How To Turbo Your Non-Turbo Subaru – ej22 Specific

How To Turbo Your Non-Turbo Subaru – ej22 Specific

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.

Updates :
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

  • Turbo
  • Exhaust
  • Intercooler
  • Blow Off Valve
  • Intake
  • Oil Lines
  • Coolant Lines

Turbo

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.

td04 subaru wrx turbo

Exhaust

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.single port headers for subaru2)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.

Brewed Motorsports Turbo Subaru Up pipe

turbo up pipe in gc8 subaru

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.

exhaust on a turbo rwd subaru wagon

Intercooler

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.

2) 02-04
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.

2002 subaru wrx intercooler

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.
Your call.

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.

turbosmart veeport blow off valve on subaru impreza wagon

Intake

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.

custom intake on turbo subaru wagon

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.

turbo ej22 engine bay of a subaru impreza

Oil Lines

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.

old feed line on turbo subaru impreza wagon

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.

oil return line from turbo to engine on subaru impreza

Coolant Lines

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.

Coolant Feed

When facing the engine– this is the left side, under the back of the intake manifold.

coolant hookup on turbo ej22
coolant line on turbo ej22 subaru

Coolant Return

To the right of the throttle-body, behind the intake manifold.

coolant hose in subaru engine bay
coolant return line on turbo ej22 subaru

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.

Clutch

* 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.

Clutch Master FX250 clutch on Subaru engine

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.

subaru impreza wagon with turbo kit

Hey girl.

canards and fender flares on subaru impreza wagon

38 thoughts on “How To Turbo Your Non-Turbo Subaru – ej22 Specific

  1. Hey. I enjoyed reading through this write up, very informative. I have a ej22e in my car currently and I have some ej25d heads in the garage.. Do you think it would run okay if I did the low boost setup with the 25d heads on the 22e block? I like the torque of the 22e but I know the 25d heads flow quite a bit better.. Even trade off?
    Thanks

    1. I am not 100% sure if it would be an even trade off or not– you would have to do a little research and see how that setup your change your compression (those heads on your block). If it changes it enough, a tune would be highly recommended to make sure your engine is in the correct parameters.

    2. It will work well. It will actually lower the compression ratio a bit and keep the nasty detonation monster away. plus it nets a very nice top end. as always, invest in a good wideband af sensor (not a prosport please) and keep an eye on the air fuel ratio.

  2. I had a few questions about your turbo setup on your na ej22. I read that you wedged your intercooler between your firewall and the hose supplying the intake manifold. I was wondering what kind of issues you are running into with the hose having such a high amount of force being applied to it? Did you run a 4 ply silicone hose? Did you just use the oem wrx hose? I also noticed that you teed off the oil PRESSURE switch below the alternator. From all my experience that switch is pressure related. I was wondering if there is another one on the car or if a 2001 obs ecu does not reference oil pressure in there parameters? I am also a little interested in the boost control side of your setup I noticed that you are running a high boost of 8 psi. I was wondering how you are controling the boost on your car? I noticed you are running the stock td04 turbo of the wrx I was wondering what kind of afr’s you are seeing at 8 psi and at idle? I also wanted to say nice looking car! Have a great day!

    1. I used one of the Spectre ones from the auto parts store– the OEM one should work as well. I haven’t ran into any issues yet. I believe I had to trim it down a little, but that was pretty easy to do.
      I know on a ’99 ECU, they can run fine without that sensor– but there is no reason not to run it since t-fittings are available. I believe there is one other pressure sensor on the engine. Almost all builds like mine run the exact oil feed setup that I do– and they are various years of the ej22.
      I am running no boost controller or any form of engine management. The OEM wastegate on the turbo is what is regulating my boost.
      Not sure on the AFRs. I don’t have a wideband air to fuel installed. I will eventually after I decide to tune it finally.
      Like I said, the car has been running like this for over 5 years now. I researched for over a year before I finally turbo’d my car and there were enough people already running a setup like this with no issues that convinced me to do it. Tuning would definitely produce more power.

      1. I’m in the middle of turboing my 09 2.5i. I took a spare oil pressure plug like is on the front galley, took the sensor out, drilled the hole out bigger, and tapped it for the stock avcs banjo bolt from a STi.

        There seem to be more fitment issues with the intercooler the way I’m going about it, but it’s also a different

        1. That works too. I didn’t want to drill my block when I already had an adapter. But, not a bad idea on your part!
          I swapped to a 06/07 WRX intercooler and I have plenty of room to play now.

  3. Great read. Read through it and think you forgot a few minor-ish details. Colder plugs, O2 relocation specifics, vacuum routing (I find this is some of the least documented among all write ups), wastegate settings (I know certain years have different psi ratings, but it would be useful to emphasize the importance of ensuring that it works properly, and if not to get a new actuator assembly with a spring to control the opening or the wastegate), and fuel type/fuel pump used. Overall great documentation! Also how have your oil temps differed from before turbo to now? And what oils do you use when you drift? Any knock experienced? Coolant stays at a good temp? Did you upgrade fuel lines for increased pressure? Also, I would recommend (for readers) to compression and block test the engine before turbo as increased pressures will undoubtedly blow a ring or head gasket if they are on their way…

    1. Appreciate it.
      I don’t actually run colder plugs. I have in the past, but I’m running OEM plugs now with no difference.
      Up-pipe should already have a bung in it for the O2 sensor.
      Good call on the Vacuum documentation. It’s super simple, but I do remember tapping my boost gauge in incorrectly right away and that sacrificed me some PSI. Both td04 turbos that I’ve run hold constant at 8psi. One was from an 02/03, current is from a 04/05.

      My stock fuel pump handled everything fine– then it died around 160,000 miles or so. Which is not surprising. I attribute that the miles, not too much work. I put in a 2004 WRX fuel pump in since I already had one laying around from a donor car.
      Fuel type is always 91 octane minimum– it’s always good to combat detonation with quality octane.

      I don’t have an oil temp gauge in my car anymore; but when I did I hadn’t noticed any significant tempt changes.
      In the summer I run 15W40 Diesel oil in the engine. It provides great lubrication, especially in the heat.

      Nope, no fuel line upgrades. The things that I documented in this article is literally everything that I had to do to initially get the car up and running. Crazy simple– most people don’t believe me how easy it is.

      Another good call– compression test is a good call.
      I didn’t do it before I originally boosted. But, 5 years later I did before I converted it to RWD and compression was still perfect.

  4. I so want to do this to my 97 OBS!! I just installed a new Weapon-R Secret Weapon intake. Im wondering if this will somehow work with this type of turbo setup? Also I have Delta torque cams w/ported heads, what is your opinion on that? And it was a little unclear, will the stock headers work? I have EL headers from subie4x4 on EBay. These are bolt-on replacement for the stock headers. Oh man Im excited to try this!!

    1. You can probably use the Weapon R intake and hack it up to make it work– but I wouldn’t expect it to work without modifications.

      With Delta Cams & Ported heads, I would strongly suggest tuning the car right when you turbo it. I am not sure if the stock ECU will be able to handle all of that together.

      Stock headers will work, you just need to get a custom up-pipe made.

  5. Hi. Your article is very helpful. I have a 93 legacy that previous owners converted by putting turbo heads on the NA engine. I bought it while it was running pretty well, but had a few issues including an exhaust leak that turned out to be from the passenger side dual port exhaust head gasket. Went ahead and fixed that – big mistake! Life was good for about 10 miles and then boom! At first I thought it was the turbo, but after swapping that and still gushing oil I checked compression and cylinder 4 was gone. Ringlands failed I presume. Apparently added backpressure was the breaking point. Anyway, I bought what I hope is a working NA engine to swap in. My pre-existing inlet and exhaust will do fine, but without the turbo heads I need to set up the oil and coolant lines the way you lay out. A few questions on that:
    – Any repercussions running the oil outflow to the passenger side breather? How does that side breathe? Would a T-fitting work for that or would that just encourage oil to go inappropriate places?
    – A commenter above asked if you could really lose the oil signal (pressure I take it) from the fitting under the alternator without repercussions. Would that likely be the case with my earlier ECU?
    – The fittings you use for coolant are also what feed the throttle body and idle air controller. Is there enough flow for me to T-connect the output and return lines to serve both the turbo and those things in parallel?

    1. Sounds like a rough situation..

      •I have seen no negative effect from running the oil return into the head at that location.
      It really doesn’t breathe anymore, to be honest. The best thing to do would be to tap in a spout towards the bottom of the valve cover and return the oil there. I’ll probably get around to doing that one of these years.
      •I use a t-fitting under the alternator so it feeds the oil and still utilizes the OEM sensor.
      •I didn’t t-connect anything in my coolant line. The coolant feed to my turbo & the coolant return locations were once connected with a hose. Now there is just a turbo between them.

    1. No reason that it shouldn’t.
      If your engine has dual port heads it will be even easier since you can use a WRX manifold and Up-pipe.
      You’d just need to notch and reinforce the crossmember or swap out for a WRX one.

    1. If you are taking it all apart already– ARP head studs are never a bad idea. However, I am running OEM bolts.
      I have never had an issue with my headgaskets, so I can’t give you a solid opinion on using the ej22t ones.
      The one thing to look into would be to see if there is a difference in thickness of the gasket. If there is a difference then the compression will change.

      1. Got yea, what about the Wrx cradle how does that work in there? (Control arms, sway bars) any concoction of different years?

        1. If you could snag the entire front crossmember with the tie-rods, control arms and everything– that would be optimal.
          The WRX setup would give you a slightly wider track, which usually translates into better handling.
          2002-2007 setup should work.
          Rear sway bars are direct fit – I am running one from a 2003 WRX.
          I’m not too sure if the front sway bars are direct fit or not– I’ve never looked into that.

          1. wrx wagon won’t widen the track.

            also you can reuse your front control arms. if you are pre 1999, you can shim the front bushing 6mm (1/4″) with a spacer or washers. no big deal.

  6. This has been an awesome and very informative write up! I am piecing together a build based on this but I just has a question about the size of the oil feed line, oil feed T fitting, and oil feed adapter for the turbo? Thank you once again!

    1. Hey Jason, I’m glad to hear it’s been of help!
      If I remember correctly, the bolt / fitting needs to be a M10x125 on one end with a 150 on the other end.
      The best way to go about this though.. would be to take out the sensor from under your alternator and find the OEM banjo bolt from the turbo and take those in to get them measured. I did mine so long ago that I could be slightly skewed.
      For the line, I went to a store that specializes in hydraulic hoses and explained to them what I need and they cut me their recommended diameter to fit my fittings

  7. I assume you leave it running after you drive it for turbo cool down time, cuz most scooby turbo put the coolant reseviour above the turbo for thermal siphoning also did you leave the coolant line going through your throttle body into the idle air?

    1. I do not. I just shut her down and walk away… looking back a few times, of course.
      I understand where you’re coming from though.

      Yes, I left the coolant line hooked up.

      1. Ok so you went coolant to turbo then iac to throttle body to return also what kind of vacuum set up do you got going on? Curious as to how to get the wastage situated

  8. Hey Ross, another question on your set-up. Sounds like you have a custom made up-pipe? Are you single or dual port? Did you have to clock your turbo? I was told if I got a subachad up-pipe I have to clock the turbo. Also with that set-up I cant run a stock down pipe? Basically if the turbo is in the “stock” location your saying an 02-07 WRX downpipe will work as long as I have the correct crossmember. Thanks

  9. I’m sure its listed somewhere in the comment section, but will the stock compression ratio do okay with the boost? The highest octane in my area is 91…. having 9.5:1 is kinda iffy in my eyes.

    1. Use a wideband and 25D injectors and keep an eye on afr’s. 10.5:1 should be safe on 91.

      Other option is to install ej25d dohc heads. drops compression ratio to 8.9:1, while increasing top end flow considerably.

  10. This was really helpful! Considering doing something similar to my euro 98 forester (ej20j engine), pretty much same engine as the ej22 I think. I still want the car to be reliable, how can you know that the ecu are able to compensate for the extra air? Or is the stock ecu running so stupidly rich, that adding more air, still keeps the engine within reasonable air-fuel ratios?
    Sorry for my english.
    Many thanks.

  11. I also recommend using the EJ25D injectors as they are slightly bigger than the 22E injectors. The ecu will not freak out on this and will simply adjust the trims. You might need these extra cc’s of fueling on a good hot day.

    This is coming from personal experience. Me and my roommate turbo’d his ej22e legacy postal wagon 2 years ago. only problem we’ve had, was our old worn out vf11 crapped an oil seal

    We also had a bad experience with the oil line return being in the breather. It just simply would not flow fast enough on our dual port phase 1 ej22e. It smoked like a mosquito fogger. In the end, we tapped the rear of the valve cover for the return instead. Hope my insight helps.

  12. Also, with anything before 99, the lower control arm will require 6mm(1/4″) of spacers or washers in the crossmember mount of a wrx crossmember. it’s not a big deal, just, early front bushings were 55mm wide, later ones were 61mm wide

  13. Hey, I used this post a lot to help me for when I did my na-T build! It was a huge help! I also did a full write up on the process for a dual port EJ22E. My blog is Turbotimer.org. Here is the link below to my write up.
    http://turbotimer.org/2016/01/so-you-want-to-turbo-an-ej22e/
    I also just recently did a EJ22T swap into the same car and here is the link to that write up.
    http://turbotimer.org/2016/03/ej22t/
    I’d love to help people feel more comfortable doing this turbo build and feel posts like ours are the best ways to show people it shouldn’t be a scary endeavor.

  14. Hey Ross, I was wondering if you could take a picture of that up pipe installed, more specifically I want to see the o2 sensor plugged in.

  15. I live in cali and have been want to do this for a long time but im worried about smogging my car will it pass smog by chance if not are there any possibilities of being able to get it to pass

  16. Boosted my ej251 in the same way but I used the crossmember , and wrx take offs and a front mount . Never blew up . Ran it that way for months and sold the engine to another guy who is still running the engine to this day . No tune . I did adjust my fuel pressure . As fast if not faster off the line than my wrx . Almost not turbo lag .

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