SPT - PROVING THE PARTS
THE SUBARU PERFORMANCE TUNING TEAM PUTS PARTS TO THE TEST TO PROVE THEIR WORTH PRIOR
TO RELEASE.
 Impreza WRX Performance Exhaust System. |
 SPT High Flow Air Intake for Legacy 2.5 GT. |
 SPT parts are tested for quality.] |
Subaru of America, Inc. offers performance parts for its vehicles through its proprietary Subaru Performance Tuning (SPT) division. Demanding in its choices of componentry, manufacturer and quality control, SPT ensures fit as well as performance prior to selling parts to customers.
ADDED POWER TIMES TWO
The availability of two sets of performance parts prompted Drive Performance to spend some time with SPT engineers to understand better the sort of testing SPT does. The parts under review included high-flow air intakes, heat shields and cat-back exhaust systems for Impreza WRX, Impreza WRX STI and Legacy 2.5 GT models. The cat-back exhaust systems for the WRX STI and WRX are available through SPT, while the high-flow air intakes and heat shields will be announced soon. The 2.5 GT cat-back exhaust system is still being evaluated.
The systems are designed to replace the stock intake and exhaust components without having to modify either the engine bay or the exhaust hangers. Step-by-step instructions are included, along with additional parts needed for installation.
 Garrick Goh, Project Engineering Manager for SPT. |
Although development may take one of a number of different paths before earning an SPT badge or logo, the parts face strict controls to ensure quality build within tolerances set by Subaru and Fuji engineers. When outsourcing parts, SPT inspects manufacturing sites for sufficient space and personnel. If the part is going to wear the SPT logo, it must be manufactured to Subaru quality-control standards, which must be in place.
The parts manufacturers run their own tests, of course, and they report the results to Subaru. SPT engineers test the parts as well to confirm those results.
DYNA-MO
Such was the case for the two intake and exhaust systems. With the help of Easy Street’s technicians, SPT personnel performed one round of testing at AWD Performance and Tuning in Palmdale, California. Utilizing AWD’s Dynapack AWD dynamometer, the performance levels of the vehicles were measured with both original equipment and the new parts. Testing with the factory parts gave the crew a base line for measuring increases in horsepower and torque. Testing was performed on a 2006 Legacy 2.5 GT Sedan with an automatic transmission, a 2006 Impreza WRX with a manual five-speed transmission and a 2006 Impreza WRX STI with its six-speed manual.
Both the Legacy and the Impreza systems delivered significant results, which, at press time, were yet to be confirmed by subsequent tests in other facilities. During the California tests, exhaust systems were found to have a larger impact on increasing horsepower than the intakes. Also, the heat shields make major contributions to maintaining a flow of cooler intake air, which results in improved engine performance.
Added benefits of these SPT intake and exhaust systems go beyond improved performance. The parts are covered by the Limited Warranty for Genuine Subaru Replacement Parts and Accessories. This warranty begins on the day the part is purchased and lasts for one year, regardless of mileage, or for the period of coverage remaining for the part under the Subaru New Car Limited Warranties, whichever is longer. See your Subaru dealer for details.
 Original air intake for the WRX. |
 SPT High Flow Air Intake installed in the WRX. |
 The WRX mounted on the dyno for testing. |
 Dyno data analysis. |
These tested SPT parts give you improved performance, proper fit, easy installation, quality workmanship and the added value of not disturbing warranty coverage. Take a look!
WATCH YOUR AIR-FUEL MIX
If you install the SPT High Flow Air Intake system and want to measure the results, be sure the air-fuel mix resets to original specifications prior to testing. Especially if the SPT setup is dynoed first, neglecting to reset the control unit will result in an air-fuel mixture that’s too lean. That will skew dynamometer results for the base line too high, and the comparison will not be apples-to-apples. Disconnect the battery so the control unit resets to ensure proper calculations from the air mass sensor input.
Remember, too, that dynamometers vary in their readings – from dyno to dyno. Other variances occur due to changes in the weather – pressure, humidity, temperature and so on. Use the same dynamometer for base-line (original equipment) measurements and for runs with the SPT parts installed, and make the tests as close together as possible for the most accurate results.