Engine Selection: The JDM Question
I frequently get asked about imported Japanese engines (or Japanese domestic market, JDM). They seem to be cheap, plentiful, and are swapped into WRX’s “all the time.” Before you jump one though be sure to research a little, as it’s not as simple as it sounds.
To source, one must find a JDM importer that carries Subaru motors, such as jdmenginescorp.com. Care must be taken to be sure that it is a reputable business; many have been burned by return fees on broken/incorrect engines. The issue with JDM, is it can end up as a “luck of the draw,” choice. Most of the engines are in unknown condition with low mileage anywhere from 30-60k (due to strict Japanese emissions laws). Good importers will check compression and have a warranty on parts, but usually won’t pay for return shipping or labor when, for example, you get an engine with bad rod nock. The ECU can be an issue as well as it may or may not be sold with the engine and doesn’t have much support in the states (exception being the high end V7, V8, etc. STI engines). Furthermore Japan has much better gasoline then us, therefore requiring premium fuel at the very least (even in NA engines)
The plus side to the engines is they are markedly cheaper, and almost always low mileage. So if you are good with mega squirt or figuring out wiring this may be an excellent option. Out of the JDM engines turbo engines there are a few I would\not recommend.
Also arguably the best 4cyl turbo’s made are jdm. The Version 7 and Version 8 STI Engines are, for all intensive purposes, as close as you can get to factory built rally engines from Subaru. These engines come with a high premium, usually priced at 5-7k, but are the end all be all for the Subaru 4’s. The other plus side of these high performance imports is the fact that there is a bit more support for tuning/wiring stateside.
- The jdm ej20tt is a twin turbo found on the b4 legacy with 240 hp, it sounds cool but the twin turbo set up can be a massive headache to deal with. Guys who get it usually ditch one of the turbo’s for a simpler, more reliable system.
- The EJ20G, 20K, or 20H are all basically jdm wrx (legacy or impreza) engines, with each one going to a different set of years and having slightly different turbo/hp set up. The HP ranges from 230-300. The 20g is the most basic, 20h and K are different STI versions (version 1-8). The part compatibility with US parts may be an issue and more in depth research, specific to the engine you choose will be necessary for one of these swaps; you can’t just drop it off at a Subaru dealer and ask them to change something, you have to figure it out and tell them which part exactly or just change it yourself. But then again for our 914 it’s a great way for an industrious guy to save some cash and still have great engine.
I would suggest forgoing the savings/headache of the JDM and stay with US gear. You have many options and some just as inexpensive as the JDM stuff but with less headache. Furthermore parts and service will be a lot easier all the way around sticking with USDM.
220-300HP/tq Engine selection
Engine Options: Engines Less than 300HP
In this post I discuss engine options in the less than 300hp range. Of course this is all my humble opinion and should be taken as more of a guideline to get you started in researching which engine is right for you. Check the links section of the conversion info page for some good sites to continue your research at.
-NA 6 Option-
There are four feasible engines that can work in this category. I will try to shed a little light on each and rank them, from least to most recommend for use in the 914 swap. I should add that I’m less familiar with the upgradability of the 6’s than the 4’s. But in general it is much easier and cheaper to extract more power out of a turbo set up than an NA. So bear in mind that if you choose to go 6, its more of a dead end for upgrades (without a high relative cost), but then again they all have good power levels so you may not ever want more.
- EZ30R, Found in the 2004–2009 Legacy 3.0R, Outback 3.0R and 2006–2008 Tribeca. This is basically a factory revamped version of the EZ30D. It has 240 chp stock and a wider upgrade path, generally turbo options, (shops have taken it to 1100 hp). Also has VVL and AVCS (subaru’s variable valve timing) that helps to give a nice wide torque curve and 3 port exhaust heads. However this motor has a drawback, CANBUS Electronics. Basically what CANBUS electronics do is make the cars wiring a bit more simple and efficient for the OEM vehicle. The problem is it eliminates the option of a stock ecu swap, as it would require someone to take every piece of important electronic equipment and swap it into the new vehicle. The workaround is simple but expensive, an aftermarket ECU such at $1.5-3k will be necessary.
This option is my least recommended, this great engine comes at the expense of one of the biggest strengths of the Subaru conversion and that is the relatively low cost to convert. The engine can be found for $1500-$2500 (plus $2-3k for ECU) used and provides great all around power mid and low rang hp/tq, basically the cost of the engine alone would be close to the cost of the complete drivetrain conversion with a different engine choice (like the eg33 for example).
- EZ36R, Found in the legacy 2010+, outback 2010+, and tribeca 2008+. This is the next step of the EZ engine series and basically a maxed out EZ30R. With 260 chp, and the same VVL and AVCS systems as the 30R, the engine is as good as it gets in regards to stock 6cly power. The drawback however is a big one; similar to the 30R it has CANBUS electronics. Also it’s got some insane geometry inside with asymmetrical connecting rods that make upgrades pretty much nonexistent. The big plus with this motor is the ability to run cheap 87 octane fuel and still get high HP numbers.
I would rank this engine tied with, or slightly ahead of, the EZ30R for the 914. The cost 2000-3000$ (+ $2-3k for ECU) is high but if you are going to spend the money to get the ECU why not get the one with higher HP and 87 fuel.
- EG33, found in the Subaru SVX 1991-1997. This engine was Subaru’s second foray into the 6cly world, and a very interesting choice. It comes with 230 hp. Not nearly as technically advanced as the EZ series, and a bit larger but this motor does have several distinct advantages for the 914. First it has been around for a long time and is based on an ej22 block, the upgrade paths are more prevalent. Secondly, you will not have to deal with drive by wire and immobilized ecu issues. Thirdly because it is based off of the ej22 (its basically an ej22 with two extra cylinders and extended ej25d heads) it inherits its near bombproof reputation. Finally, and most importantly this motor can be had for 500-1500 (though almost always north of 100k miles, as it’s up to 30 years old).
This is my second choice for the 914. It is a good, sturdy engine and ridiculously cheap for the power it provides but is pretty large and probably will necessitate cutting of the rear trunk.
- EZ30D, found in 2000-2003 outback and legacy’s. At roughly 212 chp from the factory, it seems to have the lowest hp number of the bunch. You can tell the difference between the others by the aluminum intake and its single exhaust port heads (looks like a long slot or oval) as compared the later 6’s or the metal timing cover/size when compared to the eg33. It has two plus sides when compared to the latter EZ’s, cheap drive by cable, non CANBUS and you can pick this up for around $1-2k. Furthermore the 212hp mark is deceiving, both the intake and exhaust is extremely constricting on the donor car and from the swaps that have been done/dyno’d (in the Subaru world) just upgrading to something less restrictive will put power up to 230-240hp.
I would rank this motor highest in comparison to the other options in this category. Due to its more modern design and timing chain (that does not need to be service for the life of the engine) it is smaller/lighter and more reliable than the eg33. furthermore the ECU on the EZ30D substantially less expensive than the EZ30R and EZ36R. However to clarify it does not have the VVT or AVCS of the later EZ’s.
-Turbo 4 option-
For the 4cyl options you are looking at a plethora of EJ series turbo engines. The great thing about these engines is the massive amount of aftermarket support out there. That upgradability brings the ability to easily work your way up the HP scale (up north of 300hp) or fine tune what you already have.
- Ej205, 227 Hp sold on the 02-05 Impreza wrx. Through all its years the wrx has a massive aftermarket following, you can get pretty much any upgrade part imaginable. They are all drive by cable and do not have a chipped key this is going to be the most versatile conversion motor with examples of power ranging from 227-350+ reliable chp. The price will be 1500-3000 for a complete used engine.
1.5) It should be noted that this is a great builders engine, as you can find separate heads and blocks etc for sale all over forums (nasioc, RS25). One of the great options is to get 914 running with a cheap ej22e NA Subaru engine and slowly build up your own ej205 engine as you drive, and when its ready to go, just drop it in boom almost zero down time for your 914.
- EJ22t, 160HP found on the 91-94 legacy SS. This is another great option, with stock fixings it is quite low on HP, however if you add an intercooler, upgrade to a wrx exhaust, injectors, and td04 turbo, and a simple piggy back ecu it will push +240chp. It takes a little work but you can be into a 240hp reliable engine for under $1500 easily. Furthermore it has a bit better torque curve than the EJ205. Unfortunately these engines are hard to come by and more sought after for their closed deck block.
- EJ255, 230 hp found in the 05-07 wrx and legacy GT. Basically the same deal as the ej205, drawbacks include drive by wire and a chipped key. But for that and a little extra money you get around 20 more ft/lbs of torque, a better curve, and more potential power. 2000-3000$
Really for a low budget build my recommended engine choices are either EG33 for NA power or EJ22t in the turbo realm. When looking at the total cost, they will be close to the same with the EG33 winning out by a couple hundred (no turbo, exhaust, intercooler, aftermarket ECU to deal with) however the potential power of the ej22 is massive as it is one of the best blocks Subaru ever made (stronger closed deck block, with oil squirters, capable of 350HP with stock internals).
For the more moderate budget the ej205 would be my suggestion, with its massive following you can really fine tune the power to match your driving style and the 914. Or the EZ30D as it you still get the NA 6, like the eg33 but an all-around better engine.
Finally for the balls to the wall kind of builds the EZ36R or a V7/V8 STI engine will get you some pretty fun results.
Hopefully you have found this information useful, for more, be sure to check out the rest of the conversion info page. Feel free to email me any comments or questions you have.
Sub 200HP/tq Engine Selection
In this post I discuss engine options in the 130-200HP/tq range. As usual this is all my humble opinion and should be taken as more of a guideline to get you started in researching which engine is right for you. Check the links section of the conversion info page for some good sites where you can continue your research.
-2.5 Liter-
- A. EJ251: If you would like to go the easy route I would suggest going with a phase 2 ej25 or the EJ251. These run from 99-2004 in all of Subaru’s models and make anywhere from 165-185HP. These are great engines; sohc make for inexpensive cam upgrades and easy timing belt replacement, there is no immobilizer or drive by wire electronics to deal with. Furthermore, you can avoid too much trunk cutting with the phase 2 engines as you can flip the intake without relocating the AC or alternator; you just need a spacer (preferably phenolic). One issue that does come up however, commonly high mileage engines develop head gasket issues.
- B. EJ253: The 2005-2009ish, basically the same engine as the ej251, but with more electronics. Earlier years have less, latter have more; ranging from drive by wire, immobilizer key, to CANBUS. Of which, all of these need to be overcome for use in a 914; a slight hassle, but not insurmountable. However these engines are much less likely to be prone to HG failure of the earlier series.
- C. EJ25D: The EJ25D is an early DOHC version of the NA 2.5L. It has a lower HP rating, has smaller main bearings and a slightly more difficult timing belt service. Also the intake cannot be flipped without the loss of the AC compressor (without an extra thick spacer). However this is does have one advantage; if you are into engine projects (see 2.5/2.2 below).
-2.2 Liter-
- A. P1 EJ22E: The phase 1 EJ22 is arguably the most reliable engine Subaru has made in the past 20+ years. Used in the Impreza and Legacy from 90-98 The sheer number that can be found still driving around at 200-300k+ miles is a testament to how long this little engine will chug. However with only 135hp it seems reliability comes at the cost of power. Another plus is the cost of the engine, an ej22e can be found for 500 in good shape pretty regularly. There is a difference in early/late head design, with different valve trains and dual vs single exhaust ports. It does have one interesting advantage/option as explained below (2.2/2.5).
- B. P2 EJ22: any EJ22 found after 99 will be a phase 2 engine. It has redesigned head which is basically identical to the ej251 but with a single exhaust port. The phase 2 ej22 can be summed up basically as a more reliable (if possible) slightly more powerful version of the phase 1. It is phase two so the intake should be able to be flipped without losing the AC compressor as well. The one drawback is it is slightly more expensive and harder to find.
– Mix & Match –
- A. 2.2/2.5 aka HCF: A Phase 1 (phase 2 will work as well) ej22 can be found for next to nothing and if modified properly can become an torque monster, called a HCF or high compression Franken motor, this takes a little more work but can be a hoot of an NA motor. It requires you to find a 2.5L short block (phase 1 or 2 will make a difference in compression) and swap it out in place of the 2.2L and buy/install some cams. It’s all easy enough for a garage builder to do and results with some pretty impressive low rpm torque numbers that rally/autocross guys seem to love. The drawbacks are you cannot flip the intake without losing the AC pump and requires higher octane fuel.
Recommendations:
I usually steer people toward the EJ251, It has a good power level for the 914, simple to convert, and not too expensive to pick up used. The head gaskets can be an issue, but are not difficult to swap out when the engine is getting prepped for a swap.
If you have a small budget then the ej22 is the choice for you. Cheap and bombproof, at the cost of power but it’ll still be a respectable jump up from a type 4. Another advantage is the fact that you can get the conversion completed and sorted cheaply, then easily drop in another more powerful engine such as a turbo 4cyl or 6cyl, as a near plug and play upgrade at a later date.