Subdriven | The Subaru Enthuisast Website

When longtime Volvo aftermarket specialist IPD went looking for new markets to expand its business, they discovered that many of their Volvo customers also drove Subarus. Further research proved their suspicions correct, that the typical Subaru buyer wasn’t that much different than the typical Volvo buyer. The fact that Subies outnumber their Swedish counterparts nearly ten to one clinched the decision for IPD.

Adding another product line is always a challenge for a company. The best way to determine if a product is worth carrying is to try it, so Chris Delano at IPD picked up a 2003 WRX to use as a development car. Wanting to offer a similar lineup of products as their Volvo division, they started with performance upgrades and came up with the Australian company APS.

The 2003 WRX test mule was working well, up until Chris rolled the car down an embankment on a hilly country road. The accident proved that Subarus and Volvos are more alike than expected, as Chris escaped the serious accident relatively unharmed, spending only a couple days in the hospital for observation. A little shaken by the incident, but not deterred, Chris set about replacing the wrecked WRX with a 2004 model to continue the development. The results so far are the car you see here.

IPD chose the Australian tuner APS as their primary source for performance enhancements. Anyone familiar with turbo engines knows that the key to making more power is engine breathing: getting more in and out of the engine more efficiently. APS offers solutions for every leg of the journey tip to tailpipe.

Starting at the front, air enters the cold air intake system, which flows more freely than the factory airbox it replaces. Excessive engine compartment heat is shielded from the open-element filter, keeping the intake temperatures down for added power. From here the intake flows to the turbo inlet pipe, or “up-pipe” with its integrated flex joint, before entering the SR30 ceramic ball bearing turbocharger.

According to IPD, the SR30 turbo flows approximately 31% more than the factory charger, and allows for a maximum of 26 psi of boost versus the stock turbo’s limit of 18 psi. While larger displacement turbochargers allow for greater boost and ultimately greater horsepower, the downside is increased lag time. One way to reduce the lag is by using ceramic ball bearings instead of conventional metal bearings. The ceramic bearings have a lower coefficient of friction and allow for better response and less boost lag.

Once compressed by the turbo, the intake charge passes through the upgraded top-mount intercooler. The APS intercooler has a core almost 2.6 times larger than stock, with only a 1.6 psi pressure drop to boot. Airflow to the intercooler is optimized by the hood scoop splitter. Excess boost is managed by APS’s dual-vent blow-off valve.

On the other side of the turbocharger, the spent gases exit through a cast turbine outlet before traveling downstream through the stainless steel exhaust system, measuring a full three inches in diameter. What comes out of the five-inch polished tip is an exhaust note that sounds both rich and purposeful.

All of these upgrades sound great, but they are useless without two other elements factored in: fuel and management. All of that additional air the turbo pumps must be matched by a proportionate amount of gasoline. To ensure the engine isn’t starved for fuel, the factory pump is replaced with a high-capacity unit from Wolboro. The additional flow is controlled by a rising-rate fuel pressure regulator from AEM.

Keeping track of all the critical functions is a Unichip engine management system. The Unichip system is a piggy-back ECU with a “plug-and-play” harness, maintaining the integrity of the factory electrical system. IPD is able to program two different map sets into this system, allowing the driver to choose a setting that is appropriate for different fuel qualities and driving conditions. For instance, one map can be a street setting for premium pump gas, while the second setting can be optimized for 100-octane race fuel. The driver can select the appropriate setting for a given situation by toggling a switch under the dashboard.

With all of these upgrades, IPD’s WRX went from its stock 227 horsepower to a more exciting 320 horses. Needless to say, the difference is immediately noticeable. The 0-60 time dropped a full second and a half, from 5.4 to 3.9 seconds. More power can be squeezed from these components, but IPD has chosen to tune its customers cars in the 290-320 horsepower range for streetability and durability. In their opinion, taking it much beyond 320 could jeopardize the reliability of the engine and other drivetrain components. At this point the owner would need to upgrade transmission components, the clutch and fuel injectors as a minimum.

Putting almost 100 additional ponies to the ground required some chassis upgrades. The factory suspension was replaced with a Fulcrum Formulae One adjustable coilover setup that uses adjustable Koni shock inserts. This combination allows for ride height adjustment, corner balancing, and adjustable rebound control for a totally tailored appearance and ride. To control body lean and allow for further fine-tuning of the chassis, IPD developed their own swaybars for the Subaru. The front bar is 22 mm in diameter, while the rear bar is adjustable, and is available in three different diameters: 19, 21 or 23 mm. Adding stiffness to the chassis is a pair of strut braces from Alutec, one at the front and one at the rear.

Properly connecting the chassis to the road is critical to a car’s performance. IPD chose a set of BBS RGR alloy wheels in 17-inch diameter for their WRX. The RGR is a one-piece forged design made in Japan, where the company produces all of its forged wheels. With its classic design, low weight, and incredible strength, this wheel is an excellent choice for aesthetic reasons as well as its functionality. Wrapping the alloy is a set of Dunlop FM901P high-performance tires, sized at 225/45-17.

Chris chose to leave the appearance of his Subaru relatively untouched. The few changes that were made are subtle. The standard WRX hood scoop was replaced with the larger one from the STi. Inside, a Momo Race aluminum shift knob sits in place of the generic factory-issued item, and it is now connected to a short shifter from IPD that reduces the throw by about 40% and knob height by 2 inches. A boost gauge from the Subaru accessory catalog allows the driver to keep tabs on the workings of the engine, without sacrificing the appearance of the interior. The last concession to style is an all-around 36% window tint from Mobile Window Tint of Portland Oregon.

By building a company project car, IPD has not only learned more about the Subaru product line, they have also learned a lot more about the people who buy them and modify them. Their line of products will continue to expand, building on the success of the performance upgrades. In fact, the company will distribute it first-ever Subaru-exclusive catalog this summer. You can visit their website for more details.

As for Chris, he is having a great time with the WRX, and thoroughly enjoys his drive to and from work every day. He is continuously amazed at the capabilities of his car and the potential for customers to upgrade their own cars specifically to their tastes. Now, if he can just keep this one on the road, everyone will be happy.