SKU: 55905964644

JB4 Tuner for Subaru WRX, Ascent, Legacy, & Outback

$243.00 $270.00
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Description

JB4 Tuner for Subaru WRX, Ascent, Legacy, & OutbackPower gains of up to 50hp to the wheels on a stock vehicle The JB4 is the most advanced and highly featured tuning system for your Subaru 2. 4L 4 cylinder turbo. Power gains are up to 50hp to the wheels (70hp crank) on a completely stock car on pump gas, and gains with ethanol mixtures and bolt on parts are even higher. The JB4 features a simple plug & play installation harness for easy installation & removal and includes many features not found with

Power gains of up to 50hp to the wheels on a stock vehicle

The JB4 is the most advanced and highly featured tuning system for your Subaru 2.4L 4 cylinder turbo. Power gains are up to 50hp to the wheels (70hp crank) on a completely stock car on pump gas, and gains with ethanol mixtures and bolt-on parts are even higher.

The JB4 features a simple plug & play installation harness for easy installation & removal and includes many features not found with any other tune. Including on the fly map switching from your phone/tablet instead between factory and various performance maps, boost limiting by gear for improved traction in lower gears, progressive water/methanol support, built-in data logging, built-in code reading, and much more.

Wirelessly Connect to your JB4: Grab our all-new JB4 PRO smartphone connection to wirelessly connect the JB4 BMW tuner to your Bluetooth 4.0 compatible iOS or Android device. This option allows you to record and analyze vehicle and tuning data, change JB4 performance maps, and update JB4 firmware as we release free newer versions with updates, more powerful maps, and new features under development. Our new adapter fits fully inside the JB4 enclosure for enhanced weather protection and a more streamlined look. The JB4PRO Free app features an intuitive easy-to-use interface, help buttons, and advanced log analysis tools that can estimate the performance of your car and help identify any tuning concerns. For more info on how to use the JB4PRO free app click here.

Subaru JB4 Features & Benefits

• Power gains of up to 50hp to the wheels on a stock vehicle
• Improves 0-60 times and 1/4 mile times
• Preloaded with custom JB4 Subaru tuning software and up to 8 maps for various fuel and modification levels
• Ethanol (E85) compatible tuning maps
• Able to read/delete fault codes
• View and record up to 30 different gauges/engine parameters in real-time with the JB4PRO app.
• Boost by gear in 1st, 2nd, and 3rd can be controlled via the JB4PRO app for a perfect launch
• Compatible with the FREE JB4PRO app for smartphone logging, tuning changes, and adjustment
• The JB4 offers a lot more performance, functionality, and safety than your average performance chip
• Quick Plug & Play Installation
• CANbus OBDII integration offering unrivaled tuning features and performance
• Improved performance over non-integrated chip tunes
• Runs as smoothly as stock, this is how your vehicle should have come from the factory
• Compatible with all driving modes
• Fuel economy unchanged during normal driving
• 91 octane fuel or better required for performance gains
• Not VIN locked and can be removed without a trace and resold down the road
• Includes the rugged JB4 billet aluminum enclosure for protection
• Designed and assembled in USA
• 5 year warranty

Vehicle Fitment

• 2022+ Subaru WRX 2.4L 4 cyl. Turbo
• 2019+ Subaru Ascent 2.4L 4 cyl. Turbo
• 2020+ Subaru Legacy XT 2.4L 4 cyl. Turbo
• 2020+ Subaru Outback XT 2.4L 4 cyl. Turbo

What is a JB4?

The JB4 is a plug & play tune available for turbocharged vehicles. The JB4 tuner installs between your car's sensors and the DME/ECU (computer) and manipulates vehicle performance through these connections making your vehicle much faster. While it's not the only tuning system that operates this way the JB4 separates itself from the competition with much more advanced connection points and processing including CANbus, fuel & spark control, Bluetooth to your smartphone, and a variety of innovative and advanced features not possible with any other system. BMS regularly publishes free mapping and firmware updates adding performance and features as ongoing development allows. In addition, the JB4 system is not VIN-locked to your vehicle and can quickly be removed and swapped between cars or resold at a later time. Often imitated but never duplicated the JB4 has been the gold standard in plug and play turbocharged performance tuning for over a decade and is sold in over 67 countries worldwide.

Is the JB4 a real tune?

Yes the JB4 is a real tune. By tapping into specific sensors and CANbus for real time vehicle data the JB4 is able to alter your boost, timing, AFR, and/or fuel trims, to a similar degree an ECU reflash would, but without the vehicle ever knowing its been tuned. The result is safe, smooth, and significant power and torque gains while retaining your factory safety systems and without having to unlock/flag your ECU.




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Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 55905964644

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Thunderboltmysql
Massapequa, US
★★★★★ 4
Nice Suit - Light Gray Color OF Suit IS Not A Solid Light Gray, It Has Linear Designs
Size: 12, Color: Light Grey, Size: 12, Color: Light Grey
I had purchased this polyester and linen blend suit for my son, in size 12Y for him in the color light gray. The color of the suit depicted in the advertisement arrived to be a bit different upon arrival. It's not a solid color light gray, it actually has small black liner lines dispersed all over the suit. The coat features a single button in the center, and there are two side pockets fairly decent sized. Unfortunately right above the pockets are red colored lineal horizontal lines. I don't think those lines are part of the coat's design, there definitely is some printing malfunction. It is hard to see in the pictures advertised, you can see it in the pictures and video I have posted clearly. The material of the suit is fairly acceptable, actually better than expected. The child can actually wear it multiple times for various occasions. The suit emits grace along with acceptable stitching in every apparel along with the bowtie. The suit did arrive in a slide bag all folded up, so there were a number of wrinkles especially on the coat, its as if it had lost its shape. I will definitely need to steam iron it before it will be worn. Just like the coat has pockets the tailored pants also have two side pockets, and belt loops in case need of belt if the pants are loose. I'm actually glad I had ordered two sizes up because compared to his current measurements the suit is big on, especially the pants waist and length. I had measured the suit myself and below are the measurements. Pants Waist - 15.25 Inches Pants Length - 35.75 Inches Pant's Inseam 25 Inches Coat's Length - 24.5 Inches Coat's Shoulders - About 14.5 Inches Coat's Sleeve Length - 22 Inches Coat's Chest - 15.5 Inches In addition to the suit, I also received a solid colored light gray, bowtie. The bowtie has an adjustable strap, so you can set the bowtie to your comfort in the collar. You can wear it along the suit or without it if needed to match with something and still manage to look a show topper!. The coat has nice shoulder padding therefore it sits across the shoulders nicely having it hold its shape and style. Overall it's not a bad purchase, suits like these always come in handy for a unexpected or expected events. I'm glad I had purchased this suit I'm sure it'll come to use one day.
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Reviewed in the United States on March 10, 2026
A
Verified Purchase
Aletha
Whiting, US
★★★★★ 5
Great Suit!
Size: 5, Color: Sky Blue
It fit well and looked very nice on my son
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Reviewed in the United States on April 17, 2026
C
Coreen Selmon
Whiting, US
★★★★★ 5
Adorable & Stylish Suit
Size: 4, Color: Light Grey
This suit is perfect for special occasions! The linen fabric is lightweight and breathable, great for warmer weather. The slim fit looks sharp, and the light grey color is classy. Comfortable for kids to wear and ideal for weddings or events!
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Reviewed in the United States on April 13, 2026
T
Teacher Lady
Natrona Heights, US
★★★★★ 5
GQ KIDS...For the love of being FLY!
Size: 8, Color: Sky Blue
I am highly suggesting this suit for purchase because the color alone is a standout and will have people asking where did you get the suit from? The length of the bowtie is adjustable, the color is bright and lively, the fabric is pure quality. You can run a hot iron over it or a steamer to get the fold lines out of it from how it was packaged, but it seems that even if you just hung it up in the bathroom while running a hot shower, the wrinkling would drop. I think the purchase price is good for all that you get which is a quality blazer, great slacks and a bowtie. It's a one stop shop for a graduation event, dinner, a formal party or even a photoshoot. My nephew wears a size 7 or 6-8, so I ordered a size 8 to be safe and it fits nicely.
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Reviewed in the United States on February 25, 2026
A
Amazon Customer
Los Angeles, US
★★★★★ 4
Cute sky blue linen suit for toddler!
Size: 3, Color: Sky Blue, Size: 3, Color: Sky Blue
I got this Trasign Kids Linen Suit in sky blue for my 2 year old, thinking my wife said “blue” (turns out she meant navy or something darker 😅). I actually really like the light, airy sky blue. It’s fresh, summery, and looks adorable on him for photos or special occasions. My wife? Not so much. She immediately said “baby blue ugly” 😅😅 On the plus side: • Soft fabric – linen blend feels gentle and breathable on little skin, no itchiness or stiffness. • Nicely packaged – arrived with very little wrinkling (barely needed steaming), which is a win for linen. • Good fit for a toddler – true to size, easy to button, and the shorts/pants have adjustable waist for growing kids. • Looks sharp once on – the set gives that classic little gentleman vibe without feeling over the top. It’s a quality piece overall, just a classic case of “what one spouse loves, the other doesn’t” on the color. If sky blue works for your family (or you’re shopping solo like me 🤣), it’s a solid buy.
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Reviewed in the United States on February 22, 2026

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