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Short Ram Big MAF Intake System Red for 2002-07 WRX/STI


30 Minutes

Part Number
PSP-INT-221RD = Red

Was: $252.00
Sale: $226.80
Save: 10%
Save: $25.20


Short Ram BIGMAF Intake System

Increase horsepower and style under your hood.The PERRIN Performance BigMAF intake system uses an enlarged MAF housing to allow tuners to use the factory MAF sensor for tuning Subarus with large turbos.

ECU Tuning

The BigMAF intake system requires ECU re-calibration in order to run properly on your vehicle. This BigMaf is designed to do two things:

Allow your ECU to accurately measure airflow above and beyond what the stock intake can measure.
It is sized specifically to offset the use of 800cc fuel injectors.

» Read more on the compatibility tab above.

Precision Construction

Our intakes are constructed from aluminum tubing which is precision CNC mandrel bent for consistent and perfect fitting parts. Our MAF sensor bung is CNC machined for perfect fit and alignment of MAF sensor to intake. This is crucial for proper air fuel ratios and ECU engine management.


With a PERRIN intake system your car will make a throaty, deep tone on throttle that is undeniably modified. You will be able to hear your turbo spooling and hear your blow off valve every time it opens. Even the stock one.

T-Bolt Clamps

PERRIN short ram intake systems use high tech T-bolt clamps. Our high end clamps offer maximum holding power and have a built in liner so they will not damage silicone couplers. Each clamp is laser etched with the PERRIN logo.


This PERRIN Performance product features a durable powder coat finish. PERRIN powder coating is available for the Short Ram Big MAF Intake in red and is accented with a wrinkled texture finish.

Filter Tech

PERRIN Performance intake filter elements use open cell foam to capture dust and dirt. Washable and reusable, PERRIN foam filter elements can last the life of your vehicle. Foam filter elements offer superior performance for turbo charged vehicles with minimal airflow restriction and amazing dust holding capacity. Increasing the longevity of your turbo.
» Learn More

5 Year Warranty

PERRIN Performance warrants to the original purchaser that all PERRIN products will be free from defects in material and workmanship within a sixty (60) month period from the date of purchase. *Some exclusions apply
» Read Full Warranty

Off Road Use Only

This product is legal in California only for racing vehicles which may never be used upon a highway. Check your local and federal laws prior to installation.
» Learn More


Download Instructions

Warranty Details

This product features a 5 year warranty Read Full Warranty

Tech Department


Compatibility Detail


2002-2007 WRX Yes
2004-2007 STI Yes
2004-2008 Forester XT Yes

ECU Recalibration Required

The BigMAF Intake system requires an ECU recalibration in order to be installed and run properly on your vehicle. The BigMAF Intake system is intended for use on Subarus which are using aftermarket turbo chargers that can "outflow" the stock intake system.

The BigMAF Intake system is designed to do two things:

1. Allow your ECU to accurately measure airflow above and beyond what the stock intake can measure. This wider range of MAF readings allow for more resolution in the fuel and timing mapping so the engine can be safely tuned for Wheel Horsepower ratings up to 500WHP.

2. It is sized specifically to offset the use of 800cc fuel injectors. When tuning your ECU, this scaling effect will allow other settings to remain the same as though you were using the stock injector size. This lets other internal parameters in the ECU work better so the car runs smoother.

Tuning Guidelines

One method of tuning the BigMAF Intake system is to not change the ECU's injector size to 800cc(or your actual injector size). The increased size of the BigMAF housing will offset the larger sized injectors. Leave the scaling and injector size at stock settings with only minor changes to the injector size setting to get the idle and light throttle fuel corrections set. Then start with tuning the MAF curve to hit your AFR Targets. Also keep in mind that this will effect engine load by dropping it down about 25% which means you will need to rescale the timing tables and dynamic advance tables.

The other method involves changing the injector size to 800cc(or your actual injector size), rescaling the entire MAF curve by adding roughly 20% across the whole thing. This is just a starting point and requires lots of time dialing in the entire curve to ensure low RPM drivability is good, as well as full throttle fueling is correct. This method takes longer to dial in, but allows for other timing maps to be left along as the engine load isn't offset.


For addition questions or help with tuning your BigMAF Intake system please contact PERRIN Tech

In The Box

In The Box

(1) PERRIN Big Maf adapter
(1) PERRIN Foam Air Filter
(1) PERRIN Silicone Coupler
All necessary hardware
(1) PERRIN License Plate Frame


Shipping Information

  • Item Requires Shipping
  • 3.0 lbs.
  • W8.0000” x H8.0000” x L20.0000”
  • This item ships in its own box.