298
      Rear Diffuser by Duraflex®. Accelerate the velocity of the airflow underneath your car with this Rear Diffuser. At speed, it'll decrease the pressure under the car with a resulting increase in downforce. Increased downforce will help...
      Helps to elevate your vehicle above the massesProprietary polymer blend for maximum flexibility and strength
      $47.00 - $683.10
    • (0 reviews)
      # sp3073
      Rear Diffuser by VIS Racing®. To give your vehicle a race car look and maximize its aerodynamic characteristics, VIS Racing offers this top-quality rear diffuser. Designed with expert craftsmanship, this part reduces turbulence and...
      Custom designed for your vehicleUpgrades the rear end look
      $228.42 - $1,963.91
    • (2 reviews)
      # sp7334
      Carbon Fiber Rear Diffuser by Carbon Creations®. Accelerate the velocity of the airflow underneath your car with this Rear Diffuser. At speed, the rear diffuser will decrease the pressure under the car with a resulting increase in...
      Racing inspired aerodynamics and styleUsed by professionals in auto racing, drifting and drag racing
      $159.00 - $1,060.00
    • (0 reviews)
      # sp131984
      Aero Rear Diffuser by Vorsteiner®. Material: Autoclaved 1×1 Pre-Preg Carbon Fiber with UV Inhibiting Clear Lacquer Coating. Vorsteiner's Autoclaved Pre-Preg Carbon Fiber structure gives Vorsteiner parts superior stiffness, aerospace...
      Designed with refinement in mind to offer the ultimate in stylePerfect solution to give your vehicle an aggressive yet elegant look
      $1,230.25 - $3,130.25
    • (1 review)
      # sp298
      Carbon Fiber Rear Diffuser by Seibon®. Give your car a high-tech aerodynamic look with this carbon fiber rear diffuser cover. A rear diffuser cover can redirect airflow coming from underneath the car to transition smoothly into the...
      Finished in glossy clear coat that will not chip or flakeAerodynamically designed
      $442.00 - $799.00
    • (0 reviews)
      # sp802
      Rear Diffuser by Aero Function®. Add aggressive visual style to the lower section of your rear bumper cover with an add-on Rear Diffuser from Aero Function. Contoured to fit perfectly on your vehicle, the rear diffuser skirt installs...
      Adds on to the lower section of rear bumper cover to add more aggressive styleEnhances aerodynamics with contours that reduce airflow drag
      $63.00 - $1,655.10
    • (0 reviews)
      # sp30139
      Rear Diffuser by Liberty Walk®. This diffuser creates a vacuum at the back of the vehicle, which draws air more quickly underneath. Reduce turbulence and ensure the smooth airflow with this top-notch diffuser while making your vehicle...
      Adds a stylish edge to your vehicleWill improve aerodynamics of your auto
      $550.00 - $7,020.00
    • (1 review)
      # sp17214
      Rear Diffuser by Anderson Composites®. If you want to get the most out of your vehicle, this this superior product by Anderson Composites is just what you need. Designed with the utmost care and attention to detail and manufactured from...
      Designed to comply with strict quality standardsManufactured from high-grade materials
      $449.10 - $1,349.10
    • (0 reviews)
      # sp93669
      Rear Diffuser by Agency Power®. Blending sleek, racing style with superior functionality, this superior add-on delivers a mean, intimidating look that commands attention while enhancing aerodynamics and reducing the air drag to boost...
      Sleek, low-profile design adds heart-racing edge to the rear end’s lookIntegrates with the bumper to reduce aerodynamic drag and maximize downforce
      $250.00 - $1,520.91
    • (1 review)
      # sp7321
      Rear Diffuser by RKSport®. An Exhaust Diffuser accelerates the velocity of the airflow underneath the car. At speed, it decreases the pressure under the car with a resulting increase in downforce. Increased downforce helps improve your...
      Adds to the appearance of your vehicleDesigned to increase downforce and traction
      $309.20 - $1,892.06
    • (0 reviews)
      # sp8108
      German Rush™ V10 Style Rear Diffuser by Vertical Doors®. Upgrade the rear end of your automobile with this premium-grade diffuser by Vertical Doors to give it that unique aggressive look that will separate it from the mundane masses....
      Gives your vehicle a stylish race-ready lookHelps increase downforce and aerodynamic efficiency
      $1,595.00 - $2,605.50
    • (0 reviews)
      # sp31833
      Carbon Fiber Diffuser by Buddy Club®. Material: Carbon Fiber. Buddy Club Racing Spec Carbon Fiber Diffuser will not only increase the visual appearance of the car but will also improve the wind resistance at high speeds. Racing Spec...
      Constructed of Carbon FiberFeatures a Beautiful Finish
      $1,600.00
    • (0 reviews)
      # sp47706
      CA Super Coupes™ Rear Diffuser by Vertical Doors®. Upgrade the rear end of your automobile with this premium-grade diffuser by Vertical Doors to give it that unique aggressive look that will separate it from the mundane masses....
      Gives your vehicle a stylish race-ready lookHelps increase downforce and aerodynamic efficiency
      $809.10 - $863.10
    • (0 reviews)
      # sp85848
      Rear Diffuser by ARK Performance®. Equip your vehicle with this superior rear diffuser from ARK Performance to reduce aerodynamic drag and maximize downforce which allows for snappy acceleration, astounding performance, agile handling,...
      Designed to boost your vehicle's style and aerodynamic efficiencyOptimizes airflow to reduce drag and maximize downforce
      $254.15 - $823.65
    • (0 reviews)
      # sp7359
      Rear Diffuser by Borla®. Improve the airflow under your car for increased downforce while giving it great race track looks with this Rear Diffuser. It’s the perfect complement to your Borla exhaust system. The Rear Diffuser is made...
      Reduces turbulence and drag at the mufflers and underbodyImproves airflow for increased downforce
      $315.99 - $696.99
    • (0 reviews)
      # sp49250
      Rear Diffuser by KBD®. 1 Piece. Material: Polyurethane. Comes unpainted. Add a sporty look to your prized vehicle with this cutting-edge rear diffuser from KBD. This eye-catching upgrade instantly provides a dash of that heart-racing...
      Designed to accelerate the flow of air under the carIncreases downforce and improves aerodynamic grip
      $220.00 - $559.20
    • (1 review)
      # sp7344
      Havoc Rear Diffuser by IVS®. This kit is just what you need to achieve that very style you've seen in a magazine. All the components are reaction injection molded urethane and ensure the same perfect durability, fit, and finish as OEM...
      Adds a sporty look to your carGreatly improves aerodynamics
      $637.50 - $841.50
    • (0 reviews)
      # sp121655
      C7 Revorix Style Rear Diffuser by DefenderWorx®. 2 Pieces. Turn your valuable investment into an extra-ordinary racing machine on the streets with this top-of-the-range diffuser designed by DefenderWorx. This first-grade product is...
      Perfect to add a touch of sportiness to your vehicle’s profileHelps to increase traction and stability on the racetrack
      $2,034.23 - $2,671.24
    • (0 reviews)
      # sp131977
      Aero Bumper by Vorsteiner®. Vorsteiner is proud to announce the anticipated launch of the lightweight carbon fiber aerodynamic product line for your vehicle. Vorsteiner's Autoclaved Pre-Preg Carbon Fiber structure gives Vorsteiner...
      Designed with refinement in mind to offer the ultimate in stylePerfect solution to give your vehicle an aggressive yet elegant look
      $2,370.25 - $9,495.25
    • (1 review)
      # sp127810
      Rear Diffuser by Chrome & Carbon®. This product is a fantastic solution for those who want to dress up their vehicle and make it look distinctive. Its breakthrough design, top-quality materials, and unique design will surely make you...
      Designed to customize your vehicle and give it a unique lookPerfect way to elevate your automobile above the masses
      $765.00 - $1,162.80
    • (0 reviews)
      # sp132877
      VZ3 Style Polyurethane Rear Diffuser by Vicrez®. This top-grade product is expertly made in compliance with stringent industry standards to offer a fusion of a well-balanced design and high level of craftsmanship. Manufactured from...
      OEM - Fitment, Quality, DurabilityPolyurethane is Practically Unbreakable
      $689.00 - $749.00
    • (0 reviews)
      # sp127495
      Rear Bumper with Diffuser by D2S®. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind, this product by D2S will last a lifetime. It will...
      Custom high performance styleComes with everything required for installation
      $384.18 - $8,799.34
    • (0 reviews)
      # mpn4495456661
      Exhaust Shield by AutoTecknic®. Material: Carbon Fiber. Installation Type: Clip-In. Carbon Type: Twill Weave. This is AutoTecknic's brand new pre-preg dry carbon fiber exhaust shield cover. It is made with 2x2 twill weave carbon fiber...
      Engineered to provide easy installationUnsurpassed in design and performance
      $400.00
    • (0 reviews)
      # mpn4222239683
      Rear Diffuser Undertray by APR Performance®. Material: Carbon Fiber. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind. It will meet your...
      Built to take quality to a new level and deliver peak performanceMeticulously engineered with top-of-the-line technology
      $403.75
    • (0 reviews)
      # sp104575
      Exhaust Heat Shield by APR Performance®. Dress-up the exterior with carbon fiber, molded to precise dimensions that only pre-preg. materials can achieve.  These parts are exotic-looking, race-inspired, and are unmatched in quality.
      Pre-preg. Carbon fiber manufacturing process exhaust heat shields are vacuum-bagged and cured in the autoclave at high temperatures, ensuring quality, durability, and extremely-high strengh-to-weight ratiosFade-resistant clear coat exhaust heat shields are finished with UV-stable, production clear coat paint, then individually hand-polished to a brilliant shine
      $135.15 - $382.50
    • (0 reviews)
      # sp104580
      Rear Diffuser by APR Performance®. Material: Carbon Fiber. Diffusers work in conjunction with other aerodynamic components of a car to help produce downforce. Because a car displaces air as it moves forward, the air molecules in the...
      Reduce overall liftCut down on drag-inducing turbulence
      $487.90 - $1,827.50
    • (0 reviews)
      # mpn4222239418
      Rear Diffuser Led Set by APR Performance®. Material: Carbon Fiber. APR Performance Rear Diffusers integrate with the rear bumper area to to reduce overall lift and drag. Formed in the autoclave at high temperatures, APR Performance Rear...
      Reduce overall liftCut down on drag-inducing turbulence
      $12.75
    • (0 reviews)
      # sp107078
      HEC Replica Style Carbon Fiber Rear Diffuser by Vertical Doors®. Material: Carbon Fiber. Upgrade the rear end of your automobile with this premium-grade diffuser by Vertical Doors to give it that unique aggressive look that will...
      Gives your vehicle a stylish race-ready lookHelps increase downforce and aerodynamic efficiency
      $810.00 - $1,709.10
    • (0 reviews)
      # mpn4493911768
      Rear Diffuser by 3d Carbon®. Material: Carbon Fiber. Add aggressive visual style to the lower section of your rear bumper cover with a replacement Rear Lower Diffuser from 3dCarbon. Contoured to fit perfectly on your vehicle, the lower...
      Replaces the lower section of rear bumper cover to add more aggressive styleBolts on directly to factory original mounting points
      $748.85
    • (0 reviews)
      # sp114356
      Carbon Fiber Rear Diffuser by Akrapovic®. The stunning carbon-fibre diffuser is offered as an option with the choice of a high-gloss or matte finish. It is a completely new design from the one that comes as standard on the car, and it...
      Unique and innovative design, unsurpassed valueIntegrates with the bumper to reduce aerodynamic drag and maximize downforce
      $1,104.45 - $2,804.55




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    Although some body mods increase drag to create downforce, this tradeoff is necessary for overall vehicle performance. However, there are component choices a builder can make that maximize downforce without creating excessive drag. Such is the case with a rear diffuser. When combined with an air dam and side skirts, a rear diffuser functions to increase the velocity of the air flowing underneath the car and increase downforce and traction at the tires.

    According to Bernoulli’s Principle, when the velocity of air increases, its pressure decreases. This means that the air pressure above the car is greater, and this greater pressure exerted downward provides the necessary downforce. Although components like rear wings can also be used to provide downforce, they create much more aerodynamic drag while doing so than a rear diffuser. The diffuser provides the space for the high velocity, low pressure air flow to decelerate and expand at the rear of the vehicle, creating a pressure differential and more downforce. Diffusers also typically have dividers that allow the air flow to transition to the airstream at the back of the car without creating turbulence and drag.

    Of course, the above description applies mainly to a car constructed expressly for racing. Such cars usually have smoother undercarriages to facilitate the increased air flow velocity, and they are driven at much higher speeds than are allowable on the highway, so the average street driven car will not realize all of a diffuser’s benefits. But we know that the visual appeal of a custom rear diffuser and aerodynamic body components in general is just as, if not more important to street driven car owners than functionality, which is why we have the extensive selection of diffusers you see on the page before you.

    We offer rear diffusers for most popular cars in materials including carbon fiber, aluminum, urethane, fiberglass, fiberglass composite, ABS plastic and stainless steel. Depending on application, some are designed to be a fully custom addition, while others are replacements for the OE diffuser but are manufactured in an upgraded material like carbon fiber. Some applications are designed to be used with specific exhaust systems. And because each of our rear diffusers is carefully designed for a specific model, regardless of your choice you can count on ease of fitment, and an appearance that will command attention and perfectly complement your vehicle’s styling.

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    Diffusers Reviews

    Average rating:  4.5  4.5 - 13 reviews
    4 of 5
    Rear Diffuser
    It looks amazing and was a really easy piece to install. Only issue is that it is a really tight fit. Since the carbon fiber has zero give the corners do pop out a little bit. Nothing that is going to cause it to fall off or anything, but you do constantly need to hit them back in after driving.
    JPosted by Jason (Puyallup, WA) / March 13, 2018
    2015 Dodge Charger
    Was this review helpful for you? Yes
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