Looking at the EJ motor can be intimidating so I wanted to start a thread about what can go in the trash to make the motor easier to work on, and what can be done clean it up quite a bit.
These are just a few of the things I will be doing personally, and is by no means complete and or necessary. I'll just touch on everything briefly and we can discuss any of them in other threads if necessary.
Emissions Equipment
The motor has several fuel emissions componants mounted to the engine. Connected to the turbo inlet/intake manifold/hose that runs to the back of the car is the Evap diaphragm and valving. Its job is to burn fumes that would otherwise escape from the fuel tank. It is used with a charcoal canister at the rear of the vehicle. since the 818 utilizes a different fuel tank and most likely a vented gas cap this entire system is unnecessary and can be removed.
EvapPurgeSolenoid2.jpgpcv0yp.gif
remove this, cap off the nipple on the turbo inlet and use a cap to close the tube on the intake manifold (also a easy place to hook up a boost gauge) You will have to turn off evap codes with your tuning software
TGVs! the tumbler valves on the car are bulky restrictive and heavy. People argue that they help with cold starts but really their main purpose is cold start emissions. Removing them saves a ton of weight, and the accompanying motors/wiring/vent tube really cleans up the top of the motor. Its also good for about 8-15hp depending on who you talk to. This is an easy and pretty much free mod anyone can do at home with a drill and a tap, a few bolts and some grinding equipment. It is well documented.
ditch this
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for this
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Air Pump
The 06 and up have an air pump that feeds air to the heads to improve emissions. the system is hideous and heavy at about 10lbs. The who assembly and wiring can be removed. You'll have to remove some codes with your tuning software and purchase some block-off plates $30-$80. But the difference is huge.
Engine Venting
There is a mess of hoses that accomplishes the venting of both heads, and the crankcase. These hoses travel around the engine bay in a series of rubber hose and hard pipes. The problem this presents is that it forces your engine to suck up and try and burn a ton of oil. leading to messy intercoolers, and lower octane ratings. the system also includes a pcv functionality sensor, which is typically bypassed (by closing the circuit in the harness and removing the sensor, and plugging the extra nipples). You can go a step farther and remove the wiring altogether from the harness. Don't remove the PCV itself, just the monitor, it limits the vacuum flow that the crankcase receives. Removing it altogether may cause problems. If doing this mod though its a great time to clean your PCV with solvent so make sure it moves freely.
pcv connection sensor.JPG
As far as what to do with the venting, a good quality catch can or air oil separator should be utilized to capture the oil from the intake system, and in the case of the aos, return it to the crankcase.
a few plastic elbows tees and careful hose routing can really clean up the venting system
not the cleanest aos install, but you can see what is happening here
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AC and PS removal
Removing ac and power steering will make a big difference in the front of the motor as to how much room you have, and you'll also be able to remove the wiring from both (not sure if all power steering pumps have a pressure switch. The factory bracket for the alternator and ac is massive, luckily you can use a alternator bracket for the 2.5RS with no factory AC which is a fraction of the size. Subaru P/N: 11711AA051, they are like $25 or less from the dealer . The item is shown in my post cool parts thread as well.
Throttle Body
See my blog post on this one, the factory throttle body has a coolant passage to keep the throttle and IAC from icing up.. many people just remove the hoses from both ends and connect them with a nipple. Pretty sure you can remove these hoses altogether but I will verify. You can go the extra mile and remove the nipples from the TB and even machine the passages all together if you want to really trim it down. Cooler air is always better so running it through a hot throttle body makes little sense.
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Fuel system
the fuel system on the wrx is pretty visually complex when you look at it, it's also run in series meaning certain cylinders run the risk of getting less fuel. Aftermarket fuel rails, while not a necessity until about 400 whp really clean up the look of the fuel system and let you ditch the spider under the manifold. They also eliminate having lean cylinders. Ditching the green brackets of death, designed to protect the injectors in a front end crash, make the injectors a lot easier to get to.
trash these before you lose your fingers
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replace this:
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with something like this:
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I may be missing a few but that's a start.