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GrimmSpeed

GrimmSpeed StealthBox Cold Air Intakes - Fits Subaru WRX 2015-2018

GrimmSpeed StealthBox Cold Air Intakes - Fits Subaru WRX 2015-2018

SKU:GRIM-060060

Regular price $402.99 USD
Regular price Sale price $402.99 USD
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Inspiration for the StealthBox Intake came from internal discussions about what we wanted from an intake system for the 2015+ WRX. Of course performance is the highest priority, but at GrimmSpeed so much more than that goes into a product. We wanted an intake that purred quietly under normal driving circumstances, but would roar at wide open throttle. We wanted an intake that looked at home in the well-sported 2015+ WRX engine bay instead of a shoebox stuffed into the fender area. From here, the SteathBox was born. We took the concept one step further and referenced the F-117 Nighthawk as inspiration for the stealthy look of the GrimmSpeed heat shield. It should come as no surprise that the performance it packs is equally unique.

** INSTALLATION NOTE - Take care to install the air filter onto the intake tube properly. Push the filter onto the tube no more than 1" before tightening the clamp. This will ensure that the velocity stack within the filter is allowed to function properly! **


Quick Specs

  • +32wtq (14.3%) and +21whp (9.6%)
  • Designed in CAD - Perfect mating with the factory turbo and ram-air scoop
  • Low bend angle aluminum tube - Minimize restriction and maximize performance
  • Shielded MAF sensor placement - Protects MAF from heat, which increases accuracy of readings
  • Made in the USA - Manufactured right here in Minnesota

Design

 

MAF diameter and placement, total bend angle, filter location, and heat shield design were the primary variables during the design phase. To ensure accurate readings, unaffected by the intense heat of the engine bay, MAF sensor placement absolutely must be within the heat shield. To minimize restriction, it was important to keep the total bend angle in the intake tube as low as possible, but still raise the filter location away from the ground to protect it from the elements. Lastly, testing showed the importance of utilizing the factory ram air scoop to feed the otherwise stagnant air in front of the fender.


Our engineers created a 3D model of the intake system and fender area in order to optimize each of these variables. The result is an intake with a total bend angle of 74 degrees, and a filter that is placed neatly within the fender, such that it offers protection from the elements without being unnecessarily exposed to the heat of the engine bay. Lastly, the shape of the heat shield follows that of the factory air scoop, feeds the filter with fresh air evenly and promotes swirl which prevents pockets of motionless air on the cold side of the shield.

We have made the decision not to sell the intake without the heat shield. It seems that others have done this to hit a lower price point at the cost of performance. We'd prefer that everybody using a GrimmSpeed StealthBox Intake have the best possible experience and the use of the heat shield is critical to the function of the intake system.

Materials and Fabrication

Each intake begins with a CNC bent and laser cut 6061 Aluminum tube. Contrary to popular belief, particularly from those producing composite intakes, we found that the increased thermal mass of using thicker aluminum tubing (1/8” wall thickness) kept the intake from being vulnerable to rapid temperature change. This is called the ‘thermal flywheel effect’ and will keep the rapidly fluctuating temperatures inside your engine bay from affecting intake temps as drastically.

Custom MAF flanges are machined from the same 6061 alloy and are placed on the straight nearest the filter, where we observed the most consistent cross-sectional flow. Mounting brackets are laser cut from 3/16” thick aluminum plate and CNC bent for perfect and repeatable fitment. Finally, heat shields are laser cut, CNC bent and hand assembled before going to powdercoating for a durable wrinkle black finish.

Performance

Dyno testing and long-term road testing are where all of this theory meets reality. Knowing that the same application of these design techniques resulted in intakes that performed extremely well on both the BRZ/FR-S and the 08-14 WRX/STI, we were confident in our chosen configuration. Dyno testing and tuning verified the intakes ability to make power and 6mos of road testing through winter/spring in Minnesota confirmed real-world performance.

We chose to use the exact same pull that tested the performance of our J-Pipe/Downpipe as the baseline for our 2015 WRX. This proves that our baseline is not somehow artificially low. We then installed the intake and had the car retuned using the same boost levels and air fuel ratios (AFRs). This is an extremely important part of evaluating an intake system. If the before and after results aren’t showing the same boost levels or AFRs, performance increases can be attributed to tuning rather than to the performance of the intake hardware itself. The chart below shows the before and after just described with both boost and AFR plotted along with whp and wtq. It should be noted that the stock baseline for this car was 174whp, so this particular dyno reads very low.



The GrimmSpeed intake produced an additional 32ftlb (14.3%) at 3000rpm and 21whp (9.6%) at 5500rpm, with healthy gains all the way across both curves. As mentioned before, the AFR and Boost curves are also included to demonstrate that the gains shown are from the intake alone, not the manipulation of other variables.

As with any intake for the 2015+ WRX, tuning is required after installation to maximize gains and safety.

GrimmSpeed Stealthbox Intake Kit Includes

  • 1x CNC bent intake tube w/ MAF flange
  • 1x GrimmSpeed high-flow air filter
  • 1x Aluminum heat shield
  • 1x 12" MAF harness extension
  • 1x Silicon hump coupler
  • 3x Stainless steel worm gear clamp
  • 3x Rubber gasket material cut-to-length
  • 2x MAF sensor machine screws

Options

While only a very small portion of the intake is visible after installation (nearest the turbo), we still decided to offer a color choice for the intake tube. The heat shield will always be our stealthy black wrinkle, but the tube can be either a matching black, or a wrinkle red.

Fitments

  • 2015-2016 Subaru WRX

** INSTALLATION NOTE - Take care to install the air filter onto the intake tube properly. Push the filter onto the tube no more than 1" before tightening the clamp. This will ensure that the velocity stack within the filter is allowed to function properly! **

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Warranty Information

RalliTEK BRANDED PRODUCTS LIFETIME WARRANTY

RalliTEK branded products are warranted to the original owner against manufacturing defects in materials and workmanship for the lifetime of the product.

If a RalliTEK branded product covered by this warranty fails due to a manufacturing defect we will repair the product, without charge, or replace it at our discretion. This policy covers only original, unaltered, and unmodified materials and workmanship. This warranty does not cover damage caused by incorrect installation, accident, improper care, negligence, normal wear and tear, or the natural breakdown of colors and materials over extended time and use. Damage not covered under warranty may be repaired for a reasonable rate and a fee will be charged for return shipping.

No payment or reimbursement shall be made for installation, removal, transportation, or other charges. The remedies outlined in this instrument are exclusive and the liability of RalliTEK with respect to any sale shall not exceed the price of the product on which the liability is based.

For warranty evaluation, please contact RalliTEK Customer Service at (503) 619.0055 or info@rallitek.com to obtain a return authorization. Once this step has been completed, your product must be returned directly to the RalliTEK Warranty Department, 13339 NE Airport Way, Suite 500, Portland, OR 97230. All shipping to the Warranty Department must be pre-paid and insured. RalliTEK will not be liable for damaged or lost inbound packages.

      NOTE: This warranty is only available within the United States or Canada

  • This warranty gives you specific legal rights; you may have other rights, which vary from state to state.
  • This warranty does not cover products sold by RalliTEK that are not RalliTEK branded products.

The RalliTEK website sells discontinued, special markup, and slightly blemished products at significant discounts as 'factory seconds' products. This warranty does not automatically cover products purchased as factory seconds. RalliTEK reserves the right to determine if any warranty applies on a case-by-case basis for factory second parts. If approved, the RalliTEK Warranty Department may repair factory second products for a reasonable charge and applicable shipping charges.

MANUFACTURER WARRANTIES (FOR NON-RALLITEK BRANDED PRODUCTS)

Non-RalliTEK branded products do not have any written or implied warranties. Products on RalliTEK.com are sold with the warranty applied directly from the manufacturer. The customer must contact the product brand manufacturer for any warranty details. All products sold by RalliTEK are intended for off-road and/or race use only, as suggested by the manufacturer, and should be installed and set up by professional service centers only. RalliTEK is not responsible for any product failure or failure due to installation. Should a warranty claim arise, the customer and the manufacturer will handle all warranty issues directly.

There is no warranty on high-performance or race-related parts due to the nature of usage.

No payment or reimbursement shall be made for installation, removal, transportation, or other charges. The remedies outlined in this instrument are exclusive and the liability of RalliTEK with respect to any sale shall not exceed the price of the product on which the liability is based.

EXCEPT AS STATED OTHERWISE IN THIS WARRANTY, RalliTEK MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you. RalliTEK shall not, in any case, be liable for special, incidental, consequential, indirect, or other similar damages arising from any breach of these warranties even if RalliTEK or its agent has been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you. This warranty is governed by the laws of the State of Oregon.

Installation Instructions

Applications

Subaru Impreza WRX Base - 2015
Subaru Impreza WRX Base - 2016
Subaru Impreza WRX Base - 2017
Subaru Impreza WRX Base - 2018