SKU: 55905964644

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

Sale price$243.00 Regular price$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
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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]
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SKU: 55905964644

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JBIRD
Fort Morgan, US
★★★★★ 5
Fantastic Read
Format: Hardcover
Fantastic book. Another Incredible work by Lee Smith!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 13, 2026
L
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Lisse
Birmingham, US
★★★★★ 5
A great book by a great journalist
Format: Hardcover
The China Matrix is another great book by the great journalist Lee Smith. The book is written in a very easy to read format. I have learned so many things that I didn't know before, and I simply can't put it down. Lee opened my eyes about the way Washington D.C. works, and I really miss his Epoch TV show, Over the Target. I wish more shows invited him on because he has a great insight when it comes to domestic and international affairs. To whoever wants to learn more about the way the Chinese Community Party works, I recommend to get this book and read it.
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Reviewed in the United States on November 1, 2025
B
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Brett Norton
West Palm Beach, US
★★★★★ 3
Misses some important context, but a solid book
Format: Audiobook
I can't give it the 3.5 stars it deserves. Smith is an outstanding writer and has long view China as an adversary that we intentionally do not pay attention to given the elites make large amounts of money working with the CCP. In this book he demonstrates that happened from the get go, starting with Kissinger. Rarely, if ever, were American interests ever viewed as the lens with which to see China, only as a way to make money for power brokers and businesses alike. He points to Trumps long standing opposition to the way the international trade system evolved and the way it harmed middle class Americans. All of this is outstanding, but the book loses many points trying to cover for terrible protectionist economic policies. We certainly may have gone too far in hollowing out the industrial base, but 100% of Americans benefitted from lower price and more selections. It is not the purpose of the book, but a look at overall US business policy has been to harm Amercians, one need look no further than mass immigration, legal and illegal that drive down wages at the lower/middle end. Nor does the book bother with looking at general business mindless following each other for yet another new fad, from six sigma to who moved my cheese. Again, not what the book is about, but he tries to make the claim that all of this is China and elite policy driving toward this outcome when that data is not supported. Overall, it is a better than worse book that one should read if for no other reason than to see how far we have actually bent over for China for gains that are mostly illusory for business access. That China still uses the elites to gain access not just to markets but US citizen minds is the real problem. Smith does a good job pointing that out
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Reviewed in the United States on October 25, 2025
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Grayfox41
West Palm Beach, US
★★★★★ 5
Yet, so many US consumers take a knee to Chinese imports.
Format: Kindle
My first response to Lee Smith's "The Chinese Matrix" is anger with the CCP. But, they did what treasonous US politicians and investors permitted in exchange for wealth and power. The current situation reminds me of the Chinese finger trap - a small tube of woven reeds just large enough to insert a finger into each end. When naturally trying to withdraw the fingers from opposite ends, the woven reeds constricted. Escape was contrary to natural instinct. Likewise, to extract our country from the Chinese Matrix will require unnatural sacrifice.
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Reviewed in the United States on March 11, 2026
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@Grampa_Steve
Battle Creek, US
★★★★★ 5
Comprehensive and bold analysis of US foreign policy with China.
Format: Kindle
Lee Smith takes the reader through the many years of China appeasement from Kissenger and Nixon to the present where China continues to suck the power of the US toward its goal of global domination.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 9, 2025

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