Project Gen3 STi – Fueling and Intercooling


Subaru Impreza WRX STi Crawford FMIC pipe routingJust an example of how perfectly the piping in this kit fits. This is the driver side and as you can see the pipe routes around the headlight washer fluid fill and up to the throttle body. In this picture the pipe was attached to the TB and tightened just to show how precisely it meets with the outlet of the FMIC. 

All joking aside the fit and finish of the FMIC and associated piping is first rate! Most kits route the turbo outlet straight outward which increases piping length and also means that the cold side of the charge pipes has to route back to the throttle body OVER and near the turbo. The Crawford unit uses the OEM 90 degree coupler to route the compressor discharge upward in to a 90 degree aluminum bend and then turns downward in front of the engine. The intercooler piping is mandrel bent, seam welded and then ground flat, bead rolled and then ceramic coated. It is such a joy to see the extra step of grinding the welds flat and finishing the piping before coating. While welds can be an art form of themselves, unless you can see proper color and the material is left raw I prefer smooth piping. With the routing of the hot side pipe nothing needs to be moved or relocated. The plastic lip from the splash guard needs to be trimmed by about 1 inch or you could leave it bent over, but that is it. Once the hot side enters the IC it exits through a gentle radius 90 degree towards the passenger side headlight opening. The pipe that connects to the throttle body is one piece from there and it bends around the battery and down through the front next to the headlight. This offers shorter routing than moving the battery or washer fluid reservoir like other kits do. They primarily do that to use larger piping in their kits and with our power goals I am perfectly happy with 2″ piping all the way through and we hope to show with our upgraded turbo dyno charts that we are able to preserve area under the curve and keep the power band where Subaru intended it to be without the fall off up top.

I have never worked with a kit that fit as god as the Crawford unit does and the quality is unmatched. A unique feature is that the Crawford FMIC kit eliminates the factory bypass valve. While this is a topic of controversy and is something that even our own Sarah Forst talked about in her Ask Sarah article. The logic is that there does not appear to be quantified data that shows that putting the compressor in to surge due to the backup of the charge air diminishes turbo life. In fact the largest position people seem to take is that a recirculated BPV quiets things up and eliminates those rally car type chuffing and hissing noises associated with cars that do not release the charge air once the throttle plate slams closed. Certainly there are other positions relative to turbo response however we installed the kit as provided without a BPV and chose to plug the OEM fitting in the intake tube with an expansion fitting.

BPV recirc blockoff STi

We used this expansion fitting to block off the recirc port on the OEM intake. Crawford provides a very nice CNC aluminum plug that fits within the factory hose. Because we removed the hose completely we used this method. Hell that hose must weight at LEAST 3 oz. and we are ALL about weight reduction. 

The instructions with the Crawford kit are also first rate as are the silicone couplers and T-bolt clamps provided. About the only thing one could argue about was the amount of trimming needed to be done to the front bumper cover to allow it to fit. We see this as a small price to pay for proper intercooler performance and placement. The last thing and perhaps one of the things that sold us on the superiority of this kit over other offerings was the hood scoop block off included from Crawford. Many people that we see with a FMIC kit on these cars are quick to leave the hood scoop or perhaps install an oil cooler at the top of the engine bay underneath the scoop. Quite simply we feel this is a far less than ideal setup for both aerodynamics and cooling. From an aero perspective you are introducing lift at a critical point in the airflow and from a cooling perspective you are creating a high pressure zone behind the radiator. What is happening is that the air that flows through the scoop does wind up in the engine bay and as a result of that the airflow coming through the front of the car and flowing through our new FMIC and Radiator has a harder time flowing through the front end as the hood scoop forces air behind the radiator.

When you block off the scoop the lack of that airflow helps air coming through the FMIC and radiator. Yes, we are saying that with the hood scoop blocked off the car will run cooler and with a car like the STI this is hugely important! We also were able to re-use our COBB intake and air box within this install. Not all FMIC kits work with all intakes and in the case of the Crawford we know that both the COBB and OEM intake boxes work without issue. Another benefit of blocking off the hood scoop is that it allows you to remove the scoop diverter panel mounted to the underside of the hood, reducing weight at a point that is high in the engine bay is always a good thing. We also did our best to consider any weight being added by the FMIC in comparison to the OEM TMIC. I can tell you that the FMIC core is within 4 lbs of the OEM support bar and the brackets and OEM TMIC removal make up that difference. The piping is all aluminum and with the amount of weight removed with the systems we deleted we are very close to being even in terms of weight gained or lost with all of the weight being placed in a more ideal location than it previously was. With the install of the FMIC buttoned up we had a few details to finish before moving to the fuel pump install.


Crawford FMIC front mount intercooler piping GR STi installedHere you can see how ideal the pipe routing is overall. The KEY is that the hotside piping STAYS on the hot side! Most other kits have the cold side piping routing back over the hot side of the turbo and frankly this baffles us. 

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