Does the StealthBox intake for VA Subaru WRX models need a tune?

Yes. GrimmSpeed lists the StealthBox intake for VA Subaru WRX models as Tuning Required and not compatible with the factory tune or any off-the-shelf map. Plan on a custom tune at installation, both to keep the FA20DIT safe and to collect the gains GrimmSpeed measured.

How much power does the GrimmSpeed StealthBox add?

On a 2015 WRX retuned at matched boost and air-fuel ratios, GrimmSpeed recorded gains of 32 ft-lb at 3000 rpm and 21 whp at 5500 rpm, or 14.3 and 9.6 percent. That dyno read low, with a stock baseline of 174 whp, so gains matter more than peaks.

Can the intake be run without the heat shield?

No. GrimmSpeed chose not to sell the StealthBox without its heat shield, because the shield keeps engine bay heat off the filter and MAF sensor and channels air from the factory scoop. Running the tube alone would undo the design work behind the intake.

Is the StealthBox louder than the factory airbox?

Yes, under load. GrimmSpeed set out to make an intake that stays quiet during normal driving and becomes noticeably louder at wide open throttle, so the extra induction sound mainly appears when the turbo is working hard rather than at highway cruise.

Does the StealthBox keep the factory air scoop?

Yes. GrimmSpeed testing showed the factory ram air scoop feeds the filter with air that would otherwise sit stagnant in front of the fender, so the StealthBox heat shield is shaped to mate with that scoop and with the factory turbo inlet connection.

Description

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Description

GrimmSpeed StealthBox Cold Air Intake for VA Subaru WRX

GrimmSpeed’s StealthBox cold air intake for VA Subaru WRX models runs a CNC-bent 6061 aluminum tube with a 1/8 inch wall and only 74 degrees of total bend from the fender-mounted filter to the FA20DIT turbo, with the MAF sensor sealed inside an angular heat shield modeled on the F-117 Nighthawk. It belongs on a WRX that already has, or is about to get, a custom tune: GrimmSpeed states it is not compatible with the factory calibration or any off-the-shelf map.

Development and Testing

GrimmSpeed modeled the intake path and fender area in 3D, balancing MAF diameter and placement, total bend angle, filter height and shield shape. Because the factory ram air scoop proved important, the shield follows its outline and promotes swirl to avoid dead air on the cold side. Six months of Minnesota winter and spring driving then confirmed the dyno results.

Features

MAF flange placed on the straight nearest the filter, where GrimmSpeed measured the most consistent flow
Thick aluminum wall adds thermal mass that damps rapid swings in engine bay temperature
Filter raised clear of road spray and tucked inside the fender
Heat shield laser cut, CNC bent and assembled by hand
Made in the USA

Specifications

Tube Material: 6061 aluminum, CNC bent and laser cut
Tube Wall Thickness: 1/8 inch
Total Bend Angle: 74 degrees
Mounting Brackets: 3/16 inch aluminum plate
MAF Harness Extension: 12 inch

What’s Included

CNC bent intake tube with MAF flange
GrimmSpeed high-flow dry air filter
Aluminum heat shield
MAF harness extension (12 inch)
Silicone hump coupler
Stainless steel worm gear clamps (x3)
Rubber gasket material, cut to length (x3)
MAF sensor machine screws (x2)

Applications

Subaru WRX: VA | 2015-2021 | 2.0L FA20DIT

Notes

Tuning required: GrimmSpeed lists this intake for VA Subaru WRX models as not compatible with the factory tune or any off-the-shelf maps
Dyno figures come from a 2015 WRX retuned after installation at the same boost and air-fuel ratios as its baseline pull, on a dyno that read 174 whp for a stock car, so they are not bolt-on results
Also available as part of the GrimmSpeed Stage 1 Power Package for VA Subaru WRX

Frequently Asked Questions

Does the StealthBox intake for VA Subaru WRX models need a tune? Yes. GrimmSpeed lists the StealthBox intake for VA Subaru WRX models as Tuning Required and not compatible with the factory tune or any off-the-shelf map. Plan on a custom tune at installation, both to keep the FA20DIT safe and to collect the gains GrimmSpeed measured.
How much power does the GrimmSpeed StealthBox add? On a 2015 WRX retuned at matched boost and air-fuel ratios, GrimmSpeed recorded gains of 32 ft-lb at 3000 rpm and 21 whp at 5500 rpm, or 14.3 and 9.6 percent. That dyno read low, with a stock baseline of 174 whp, so gains matter more than peaks.
Can the intake be run without the heat shield? No. GrimmSpeed chose not to sell the StealthBox without its heat shield, because the shield keeps engine bay heat off the filter and MAF sensor and channels air from the factory scoop. Running the tube alone would undo the design work behind the intake.
Is the StealthBox louder than the factory airbox? Yes, under load. GrimmSpeed set out to make an intake that stays quiet during normal driving and becomes noticeably louder at wide open throttle, so the extra induction sound mainly appears when the turbo is working hard rather than at highway cruise.
Does the StealthBox keep the factory air scoop? Yes. GrimmSpeed testing showed the factory ram air scoop feeds the filter with air that would otherwise sit stagnant in front of the fender, so the StealthBox heat shield is shaped to mate with that scoop and with the factory turbo inlet connection.

About GrimmSpeed

GrimmSpeed began in 2006 in a single-stall garage in Maplewood, Minnesota, porting and polishing Subaru manifolds. After building parts for several other makes, the company narrowed its focus back to Subaru, and its range now covers intercoolers, charge pipes, intakes, bypass valves, headers, up-pipes, catback exhausts, turbochargers, brake caliper kits, drivetrain mounts and titanium engine bay parts for the WRX, STI, Forester XT, Legacy GT, Ascent and BRZ, along with the Toyota 86 and GR86. GrimmSpeed engineers and manufactures as much of that range as it can in-house, and its front mount intercoolers are welded and inspected by hand in the USA.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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GrimmSpeed StealthBox Cold Air Intake for VA Subaru WRX

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GrimmSpeed StealthBox Cold Air Intake for VA Subaru WRX

Development and Testing

Features

Specifications

What’s Included

Applications

Notes

Frequently Asked Questions

About GrimmSpeed

Reviews