The age old question, ‘How do I turbo my Subaru?’
Normally, when you go about turboing a non-turbo car, things can get very expensive real fast.
That doesn’t have to be the case when it comes to boosting your Subaru– your ej22 (or even ej18) in particular.
I’ll say this right away– I took essentially the most basic, cost efficient route that you can take when you are looking to turbo your non-turbo Subaru. I turbo’d my car in April of 2010; over 5 years deep and still no regrets. I pulled the heads off of the block last March (2014) to check the internals before I converted my Subaru to rear wheel drive. With around 200k miles on the clock, the pistons looked great and there was still crosshatching on the cylinder walls. There may be better methods out there (such as actually tuning your car), but this has been working for me.
*Boost at your own risk…. and enjoyment.
June 15, 2015 – added 25% off Clutch Masters code to the clutch portion of this writeup.
June 16, 2015 – ordered a 2006 WRX intercooler since I kept having issues with the 2002-2005 intercooler coming loose.
Basic Subaru Turbo Kit Needs
- Blow Off Valve
- Oil Lines
- Coolant Lines
If you are looking to get a basic setup on a stock engine, then I highly recommend picking up a td04 off of a 2002-2005 WRX. The great thing about them is:
1) They are large enough to produce an ample amount of gain on your stock engine.
2) They are small enough that they won’t blow up your stock engine. (just be smart and keep it at 8psi or less)
3) With my setup, I hit full boost (8psi) at 2,450rpms. Virtually no turbo-lag whatsoever.
(Side note, how is whatsoever even considered to be one word? Neat.)
4) They are cheap. I picked mine up for around $125 in good condition. Even if they do have leaking seals or shaft play, they are easy to rebuild and kits can be had for well under $100.
This will be broken down into Header / Up-Pipe & Turbo Back.
There are two sides to this ej22 exhaust section– the dual port heads and the single port heads.
Header / Up-Pipe
1) Dual Port– consider yourself more fortunate. Being that your heads have two ports on them, you can run WRX headers, which means that you can run a WRX up-pipe. However, it’s not quite as easy as just bolting it up and calling it good. To make it fit your must either:
A) Notch your crossmember since your NA one doesn’t have the necessary dip to clear the up-pipe. It would be a good idea to weld in reinforcements after you cut out the metal.
B) Invest in a WRX crossmember. They will bolt right up to your N/A chassis and have the necessary clearance to run a WRX up-pipe. They can usually be had for affordable prices– around $100 or so. Just find someone parting out their wrecked WRX. Those part out threads are becoming more and more frequent as of recent.2)Single Port– this will require some custom fabrication, unless you happen to come across a used Subachad up-pipe or if someone for some reason decides to part out an AVO Turbo Kit. You have no choice but to fabricate an up-pipe that can curve around and clear your crossmember. Fortunately, I have friends with welding skills. I did check into an exhaust shop though out of curiosity and they quoted me $300-400. Somewhat expensive, but somewhat affordable at the same time.
For headers, really the only option currently is Borla. At the price tag they aren’t really worth it and they are still somewhat hard to find. I have MS3 unequal length headers on my car that were from a RS25.com group buy about 6 or 7 years ago. Your stock header will work perfectly fine– don’t worry, the turbo will give you that classic Subie rumble.
Turbo Back Exhaust
Once you have the up-pipe situation sorted out, the rest is easy. You can use a full turbo back exhaust from a 02-07 WRX. That can be OEM or aftermarket. I ran an OEM down pipe that was slightly modified (cut away some of the heat shield to make it fit) with a custom catback exhaust originally, but I have since upgraded to a full 3 inch turbo back exhaust made for a 02-07 WRX. Bolted right up. Only 1 exhaust hangar doesn’t match up if I remember correctly.
You essentially have 4 options here– 92-00 JDM WRX / STI, 02-04 WRX / STI OEM, the 06-07 WRX / STI OEM or a front mount intercooler setup. I assume that the 01-06 JDM intercoolers would work as well.
If you want to run the splitter, invest in a JDM one for the 92-00 WRX / STi or modify a USDM one. I run without one– no issues.
1) 92-00 JDM
These will provide an ample amount of cooling with minimal issues to none when it comes to fitting.
I am running one of these on my wagon, 2003 WRX to be more specific. The STi ones are slightly larger and may require you to shave down your throttle body some. The WRX one just barely fits into my engine bay. It is essentially wedged between my throttle body and firewall with no room to wiggle. It used to take forever to install it since there is no play and I had to get it back in the boot that goes around the throttle body.
3) 06-07 WRX / STI
I recommend this route the most. I may even invest in one of these. They fit in the engine bay very easily– as they aren’t quite as deep, but they are longer.
4) Front Mount Intercooler
These most certainly look the neatest– errr…. the meanest– but they aren’t necessarily the most effective with this standard turbo setup. While running a small turbo on relatively low boost pressure, you will experience a little more boost lag than normal. This may not be an issue for some since the looks and potentially more cooling can outweigh the downside of a little more lag.
Blow Off Valve
A blow off valve will be a necessity here. The OEM WRX bypass valve didn’t work on my setup. When trying to fit it on the ej22, the throttle cable interferes and hits it.
Do some research and find the sound that makes your ears happiest.
For my intake setup, it required a 90º elbow to clear the intake manifold. My original elbow was from an early 90’s JDM WRX. I believe you can also find them on the 1st generation Legacy SS turbos. That eventually tore and I went to good ‘ole Ace Hardware and found a heavy duty 90º elbow in the plumbing section for a handful of bucks. Sold.
From there, you just need the piping to either run to the MAF sensor or directly to the air filter if you have a MAP based engine. Weld some bungs in to attach some of the breather hoses, or go to your friendly knowledgeable automotive store and buy a universal intake pipe that has some bungs already.
Oil Feed– I went with a stainless steel braided oil feed line. I have it feeding from the engine under the alternator. There is a sensor down there that reads oil temperature. The engine has a few of these sensors– so technically you can just remove it, but what I did and recommend is investing in a T-fitting that will allow you to run both the sensor and the oil feed line.
You could technically buy an oil filter sandwich plate and feed it from there– but I have heard that those tend to leak after time.
You will need to find the right size and combination of fittings to get it to fit to the turbo.
Oil Return– I highly recommend going to a hydraulics store and using 5/8ths inch hydraulic hose. I used a hose from an auto store and it ended up being a heater hose– which the oil essentially began to disintegrate and it tore. Oil spewed all over my engine bay and it was no fun at all.
This attaches to the nozzle on the bottom side of the turbo and to a spot on the engine to recirculate it. I am just running the hose into the breather nozzle on the passenger side valve cover but I would recommend feeding it directly into the oil pan. You could either weld in a bung or install a WRX oil pan on your engine.
For the coolant lines, I’m going to let the photos mainly speak for themselves. It’s somewhat hard to explain where they tap into, but I did my best to highlight them.
When facing the engine– this is the left side, under the back of the intake manifold.
To the right of the throttle-body, behind the intake manifold.
Tuning & Management
Some people will swear to every single god out there that if you don’t tune your car, you will blow the engine almost instantly. Well, that’s not true. If you stay with a td04 on an ej22 and don’t push it past 8psi, you are going to have a good time. I have no ECU management, no fuel pressure regulator or anything else that you can name. My stock ECU is controlling everything just fine.
With that said, to get the most out of your setup– tuning would be a very good idea. There are a ton of options out there from a APEXI SAF-C, to the PP6 (Perfect Power 6) Piggyback on the budget side. Then you get into AEM and on from there.
Tuning is never a bad investment– but in the last 5 years my car has ran fine without it and performed strong.
For this route, I also highly recommend investing in a wideband air/fuel guage.
* To get 25% off of your entire order from Clutch Masters– enter the code : automersion at checkout.
My stock clutch was not feeling very well about itself when I was in 1st gear. From about a 5-10mph roll I could floor the car and it would be fine, but if I tried to launch it the clutch would slip horrendously and the wicked smell of a burning clutch would fill the cabin. I very highly suggest upgrading the clutch to be able to utilize the full potential of it.
I am running a Clutch Masters FX250 clutch currently and I can easily say that this is one of the best clutches that I have ever felt. The other one I love is the Clutch Masters FX400 8-Puck that we have in my brother’s RWD WRX. Even with my car being RWD and drifting / dropping the clutch, there is nothing but grab and hook-up.
Go Get ‘Em Tiger
That is essentially everything that you need to know about turboing your non-turbo Subaru. For you ej22 guys and gals out there, you really have the best naturally aspirated Subaru engine out there for this. I cannot stress enough how much enjoyment that this setup has brought me. A simple kit like this could be done for under $1,000 dollars if you can source it and install it yourself. Having friends (or yourself) that can weld will save you a lot of money.
If you need more convincing– check out this build thread by susiemk,
he is one of the OG guys that took on boosting the ej22:
EJ222 (Phase II MAP 2.2l) / ej251 Turbo Conversion Parts List (boosted since 02/2004)
Otherwise, there are more and more DIY ej22 / ej251 turbo’d Subarus coming to life all the time. For even more builds and a mass amount of information pertaining to every single nut and bolt on your car
–be sure to create an account on RS25.com!
The thousands upon thousands of members on there have collectively pointed me
in the right direction all these years. I am very grateful for this community.