Ensure proper installation, preferably done by a professional. Poor installation of performance parts can lead to costly issues and catastrophic engine failure. Subarus are of the fussy kind when it comes to modification, they don’t respond well if the incorrect combination of parts are used with one another and are not calibrated correctly. Turbo Subarus get a bad rep for reliability when in fact over half of failures we see are due to improper modifications and tuning.  With that said, here are 4 ways you can modify your Subaru WRX/STI reliably:

1) Take Advantage of Dyno Tuning

Dyno tuning is the only way to reliably increase your Subaru’s performance. The Subaru WRX / STI engine management system isn’t one that can handle any modifications without recalibration (tuning). In other words, the ECU strategy isn’t as “smart” as some of the new systems out there. Once anything to do with the flow of air (intake and exhaust) is modified, your Subaru is going to need a professional dyno tune. Off the shelf maps, while popular and successful on other brands of vehicles, don’t work well on Subarus and especially here at Calgary elevation and with our gas quality in Canada. 

Please do not trust your Subaru with any “tuner” that has no access to an AWD Dynamometer. Tuning can make or break your build. Doing so without a Dyno or the proper equipment is dangerous and blind. Would you trust a “dentist” that does root canals out of their home armchair? 

For truly reliable modifications to be successful - please get a professional Dyno Tune done. We have two full-time certified tuners here at Lakeview Automotive and an MD150x AWD dyno with a weather correction station. 

2) Address the Key Points of Weakness of the Factory Subaru Engine

This is a way to reliably make more power from your Subaru WRX/STI. Subaru engines especially the EJ-based variants, came with weak and poorly designed cast pistons, meaning they can only handle a slight bump up in power before serious problems occur. This is a widely known issue in the Subaru community, and the main reason we always suggest an engine health assessment test (leak down & compression test) before you purchase a Subaru WRX STI. 

To remedy this, IAG Performance offers Subaru short blocks that range in power capabilities from 550BHP to 1200 + BHP. IAG Performance, addresses the key points of weakness of the factory engine and rectifies them. They also start with a new engine block and build from there. We are an IAG Performance Dealer and certified Installer and can help you choose a Subaru engine that suits your power needs. Click here for a comprehensive guide on IAG Performance engines. 

3) Let Your Subaru Breathe Clean with an AOS (Air Oil Separator)

The AOS (air oil separator), particularly the IAG Performance AOS or the Cobb AOS (which is just a rebranded IAG part) is one of the best mods you can do to a turbo Subaru. It upgrades the PCV system by filtering out the oil vapors out of the crank case and putting the oil back into the oil sump where its much needed, leaving only clean air going back into the charged air. 

The OEM PCV circulates the crank case vapors air back into the intake, lowering the octane rating of the air/fuel mixture, this can lead to pre-ignition under load. Pre-ignition is a big killer of Subaru engines. Pre-Ignition is also a big killer of power. 

We recommend AOS on Subarus even in stock form, and especially on modified Subarus. The AOS itself is a power adder, it allows us to run more aggressive engine timing safely, because it allows for a cleaner air mixture.

Its important to note that unlike other systems the IAG Performance AOS is designed for cold weather operation. It interacts with the cooling system to insure no freeze-ups happen in cold weather. 

4) Upgrade Your Subaru's Fuel System

Lets jump to the basics of modifying any engine for more power. We try and get as much air into and through the engine via removing restrictions in the intake and exhaust, increasing pressure and flow of the forced induction system (turbo) then meeting all that air with the appropriate amount of fuel. Unfortunately, the factory Subaru fuel system is barely adequate for the stock power levels, let alone any big bumps in power. Generally, as part of any real power mod on a STI or WRX, the fuel system will need to be modified as well. This comes in the form of an upgraded fuel pump usually DW400 and ID1050x injectors. 

Feel free to come down or give us a call about upgrading and tuning your Subaru. We have a wealth of information we can share with you and can help you with professional install. Pick your desired power level and Lakeview Automotive will be happy to get you there!