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6.5 Universal Speaker Adapter Ring Set- Subaru
Great product with perfect fit. I installed the Alpine SPS-6 ..
5 of 5 Stars!
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Subaru GR Stumble Fuel Kit Fix, similar to 315100

Subaru GR Stumble Fuel Kit Fix, similar to 315100


  • 2008-2017 STi

Years ago, Subaru started implementing fuel dampeners to smooth out the fuel flow both to and from the engine, resulting in a smoother transitioning throttle. In 2008, these prior generation dampeners were removed and replaced with a Dampener/Fuel Pressure regulator combination, found only on the STi model. Although this factory combination works well on stock STIs, it can exhibit a flat spot in power between 2,000 and 3,000 RPM as modifications are added to the car. Other common names for this situation are: flat spot, GR Stumble, Lean Spot, Headache!, ETC. What's worse, the lean spot becomes more apparent as larger injectors and or fuel pump are installed.

We decided it was time to resolve the flat spot once and for all. Through countless data logging hours we were able to design one of the best solutions on the market for the GR stumble. What's even better, this stock appearing fuel kit can be installed in under 10 minutes with basic tools. The kit is composed of both Subaru factory and high quality aftermarket parts. With the addition of our kit, and proper tuning, you will finally regain a smooth power band. If you do not have a tuner nearby, or one that is capable of fixing the flat spot, then feel free to contact our E-Tuning department .

Similar to our kit, COBB's 315100, implements the same concepts and tuning, but slightly different visual appearances. Our kit was released in 2013, COBB was 2014.

Sold as a kit.

High Pressure Fuel hose

  • 900 psi burst fuel hose is designed specifically for fuel injected vehicles and is resist to gasoline, oil, diesel, e85, and other fuels. This hose meets SAE specification J30R9.

Subaru Fuel Pressure Regulator (FPR)

  • By using a high quality Subaru factory FPR we were able to take the guess work out with its simple operation. Preset at 43 PSI static pressure.

Plug and Play Hose Ends

  • Made from durable nylon/resin, the hose ends offer a clean, factory appearing, connection.

Hose Clamps

  • Constructed of stainless steel, these continuous band clamps offer a firm clamp load to every hose connection.

FPR Stay Bracket (not pictured)

  • Used to attach the FPR, these parts consist of: rubber insulated Stainless Steel band clamp with nylon locking nut and bolt.

FPR Vacuum Source Relocation Kit (not pictured)

  • Includes all necessary parts to relocate the vacuum hose, which further diminishes the lean spot / GR Stumble. Includes: 4mm vacuum hose, vacuum reducer tee, zip ties.
  • 60 Day Product Warranty

  • Warranty specifically parts of the kit only. If deemed failed by iA-Performance (after following our tests), then a replacement part(s) will be sent out. Warranty does not cover external items to the kit, motor, turbo, etc.

Attention Non North American Customers

It has been brought to our attention that the North American and Non North American STi have different methods of attaching the fuel hoses to the fuel rails, yet both still use quick disconnects at the firewall side. Thankfully, we cater to both markets and make kits for either application. Please reference the photo marked '?,' then select the drop down menu that correctly corresponds to your vehicle.

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This product was added to our catalog on Thursday 13 May, 2010.
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