Red Question Mark

For our first post on the new Common Questions segment, I thought I would tackle a fairly common request we get at the shop and one that I know very well, the Subaru WRX and STI. We’ll be covering the North American Spec 2002+ models, but with the influx of newly imported cars from Japan, some of this information will transfer over.

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So, where to start? The WRX and STI are an amazing platform to start modifying from. Subaru packs a good amount of power under the hood from factory, but as with almost every vehicle, there is room for improvement.

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TUNING

Let’s start with Tuning. Tuning is the most common thing we get asked about for these vehicles. Tuning a Subaru will help wake the vehicle up, allow you to properly install common modifications such as full turboback exhausts or cold air intakes without throwing any sort of check engine lights. For tuning of these vehicles, we recommend the COBB Accessport.

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COBB built their name in the industry by being the Subaru guys. Their Accessport is a hand-held tuner that has pre-loaded tunes for common modifications, some amazing features and also opens the door to allow for more complex modifications later on. Available for Subaru WRX’s from 2002+ and STI’s from 2004+, the Accessport is one of the quintessential Subaru must-haves. The best part about the Accessport is that is has tunes for 100% bone stock vehicles to increase horsepower, torque and driveability, as well as tunes for those more modified vehicles. The Accessport features built in gauges to monitor what your vehicle is doing, Anti-theft tunes, off-the-shelf (OTS) tunes for different octane ratings, and depending on the year of your vehicle, cool features like customization face plates,  launch control and flatfoot shifting (no need to take your foot off the accelerator pedal when you’re banging through the gears).

Intake

We are often asked about doing intakes on these vehicles. In the automotive industry, cold air intakes are one of the most commonly sold parts because they free up horsepower, torque, improve fuel economy and give a little more engine sound.  Subaru’s are bit more challenging when it comes to adding an intake system. Pretty much every air intake on the market for WRX’s or STI’s will require a tune to ensure they work properly. We highly recommend COBB’s SF air intake or AEM’s cold air intake for the 2008+ WRX and STI.

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On the intake side of things, one thing we do recommend to customers with vehicles that have some mileage on them is to look into replacing the turbo inlet hose. The factory inlet hose on the EJ205 & EJ257 engines are a combination of plastic and rubber. The rubber that connects the inlet to the turbo has a tendency of starting to fall apart after years of use, heat cycling and Canadian climates. When they rip, it can cause issues ranging from a buzz or whistle as air passes by the rubber, to more serious issues like turbo failure from pieces of rubber getting sucked into the turbocharger. We offer replacement silicone turbo inlets from companies such as Tomei, Perrin, and Mishimoto.

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Exhaust

Subaru’s have one of the most unique exhaust notes on the road. The classic Subaru rumble is iconic and is so unique that it will surely turn heads when its heard. We have a number of customers who want to get that quintessential Subaru sound without having to do any other modifications. On every WRX and STI, you can install a catback exhaust that will provide that Subaru sound, but won’t require any further modifications.  We have exhaust systems from a number of companies such as Invidia, HKS, GReddy, Perrin, & Tomei.

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Usually, we do get customers who want to get more power from their vehicles, so we recommend pairing a catback exhaust with an aftermarket downpipe and a tune. This wakes the vehicle up considerably and brings it to the infamous “Stage 2” level. There different types of downpipes available with their own advantages and disadvantages. We have downpipes available from companies like Invidia, Perrin & Grimmspeed.

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On the 2015 WRX’s Subaru changed the position of the turbocharger on the new FA20DIT motor to be a low-mounted turbo sitting off to the left side of the engine instead of their typical top mounted turbocharger. This lower mounted turbo charger spools much quicker than the typical EJ motors found in the older WRX and in the STI, but changes the style of exhaust outlet. We have downpipes for the 2015 + WRX from Invidia and COBB Tuning.

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Another piece in the exhaust system that customers often think about upgrading is the up-pipe. The up-pipe sits between the exhaust manifold and the turbocharger. On the 2002/2003 WRX’s the factory up-pipe was catted, which over time can cause restriction in the exhaust flow. Changing to an aftermarket up-pipe allows for smoother flow of the exhaust, which results in a quicker spooling turbocharger.

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Suspension

The WRX and STI’s are known for their traction and amazing handling from the factory. With the engines sitting so low in the vehicles, they come from Subaru with a very low center of gravity. Lowering these vehicles helps bring that center of gravity lower to the pavement and also helps improve the look too. There are a number of different ways to lower these vehicles.

The first option would be to install lowering springs. Lowering springs are a set drop amount progressive spring that offers a comfortable ride when driving on the streets, but progressively get harder spring rates as the vehicle is loaded up in corners such as when you are doing some spirited  driving on some back-roads or heading to the track. Lowering springs are reasonably priced, can be used with OEM shocks and struts, or can be paired with aftermarket shocks and struts to help stiffen up the ride. We have lowering springs available from companies such as H&R and Eibach, and upgraded struts and shocks from companies like Bilstein, & Koni.

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The second option to lower one your car would be a set of coilovers. Coilovers are adjustable ride height strut assemblies that allow for customization in how your vehicle sits. You can adjust ride heights, spring pre-load tensions, and depending on the features of the coilovers, adjust compression and rebound damping rates. All of this allows you do customize the suspension to the performance, style and look you require for your vehicle’s overall use. We have coilovers available from a number of suppliers such as KW Suspension, ST Suspension, HSD, and H&R.

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A commonly looked over upgrade for most vehicle’s suspension is the anti-roll bars or swaybars. Changing the diameter of the swaybars on the vehicle will change the handling characteristics. From factory Subaru build these cars with a tendency to understeer due to the weight balance of the vehicle and the AWD system. Playing around with different diameter swaybars can help mitigate the understeering by making the rear of the car come around easier, or have less resistance in the front steering. We have different diameter swaybars from Perrin, H&R & Whiteline Suspension.

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Depending on the year of your vehicle, there are some components in the suspension that can be upgraded as a preventative piece. On the 2002-2003 WRX, the rear swaybar bracke from factory was a thin flat U-shaped brace where the swaybar bushing mounts onto and where the swaybar is mounted to the frame. These thin mounts have a tendency of either twisting or actually bending when under heavy load from spirited driving or from the use of a larger diameter. The later GR/GV chassis starting in 2008 had a similar issue with the swaybar mounts. The mounts would bend under heavy useage or from the use of a larger swaybar. There are a number of different ways to help mitigate this from happening. On the older GD chassis (2002-2007), Perrin and Whiteline offer their reinforced swaybar mounts, which are made from billet aluminum to be stiffer and eliminate any unwanted flex.

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On the GV/GR chassis, Cusco and Whiteline make swaybar reinforcement brackets that attach in to OEM mounting locations to triangulate the mount to strengthen it. These come with all of Whiteline’s larger swaybars.

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I hope this little article sheds some light on some of the common modifications we do on Subaru WRX’s and STI’s. There are plenty of other modifications and topics to dive into on these vehicles, but we feel like this is a great starting point for anyone looking for some guidance.

 

If you have any questions about the information listed in this article or are looking for some guidance on your build, please contact Bryan at 403-398-9833 ext 25 or e-mail bryan@tunerworks.com