The idea for the StealthBox Intake originated from internal talks about what an ideal intake system for the 2015+ WRX should be. At GrimmSpeed, performance is key, but we also focus on other aspects. We aimed for an intake that runs quietly during normal driving but roars at wide open throttle. It also had to look good in the 2015+ WRX engine bay, not like a shoebox in the fender area. That's how the StealthBox was born. We took inspiration from the F - 117 Nighthawk for the stealthy look of the GrimmSpeed heat shield, and its performance is just as unique.
Part #: 060060
**Quick Specs**
- **+32wtq (14.3%) and +21whp (9.6%)**: Significantly boost your car's power.
- **CAD - Designed**: Ensures perfect fit with the factory turbo and ram - air scoop.
- **Low Bend Angle Aluminum Tube**: Minimizes air restriction and maximizes performance.
- **Shielded MAF Sensor Placement**: Protects the MAF from heat, making readings more accurate.
- **Made in the USA**: Manufactured in Minnesota.
**Design**
During design, we focused on MAF diameter and placement, total bend angle, filter location, and heat shield design. The MAF sensor must be in the heat shield for accurate readings. Keeping the bend angle low in the intake tube reduces restriction, and raising the filter protects it from the elements. We also used the factory ram - air scoop to feed fresh air. Our engineers created a 3D model to optimize these variables. The result is an intake with a 74 - degree bend angle and a well - placed filter. The heat shield's shape follows the factory air scoop, feeding fresh air evenly and preventing still air pockets.
We decided not to sell the intake without the heat shield. Others may cut costs at the expense of performance, but we want our customers to have the best experience, and the heat shield is crucial for the intake system.
**Materials and Fabrication**
Each intake starts with a CNC - bent and laser - cut 6061 Aluminum tube. Thicker aluminum tubing (1/8” wall thickness) has a 'thermal flywheel effect', reducing the impact of engine bay temperature changes on intake temps. Custom MAF flanges are machined from the same alloy and placed where flow is most consistent. Mounting brackets are laser - cut from 3/16” thick aluminum plate and CNC - bent for a perfect fit. Heat shields are laser - cut, CNC - bent, hand - assembled, and powder - coated for a durable wrinkle black finish.
**Performance**
Dyno and long - term road testing proved our design. We used the same pull as our J - Pipe/Downpipe test as a baseline for the 2015 WRX. After installing the intake and retuning with the same boost levels and AFRs, we saw an additional 32ftlb (14.3%) at 3000rpm and 21whp (9.6%) at 5500rpm. Tuning is required after installation for maximum 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**
Although only a small part of the intake is visible after installation, you can choose the intake tube color. The heat shield is always black wrinkle, but the tube can be black or wrinkle red.
**INSTALLATION NOTE**: Install the air filter on the intake tube carefully. Push the filter onto the tube no more than 1' before tightening the clamp to ensure the filter's velocity stack works properly.
Using the GrimmSpeed StealthBox Cold Air Intake is quite straightforward. First, make sure you have all the parts in the kit. When installing, follow the installation guide carefully. Pay special attention to installing the air filter. Push it onto the tube no more than 1' before tightening the clamp to let the velocity stack inside the filter work well. After installation, you need to tune your car to get the most out of the intake and ensure safety.
As for maintenance, check the air filter regularly. If it gets dirty, clean or replace it according to the manufacturer's instructions. Also, inspect the intake tube and heat shield for any signs of damage or wear. If you notice any issues, contact the manufacturer for advice. With proper use and maintenance, your GrimmSpeed StealthBox Cold Air Intake will keep your Subaru WRX running smoothly and powerfully.
