After news broke out about the new 2015 WRX/STI, RaceComp had get our hands on one. Fast forwards a couple of months and in March of 2014, Subaru of America graciously sent us a pre-production WRX for testing and initial development. The car lived up to the media hype even though it came with FULL snow tires and the front sway bar measured out to be a 23mm. But even so, the new chassis was night and day difference compared to the GR/GV platform. Most importantly, it allowed us start diving into the heart of our business: developing suspension components for this new exciting chassis.

As usual, we knew that a performance lowering spring, designed to be used with the stock damper is a must. Whenever there is a new product development, we always take the time to do extensive amount of R&D to ensure the end user receives the best product. We began by disassembling the OEM springs and dampers and measuring key points; spring rate, spring length, stroke, bump/droop travel at stock ride height, bump stop length, etc. Then came the most important part; analyzing the damper on a shock dyno.

With all the critical information we needed, we had a prototype set within a month. With some minor tweaks to ride height, the spring was ready to go into production.

After another month, the RaceComp Engineering 2015 WRX in Crystal White Pearl was delivered May 2014. The first impression driving off the lot reminded us of when we first got the BRZ. The OEM Dunlop gave the car more road feel, and the front sway was increased 1mm over the pre-production WRX we tested months earlier.


Naturally, this car did not stay stock for long; and with an established baseline, it was time to upgrade the suspension. With confirmation of GR/GV coilovers fitting to the new VA chassis, we equipped the car with our Tarmac 2 coilovers with 400lbs springs F&R paired with Enkei RPF-1 in 18x9.5 +45 with 265/35/18 Michelin Pilot Supersports. The Tarmac 2s and new wheels and tires helped the car feel more refined yet keeping the firm sportiness of the new chassis. We knew this only the beginning to the many different stages of the car.

Although the car felt solid, it was still exhibiting a bit of understeer at the limit. With the new VA and old GR chassis sharing similar suspension parts, we added our RCE 25.5mm hallow rear sway bar in place of the OEM 20mm to help the car stay more neutral.

Next, we wanted to tackle the brakes. With intentions of tracking the car, we knew the OEM brakes would not be up to the task. We went the same route as with the BRZ and installed the Essex Designed AP Racing Competition front kit.

The kit utilizes AP Racing 4 piston calipers along with 325x32mm J-hook 2 piece rotors allowing us to shave 24lbs off the front axle! The less unsprung mass was felt immediately with an initial test drive. The kit not only provides less weight, but more cooling and improved pad and rotor wear and most importantly, a more solid pedal feel.

Unfortunately the brakes did not clear either set of wheels we had on hand and made the choice to not install these at the time.

With any new chassis, we always like to test as many different suspension setups as possible. With the fall months coming, we decided it was a good time to switch it up and opted for the Ohlins Road & Track coilovers.

With new suspension comes new wheels and tires, specifically Prodrive GC-014i 19x8.5 +43 coupled with 255/35/18 Michelin Pilot Supersports.

The Car exhibited excellent chassis control but we found that for MD roads, there was not enough amount of bump or droop travel, and that’s with 600lbs front and 500lbs rear spring rates.

Fast forward to 2015 and it was time for a new suspension set up. This time, we installed our newly released Tarmac 3 competition 3-way coilovers.
These dampers offer your typical low speed compression and rebound adjustments while adding in the ability to fine tune the dampers with high speed compression.

The Innovative hybrid monotube and twintube construction features a piggyback canister containing a divider piston for compression valving. Rather than relying on spring preloaded needle valve and deflection disks on the compression side, non-preloaded valves with distinct metered orifices allow for more consistent fluid flow through the valve, which means a consistent difference is felt for each click of adjustment.

We opted for a 600lbs front and 550lbs rear spring rates coupled with our RCE Forged Lowering camber plates.

While the Essex Designed AP kit was great, we’ve always wanted a front and rear big brake kit. Not only were these available as a front and rear kit, but they cleared our wheels as well.

We swapped the Essex kit for the StopTech Performance Sport Trophy Kit. This Trophy kit features a 4 piston front with 325x32mm slotted rotors and a 2 piston rear with 345x28mm rear rotors. Street pads are Endless MX-72 and track pads are Pagid Yellows.

The new suspension and brakes wouldn’t be complete without a new set of wheels and tires. We added the lightweight WedsSport TC105N in 18x9.5 +35 with super sticky 245/40/18 Pirelli P Zero Trofeo Rs.

Up until this point, the only power mod is the Cobb accessport. With the popularity of the 2015’s growing at a staggering rate, we decided to venture outside of our norm and develop the new RCE Clubsport exhaust system. The RCE Clubsport exhaust features 3” piping that splits into 2.25” at the y-pipes and matted to four 3.5” RCE laser etched tips producing a nice throaty but not overly loud aggressive tone.

To give the car as much flow as possible, we’ve paired the RCE clubsport exhaust with the Invidia catless J-pipe. For map support, we went to BrenTuning who provided us with one of his custom e-tune maps.

At this point, the car looked and handled great but we wanted a little more edge and road feel throughout the car. As some may know, we are in the process of developing new bushings for the new VA chassis and installed them on the WRX. New front control arm and rear trailing arm bushings were installed as well as rear sub frame inserts (not pictured).

With a scheduled track day coming soon, we wanted to be on the cautious side and installed a Perrin Performance oil cooler to ensure we wouldn’t have any overheating issues to make the most of the shakedown test.

With all the new bushings installed, a new alignment was a must! With the RCE Forged Lowering plates, we set front camber to a nice -3 degrees with rear camber settling in at -2.4 degrees. Zero toe front and rear.

The last prep for the initial shake down test was the get the car dyno tuned to see what actual numbers the car is putting out. Prior to the protune, we also installed an ETS intake. The final numbers were not as high as others running the same modifications but the car pulled very strong all the way to redline.

After the initial shake down, we knew that a wider tire was a must. Knowing how good the Pirelli Trofeo Rs are, we opted to get the same tire but in a 265/35/18….on some new wheels too. These beefy tires are going on a set of ultra-lightweight TWS T-66F in 18x9.5 +40.

With the handling, braking and engine all covered, it was time add some new goodies to really bring this car together. As many know, the OEM seats make you feel as if you are driving a bus. To combat this, we installed a set of Recaro Sportster CS’ in alcantara. With the seating position taken care of, next was onto the steering wheel. As with the BRZ build, we went to JPM coachworks who provided us with a alcantara wrapped steering wheel.

Next up, installing the new RCE Street Camber Plates for additional caster!

Originally posted on IWSTI.