TurboXS Front-Mounted Intercooler, J-Pipe, and More

After a long period of no modifications, we made a few more changes to the WRX in the fall. A TurboXS front-mounted intercooler lays the groundwork for future power increases. A TurboXS J-pipe frees up exhaust flow. On the outside of the car, we installed some STI-style mirror turn signals, and an F1-style rear brake lamp.

In many ways, the front of the car is the best possible location for the intercooler. It gets 100% cold, fresh air blasted directly onto it, so cooling efficiency is maximized. The air doesn't have to flow through any scoops or ducts and doesn't have to turn any corners.

With the older STI turbo layout, the plumbing runs for a front-mounted intercooler (FMIC) were pretty long, but on the 2015+ WRX the turbo is right at the front of the car, so the air piping isn't much longer than for the stock top-mounted intercooler. (It would be shorter if we flipped the intake manifold around so the throttle body faced forward, but that's a discussion for another time.)

The TurboXS front-mounted intercooler kit comes complete with a replacement bumper reinforcement beam/intercooler bracket structure, hard intercooler plumbing and silicone couplers to connect them all. The huge intercooler core is almost three times as large as the stock TMIC core.

See the picture of the TurboXS FMIC kit at right -- the factory intercooler core is on the left side of the photo. Note the tubular-structure replacement bumper beam, which also incorporates a tow hook/license plate mount receptacle.

Installation of the FMIC kit was not  as complicated as we feared. We did trim some of the front bumper cover to get everything to fit, but it wasn't as much as we feared, and the intercooler core sits quite nicely and discreetly behind the stock lower radiator grille opening.

To help out on the intake side, we added a Perrin silicone turbo inlet. This part replaces a problematic stock inlet made of plastic. The stock item can crack and leak, so it makes sense to replace it while we're working in that area. The Perrin item is much smoother for higher flow, plus the reinforced silicone rubber construction should hold up for a long time.

At the same time we upgraded the intercooler and the turbo inlet, we swapped in a TurboXS catted J-pipe. The J-pipe is the first exhaust component after the turbocharger, and the aftermarket version from TurboXS has larger 3" diameter plumbing, plus a high-flow catalytic converter to increase flow and power potential. In addition to the bigger diameter and higher flow, the new pipe is all fully-polished stainless steel, so it looks great.

After the new mods we put the car back on the dyno for some more custom tuning. It did much better, at 292 awhp and 281 ft-lbs to the wheels, but that was not as much as we were hoping for, and not as much as some similarly-modified customer cars that we have run on our dyno.

If this was the last stop on our modification journey, we would pull everything apart and investigate why the car wasn't making as much power as we expected, but instead we decided to push ahead to the next phase on this car. Stay tuned for more of those plans in our next post.

On the outside of the car, we installed some STI-style turn signals into the mirrors. The Subaru WRX STI comes with mirror turn signals and standard, but we installed some aftermarket items instead, for some extra pizzazz. Ours feature sequential turn-signal action, plus a white running lamp for when they are not in turn signal mode, and we think they look great. They do require a little extra wiring, because the WRX does not have factory mirror turn signals at all. Our kit includes everything you need, including OEM STI mirror caps with notches in them for the lamps. We wrapped our new mirror caps in black vinyl to match some of the black badging we've been installing around the car.

Finally, on the back of the car there is a little rectangle that looks like it should hold a lamp, but at least here in the U.S., it just has a blank piece of plastic. We fixed that by installing an F1-style brake lamp in that spot. We tied the lamp into the existing brake wiring, so everytime we hit the brakes, the center low-mounted stop lamp comes on. It even blinks when it first turns on, just like the F1 cars.

The lamp comes in a red version, which is what we chose, or a smoke version that is a little more discreet when it's not on.







Products mentioned in this blog post:

• TurboXS 2015+ WRX Front-Mounted Intercooler Kit
• TurboXS Catted J-Pipe
• Perrin Turbo Inlet
• Sequential Mirror Turn Signal Lamps
• F1-Style Rear Brake Lamp

Summer 2018 Update: Racecomp Coilovers, 19" Rota Wheels, and More

The Mach V WRX has been busy over the last half year or so, doing lots of parts delivery to our track-side store at Summit Point Raceway, plus other errands and general-use duty. We've done a good number of parts changes during that time, too.

On the cosmetic side, we did a set of JDM WRX S4-style fog lamp bezels, and some LED front turn signal indicators. The bezels maybe require a little bit of explanation. In Japan, the WRX S4 model has special front daytime running lights (DRLs) that are integrated into the fog lamp bezels. The original-equipment Subaru parts are very expensive, so we sell an aftermarket equivalent version. Actually, we sell two versions. One lights up white, just like the original JDM item; the other also switches to amber to act as a turn signal. That "switchback" model is the one we installed on our car.

The LED turn signals come in clear, smoke, or black color schemes; we chose black. They are a plug-and-play item, so installation was easy. There's an additional resistor you can clip on if you need to, to prevent super-fast flashing caused by the LEDs lower resistance, but we already have an LED-specific blinker module, so we didn't need to do that.

On the back and sides of the car, we removed the OEM chrome badging and switched to black badges. That's a pretty simple modification -- the new trunk badges just peel-and-stick to install -- but our technician did use a bunch of painters tape to line up and make sure the new badges were in the same position and were level.

The side badges attach to the plastic fender trim panels, which remove using a couple of bolts. We chose some blue STi-logo black badges for that. Yeah, the car is not an STi, but the blue matched our (custom powder-coated) STi Brembo brake calipers, and we didn't have any WRX-logo badges in stock at the time.

We changed up the wheels and suspension yet again. On the suspension front, we installed Racecomp Engineering Trophy Cup coilovers. These are an adjustable-height coilover with an excellent fixed-rate Bilstein damper. We ended up with a ride height about 2" lower than stock. The coilovers gave a ride that's a little more comfortable than the OEM STI suspension we had on the car previously, but the lower ride height and center of gravity give an amazing improvement in cornering ability.

The latest wheels are a 19x9.5" Rota KB-R. With a relatively conservative +40 offset, these wheels clear all STi Brembo brakes, and we think they look terrific. The weight is pretty good, too, at 21.25 pounds. (By way of comparison, Subaru's own factory STI 19x8.5" wheels weighs 28 pounds.) We had hoped that our 265/30R19 tires would fit without rubbing, but they JUST skim the fenders under full compression. We rolled the fenders just a bit, and so far the tire scuffing is minimal, so we can live with it.

Products mentioned in this post:

• JDM WRX S4-style fog lamp bezels
• LED front turn signal indicators
• Black fender badges
• Black trunk badges
• Racecomp Engineering coilovers
• Rota KB-R 19x9.5" wheels

Edit: I forgot to publish this post back in summer 2018, so here it is March 2019 and I've finally posted it.